# 911 RSR with Tesla Motor...



## kennybobby (Aug 10, 2012)

How much does a roller like that go for--what's the price range?


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## Jerhofer (Feb 10, 2018)

Subscribed


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## brian_ (Feb 7, 2017)

I assume that the "RSR" part is a reference to the body kit, and this is not an actual 1973-1974 race car. What year or series of 911 is this? One of the pre-1989 (before the 993 type) cars, with strut front suspension and semi-trailing arm rear suspension, both with torsion bars?

(Edit note: corrected "trailing arm" to "semi-trailing arm")


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## Jerhofer (Feb 10, 2018)

brian_ said:


> I assume that the "RSR" part is a reference to the body kit, and this is not an actual 1973-1974 race car. What year or series of 911 is this? One of the pre-1989 (before the 993 type) cars, with strut front suspension and trailing arm rear suspension, both with torsion bars?


I am MFOR1000's father and found the car on a local Craigslist ad. It is a '79 911SC so it does have the torsion bar suspension. It did come with the doors, the glass, the hood, the front fenders, seats, gas tank, bumpers, and assorted bits and pieces. He negotiated an excellent price for the car. As soon as I saw the ad, I sent him the link knowing that this was the type of car he was looking for. 

He ordered an RSR kit that will make the car look like the white car in the photo above. Those fenders will allow him to install some meaty tires for better traction. It should be a fun car when it is completed.


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## brian_ (Feb 7, 2017)

Jerhofer said:


> It is a '79 911SC so it does have the torsion bar suspension.


Thanks - that's the vintage I was guessing. The suspension may end up being important to how the EV components package in, but that vintage of 911 is very similar to a 944, so whatever was planned might work without much change.



Jerhofer said:


> It did come with the doors, the glass, the hood, the front fenders, seats, gas tank, bumpers, and assorted bits and pieces.


With any luck some of those (gas tank, and parts replaced by the RSR kit) can be sold to recover some of the cost. 



Jerhofer said:


> He ordered an RSR kit that will make the car look like the white car in the photo above. Those fenders will allow him to install some meaty tires for better traction. It should be a fun car when it is completed.


I think it will need relatively wide rear tires just for good balance, since the rear-mounted motor and mid-to-rear-mounted battery will leave this car tail-heavy.


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## Jerhofer (Feb 10, 2018)

brian_ said:


> I think it will need relatively wide rear tires just for good balance, since the rear-mounted motor and mid-to-rear-mounted battery will leave this car tail-heavy.


At this point, he thinks he can mount one set of batteries in the rear and the other set in the front with none in the middle. So the weight distribution may not be much different than a stock 911 which has nearly 60% of the weight on the rear. 

However, the total weight will probably be higher. The front torsion bars are easily adjusted for height. Adjusting the rear torsion bars is more difficult. There are adjustable trailing arms available which would make the rear adjustment easier.


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## brian_ (Feb 7, 2017)

Jerhofer said:


> At this point, he thinks he can mount one set of batteries in the rear and the other set in the front with none in the middle.


My understanding of the plan for the 944 (which has a tunnel for the drive shaft in its torque tube) was to basically duplicate the stock Volt configuration, with central tunnel and rear seat sections of the "T" pack. The 911 doesn't have much of a tunnel, so it makes sense to change to rear and front packs.



Jerhofer said:


> So the weight distribution may not be much different than a stock 911 which has nearly 60% of the weight on the rear.
> 
> However, the total weight will probably be higher. The front torsion bars are easily adjusted for height. Adjusting the rear torsion bars is more difficult. There are adjustable trailing arms available which would make the rear adjustment easier.


I agree that the total weight will probably go up (it always does in long-range EV conversions). With a front battery pack replacing the fuel tank, perhaps the net increase will occur mostly on the front axle, reducing the 911's significant rear weight bias (and minimizing the spring adjustment challenge).

Front pack placement should be interesting: 

the stock fuel tank location is entirely ahead of the front axle and below the trunk floor; it is awkwardly shaped (not a problem for the fuel tank which is just shaped to fill the space, even moulding around the spare tire), and 
the trunk (from the firewall to the front, including over the tank) has a very high floor due to the bizarre structure and brake master cylinder location of the 911 (and presumably a design to make a flat-floor trunk over the tank and spare).
Do you go too far forward in the awkward space, or too high in the trunk space... and perhaps gain a trunk in the rear?

Then there's this one...
A Tesla battery pack mutes this classic Porsche 911’s flat-six engine
... which fills the entire front trunk and tank/spare space. I can save you ten minutes of the video attached to that article - just jump to 2:28 for a view of the front pack (of Tesla Roadster modules), which is the only technical content of this typical two-guys-chatting promotional video.

The bigger rear tires are still desirable, even in a stock 911... although there are limits to that, as the usual "fix" for the oversteer which made 911's (and Chevrolet Corvairs) dangerous is a high roll stiffness bias to the front, which leads to lifting the inside front tire in hard turns, making the car into a three-wheeler (which needs sufficient front tire size to make this work).


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## Jerhofer (Feb 10, 2018)

brian_ said:


> The bigger rear tires are still desirable, even in a stock 911... although there are limits to that, as the usual "fix" for the oversteer which made 911's (and Chevrolet Corvairs) dangerous is a high roll stiffness bias to the front, which leads to lifting the inside front tire in hard turns, making the car into a three-wheeler (which needs sufficient front tire size to make this work).


Like this photo I took at the 1981 Porsche Parade autocross in Asheville, NC!


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## kennybobby (Aug 10, 2012)

i don't know if Joey is on our DIY site, but he has done an excellent EV conversion of a 911. Here he described how he increased the diameter of the front and rear torsion bars to carry the extra weight of batteries, etc. 

http://eporsche911.blogspot.com/2013/06/front-suspension.html

The front adjuster bolt is primarily used to preload the torsion bar during assembly and to make slight ride height adjustments to match left and right sides for alignment.


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## mfor1000 (Aug 22, 2017)

Very helpful info guys! 

I took a lot of weight out of it today. I removed the sunroof mechanism. I have a simple steel panel to bond back in it's place. That is supposed to buy me back about 30 lbs. 

I also removed all the sound deadening material in preparation for sand blasting. That was pretty heavy too, I should have weighed it. I'm going to try to do without, as I'm used to pretty loud cars and there will be no engine noise. I don't know how bad the road noise by itself will be. I can always add sound deadening later if I get annoyed. 

I also started doing recon on the rust situation. There was no rust under the sound deadening material on the pans...it looked like new under there. 

It has some rust at the rear attachments of the front fenders and at the rear bases of the doors. From what I've read, these are typical spots. This is where water and dirt get trapped. It also has some at the base of the windshield, especially on the left side.

I did a decent amount of cutting on the left fender attachment per the picture. I ordered another fender attachment panel since the lower part of it would be difficult to fabricate. I'm going to make my own patch panel for the inner part I cut out. Fortunately, the inside of the frame and the rocker were in excellent condition. 

The right side fender attachment may only be surface rust, I'm not going to cut it out. I'll see what it looks like after blasting.

The rear bases of both doors were pretty bad. I had to cut a lot out. I'm going to wait to do more until after I cut the quarter panels off for the new ones. I think I'm going to wait to blast till then, since with those quarters gone we'll really be able to clean it up in there. I also think I'm going to make a shield to prevent dirt from getting in there...it was packed tight between the panels. From these holes, I could see inside both rockers at the rear and I believe they're in great shape. 

I'll do what I have to to make this thing solid. I am considering putting a cage in it....there goes all my weight savings!


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## brian_ (Feb 7, 2017)

mfor1000 said:


> I also removed all the sound deadening material in preparation for sand blasting. That was pretty heavy too, I should have weighed it. I'm going to try to do without, as I'm used to pretty loud cars and there will be no engine noise. I don't know how bad the road noise by itself will be. I can always add sound deadening later if I get annoyed


I had a race-prepared Honda with most of the sound-deadening material removed. I think you'll be adding at least some of that back. 



mfor1000 said:


> I'll do what I have to to make this thing solid. I am considering putting a cage in it....there goes all my weight savings!


I hope you're able to leave the decision on the cage, or at least the details of the design, until you have a battery configuration worked out, so that everything works together.


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## brian_ (Feb 7, 2017)

kennybobby said:


> The front adjuster bolt is primarily used to preload the torsion bar during assembly and to make slight ride height adjustments to match left and right sides for alignment.


Very good point.  Torsion bar adjustments are like changing the threaded collar setting for the coil spring on a coil-over shock, or changing spacers between an axle beam and leaf springs. It does not change the stiffness of the spring (although it can change the effective stiffness a bit by changing the leverage), and if the suspension is carrying significantly more mass the spring (and shocks) should be stiffer.


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## brian_ (Feb 7, 2017)

kennybobby said:


> i don't know if Joey is on our DIY site, but he has done an excellent EV conversion of a 911.
> ...
> http://eporsche911.blogspot.com/2013/06/front-suspension.html


Interesting project - thanks for the link. 

Unlike most air-cooled VW and Porsche conversions that I've seen, this one uses the space on each side of the electric motor (in the stock engine location) for batteries (and even a few above the motor), and as a result - even though this project from a few years ago is using prismatic LiFePO4 cells - it does not need to use any rear seat or trunk space for battery.

Of course packaging with be different with the Tesla drive unit (instead of DC motor and stock transaxle), and with Volt batteries instead of the prismatics, but it's still an inspiration. Unfortunately, while it's almost possible to imagine a full Volt pack in the front (consuming all of the fuel tank and trunk space), I certainly don't see another one in the back with a motor there as well... so I assume that the back seat will be sacrificed.


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## Jonny Retrofit (Nov 6, 2015)

If you need AC, we make an electric kit for the 911 (and other cars). It is targeted at 12V ICE cars but can be adapted for most voltages.

Probably way down your priorities right now but more info here:

http://www.classicretrofit.com/electrocooler-complete-kit-for-911-1974--1989/


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## mfor1000 (Aug 22, 2017)

Wow, nice AC kit. I'll definitely consider that when the time comes. Frankly, I'll be glad when I'm worrying about stuff like that! I don't suppose you have a 380V heat version?

For heat, a friend suggested using aftermarket seat heaters. He thought those might be enough to get by for a while.

Today was spent reorganizing the garage for this project...the clutter was driving me crazy...

After that, I welded up a cradle for the Tesla motor to use on my transmission jack. Attached is a picture for anyone interested in doing the same. I tried to keep the CG in line with the shaft of the jack so it will be stable. I'll put the drive unit on it tomorrow and see if I need to add any more support.


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## mfor1000 (Aug 22, 2017)

I tried out the cradle for the Tesla drive unit. It worked great. Very stable. The chain ran over the front and it didn't move. 

I mocked up the position in the car and took some pictures. It fits in there pretty easily. The driver's side shock is close, but I think it will be fine. I'm just going to need to make a low profile mount for that side. 

I placed the bottom of the motor at floor level and where I think the axles will be at ride height. Nothing precise yet, just getting an idea what I'm in for. 

For the final mockup, I'll need the suspension with tires and wheels and no torsion bars so I can set the suspension to ride height. I may drill these shocks so they won't produce any force and allow me to use them more easily for mockup. 

It looks like I will be able to get all three modules from one Volt pack back there. The big one behind the motor angled up to the rear bumper. The second largest one on top of the motor, and the small one behind and on top of the big module. I may need to angle or lay down the small one to have enough room to clear the decklid. 

I hope to make a sealed box to enclose all the batteries. Then have airflow go through the grill on the decklid for the motor and battery coolers. I think I can make the bottom of this box double as a diffuser to clean up the aero under the rear of the car. I may even make a panel to go under the motor to the floor pan to clean things up more and protect the motor.

It looks like there is lots of room in front of the motor for the cooling pumps. 

I should also have room next to the small battery in the back up top for a contactor and electronics box that will be easy to get to.

I also found 'the guy' to do the blasting today. He does work for all the local Porsche shops. He has even blasted parts for the all aluminum Gmund coupe that was rebuilt locally....certainly he can handle a little 911 SC... He said he doesn't need a rotisserie. He can lift the car high enough with some padded forklift arms to blast the underside. I'm going to make some casters for it so I can take the suspension off. I don't think I have a lot of work to do under there.


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## Jerhofer (Feb 10, 2018)

Seeing the motor in place really shows how compact it is. The cradle worked well. Good job!


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## brian_ (Feb 7, 2017)

mfor1000 said:


> For the final mockup, I'll need the suspension with tires and wheels and no torsion bars so I can set the suspension to ride height. I may drill these shocks so they won't produce any force and allow me to use them more easily for mockup.


You might consider pieces of threaded rod (with a cheap rod end on the bottom) as shock replacements, to hold the suspension at any desired position. You could put some tubing around it to model the shock body for clearance. Just possible ideas...


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## brian_ (Feb 7, 2017)

mfor1000 said:


> It looks like I will be able to get all three modules from one Volt pack back there. The big one behind the motor angled up to the rear bumper. The second largest one on top of the motor, and the small one behind and on top of the big module.


I'm puzzled... the first generation Volt battery has 9 modules (7 large + 2 small), and the second generation Volt battery has 7 modules (3 large + 4 small). So what does "_all three modules from one Volt pack_" mean? By "pack" do you mean just one part of a Volt battery, either the part in the tunnel or the part across the back?

Also, you're talking about three sizes of module:

The big one
The second largest one
the small one
... but in any given generation of Volt, there are only two module sizes.

For reference, here's a description from GM of both generations of Volt battery:
Chevrolet Volt Battery System

________________________

*Edit:*
I think I have this figured out. You're probably using the Gen 1 Volt battery, which has

seven large modules of 12s3p = 36 cells (in 19 plastic frames per module), and
two small modules of 6s3p = 18 cells (in 10 plastic frames per module)
and

seeing three large modules plus one small module bolted together across the back and calling that the big module (42s3p = 126 cells)
seeing two large modules plus one small one bolted together at the front of the tunnel and calling that the second biggest module (30s3p = 90 cells)
seeing two large modules bolted together at the back of the tunnel and calling that the small module (24s3p = 72 cells)
... for a total of 96s3p = 288 cells (and 196 kg), a full first-gen Volt battery. I suppose the boundary of what to call a "module" is determined by electrical connections by GM (to get 9 modules), but it could be done by physical construction (to get 3 modules).


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## brian_ (Feb 7, 2017)

The stock rear engine location and semi-trailing arm rear suspension do look like they are working out to make an early 911 a good fit for the Tesla drive unit.


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## brian_ (Feb 7, 2017)

mfor1000 said:


> It looks like I will be able to get all three modules from one Volt pack back there. The big one behind the motor angled up to the rear bumper. The second largest one on top of the motor, and the small one behind and on top of the big module. I may need to angle or lay down the small one to have enough room to clear the decklid.


If I have understood your description of the Volt battery parts (in my post above), this means

a 90 cm (three foot) long portion across the car, behind the motor, 
a 60 cm (two foot) long portion across the car, above the motor and inverter, and
a 47 cm (18 inch) long portion across the car, behind the two-foot section and above the three-foot section
Have I got this right? Is there really that much height available, especially at the back? It will be great if an entire 16 kWh (nominal) Volt battery fits in the engine compartment of the 911.

Some cardboard or foam battery pack mockups might be nice to try out the fit.


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## mfor1000 (Aug 22, 2017)

I guess my use of the module terminology must be incorrect.  I am using two 1st generation Volt packs. Each pack consists of three physical blocks of cells (for lack of a better term). 

The largest is 33" long, the next largest is 25 1/2" long (including cooling 90 degree outlets, and the smallest is 20 1/2" (also including cooling 90 degree outlets). 

They are 11" tall and 9 3/8" wide at the base (10 3/8" with the mounting tray). They are 7" wide at the top.

Above the motor there is at least 16" of headroom to the package tray, so there is plenty of room for some mounts and the medium sized block of cells. The only thing that will be tight is the small pack at the back. I think I will have room to lay it on its side to clear the deck lid. 

I like the idea of the cardboard or foam prototypes. I think I'll do something like that. They will come in handy for the front packaging as well.

I want to keep them in the stock configuration if possible so I can easily use the BMS and wiring that came with them.


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## Kevin Sharpe (Jul 4, 2011)

mfor1000 said:


> I am using two 1st generation Volt packs.


How much do the packs weigh? What's the total capacity?


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## Ada Diamonds (Feb 9, 2018)

Is the RSR kit from GT Racing?

Do you need the back seat? If not, could you put one or both Volt batteries in a T configuration with a new tunnel between the front seats? That'd give you a lot better weight distribution than hanging ~400lbs that far back, no?

Love the build! 

JP


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## brian_ (Feb 7, 2017)

mfor1000 said:


> I guess my use of the module terminology must be incorrect. I am using two 1st generation Volt packs. Each pack consists of three physical blocks of cells (for lack of a better term).
> 
> The largest is 33" long, the next largest is 25 1/2" long (including cooling 90 degree outlets, and the smallest is 20 1/2" (also including cooling 90 degree outlets).
> 
> They are 11" tall and 9 3/8" wide at the base (10 3/8" with the mounting tray). They are 7" wide at the top.


Although I was confused at first, the way those groups are mechanically connected and externally wired makes them very sensible groups to work with. The "module" terminology is a bit arbitrary, so is anyone really wrong?

Thanks for the confirmation and more accurate dimensions. 



mfor1000 said:


> I like the idea of the cardboard or foam prototypes. I think I'll do something like that. They will come in handy for the front packaging as well.


The more I think about this, the more I like the idea of foam. You could build up the overall size (the 11" tall and 9 3/8" wide dimensions) by gluing blocks together, then hot-wire or wire-saw the shape into the sides, if you want a really realistic model. You could even cut the three large into the individual module lengths to try out other configurations, if necessary.



mfor1000 said:


> I want to keep them in the stock configuration if possible so I can easily use the BMS and wiring that came with them.


That makes sense... and it would avoid unbolting the stacks as well.


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## brian_ (Feb 7, 2017)

Kevin Sharpe said:


> How much do the packs weigh? What's the total capacity?


Some specs including total battery weight and capacity from GM (for the first generation):


> Discharge Power (10 s) 110 kW
> Charge Power (10 sec) 60 kW
> Usable Energy 10.2 – 11.2 kWh
> Total Energy 16.0 – 17.1 kWh
> ...


It would be interesting to see the weights of the three pieces, without the outer housing; they should be roughly 84 kg, 60 kg, and 48 kg, each less their share of the outer housing weight.


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## Kevin Sharpe (Jul 4, 2011)

brian_ said:


> Some specs including total battery weight and capacity from GM (for the first generation):


Many thanks... if that 196kg figure is correct then the older Nissan Leaf modules offer more than twice the capacity (24kWh) for almost the same weight (200kg)


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## brian_ (Feb 7, 2017)

Kevin Sharpe said:


> Many thanks... if that 196kg figure is correct then the older Nissan Leaf modules offer more than twice the capacity (24kWh) for almost the same weight (200kg)


I assume that the 24 kWh capacity of the Leaf is nominal, and so should be compared to 16 kWh ("total") for the Volt. So the Leaf has 50% more capacity, not twice as much.

A couple of factors to explain the difference between these battery designs:

the Volt battery is liquid-cooled
the Volt is a plug-in hybrid, so it has less space for battery capacity than a battery-only vehicle such as the Leaf; however, it must still perform in "EV mode" so it has a similar power requirement... which means high power density, at the expense of energy density

For anyone confused by the scale reading in that photo.... it shows only a half of Leaf battery. It looks like the stack of 24 modules across the rear, under the seat. There are another 24 modules under the floor ahead of that. Each module weighs about 3.8 kg, for a total of 182 kg, plus wiring, plus the housing.


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## brian_ (Feb 7, 2017)

The Leaf battery, due to its lack of liquid cooling and relatively independent small modules, does seem like an easier thing to package. On the other hand, the reason it gets away without cooling is that Nissan limits the demand on it to 80 kW (in the first two generations); in contrast, I think people putting Tesla drive units in high performance cars expect to use substantially higher power for at least a few seconds at a time. A first-gen Volt pack is rated by Chevrolet at 110 kW for 10 seconds, and that might be more conservative than some DIY builders.

This 911 is planned to have two Volt packs, for 220 kW (for long enough to blast up to highway speed) at Chevrolet's power rating.


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## Duncan (Dec 8, 2008)

Re Volt Batteries

They start off in the three Units you describe 
But if you look at them they can easily me taken into the different "Modules" - my pack has 7 off 2kwhr modules and 2 off 1kWhr modules

The advantage of taking them apart to module level is that you can then make "Bricks" the size you want

My car has two "Bricks" each with three 2kwhr and one 1kwhr modules - it makes sorting out the water flow easier as well

As far as weight is concerned I can pick up eack of my "Bricks" - just

If you are packing two Volt Batteries I think that you should do your planning at module level and design the "Bricks" that best suite your car rather than sticking to the Volt "Units"


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## Kevin Sharpe (Jul 4, 2011)

brian_ said:


> This 911 is planned to have two Volt packs, for 220 kW (for long enough to blast up to highway speed) at Chevrolet's power rating.


So, 392kg for ~34kWh 

Wouldn't Tesla modules be a better solution? Seven p85 Modules is ~37kWh @ 175kg, and a more useful twelve p85 Modules is ~63kWh @ 300kg. Obviously the 7 module solution would probably require modification to ~50V per module and I don't know if it would produce enough power for the application but half the battery weight is attractive


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## Nuts&Volts (Dec 20, 2011)

Kevin Sharpe said:


> So, 392kg for ~34kWh [emoji33]
> 
> Wouldn't Tesla modules be a better solution? Seven p85 Modules is ~37kWh @ 175kg, and a more useful twelve p85 Modules is ~63kWh @ 300kg. Obviously the 7 module solution would probably require modification to ~50V per module and I don't know if it would produce enough power for the application but half the battery weight is attractive



I’ve considered the Gen1 Volt pack route as well. You can get two Volt batteries for $2000 total if you shop around. That’s $0.06/Wh and capable of >400kW peaks. Seven Tesla modules would be $9-10000 or 5x more expensive and maybe 220kW peaks. Still amazing how cheap these batteries have become. I remember paying over $1500 for 4kWh of LiFePO4 6+ years ago. 

I’d love Tesla modules because the range would be awesome, but starting out it’s worth using the Volts cells to get the car on the road for less money. Then you can save up for the Tesla modules and use the Volt cells as a home battery backup!


Sent from my iPhone using Tapatalk


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## Kevin Sharpe (Jul 4, 2011)

Nuts&Volts said:


> Seven Tesla modules would be $9-10000 or 5x more expensive


I fully understand but just to be clear that's retail module pricing... you can typically buy a 85kWh pack in Europe for 14,000 USD which equates to 875 USD per module.

The way to get aggressive pricing is to work with others on a group buy strategy... it's halved our costs


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## Nuts&Volts (Dec 20, 2011)

Kevin Sharpe said:


> I fully understand but just to be clear that's retail module pricing... you can typically buy a 85kWh pack in Europe for 14,000 USD which equates to 875 USD per module.
> 
> 
> 
> The way to get aggressive pricing is to work with others on a group buy strategy... it's halved our costs




Oh wow that does help the cost argument quite a bit! Thanks for sharing 


Sent from my iPhone using Tapatalk


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## JP968 (Feb 11, 2018)

Kevin Sharpe said:


> So, 392kg for ~34kWh
> 
> Wouldn't Tesla modules be a better solution? Seven p85 Modules is ~37kWh @ 175kg, and a more useful twelve p85 Modules is ~63kWh @ 300kg. Obviously the 7 module solution would probably require modification to ~50V per module and I don't know if it would produce enough power for the application but half the battery weight is attractive


I'm working on a similar project (Porsche 964 purposely bought for conversion) but petrol guzzler still in it:-( 

Following Kevin's thought process and assuming magically we all join up to get the Tesla 18650 Module price down, is the p85 modules actually feasible for such a project? 
Based on my initial work i can get max 10 modules (plus the rear tesla S drive unit) in the 911 to be close to the original curb weight (u lighten the car by ~390kg taking out the petrol stuff).
Do we get with 10 modules enough power even in 50.4V config as per Kevin's suggestion (understand u get them here http://edisonmotors.net/shop/product/12s-converted-model-s-module-5-4-kwh-50-4-v-max-140?category=7) to have a 911 appropriate performance??

The Lotus Evora Bluelightning Project https://www.onpointdyno.com/bluelightning/ opted in the end as well for Volt batteries as they wanted to insure to have a C rating of >20 to get the optimum power for the Tesla drive... 

What do you think, 10 modules enough for a Porsche+ performance?

Ultimately, we all want to convert the petrol guzzlers because we know its the right thing to do but in the end it needs to become a better car and for a Porsche that means it needs to become faster...


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## mfor1000 (Aug 22, 2017)

Hi guys, my thought on batteries is to stay as low cost as possible for now. The technology is advancing rapidly and 5 years from now they will be much better and cheaper. For this reason I don't want to invest heavily in batteries. I'll just get it running with some inexpensive volt packs (they'll have enough range to get me to work and back). Then consider an upgrade in a couple years.

Sorry, not much EV progress...just doing regular car restoration stuff right now. I finished stripping the suspension and made some casters so I can roll it around and get it to the blasters and paint. 

I also decided to cut away the bottom part of the quarter panel to expose that area on both side. I want to make sure I get all the cancer. I cut some more out and think it is ready for the blaster to finish cleaning it up. It wasn't really any worse than I thought under there, but now I know for sure. It will also be much easier to patch now. I made careful cuts so I can weld back on the part of the quarter panel that I'll need later. Most of it needs to go anyway for the big fender flares.

I also made vin and build plate covers so I wouldn't need to remove them for blasting. I just tacked them on so they'll be easy to remove. Hopefully enough that they'll stay put. I'll consult the blaster and see if it is enough.


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## tylerwatts (Feb 9, 2012)

Love the casters. And the resto is coming along well. Good job so far.


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## mfor1000 (Aug 22, 2017)

The body is at the sand blaster. He's going to use soda for most of it and switch to glass beads when necessary. Then he's going to prime it with epoxy primer for the chassis and urethane primer for the body surfaces (more sandable). That will give me time to work on it without it flash rusting as it is humid here. I'll just have to sand the primer off in the areas I'm working on.

I've been disassembling the suspension components to get them ready for blasting and refinishing. I won't bore you with that...

I took a break from the suspension work and made some cardboard facsimiles of the batteries per a recommendation on this thread... I just used some old boxes and hot glue. They will be really handy to sort out the packaging...


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## Nuts&Volts (Dec 20, 2011)

I like the use of hot glue with the cardboard. Never thought to do that. Makes it easier to be accurate with them. 


Sent from my iPhone using Tapatalk


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## Duncan (Dec 8, 2008)

They look just like my batteries - only lighter! - well done


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## Ada Diamonds (Feb 9, 2018)

Especially if you're going to cage it, why not cut out the rear seats and put the batteries in front of the motor? The rear seat sheet metal is cheap, so you could easily put in new tin if you need to go back to stock later: https://www.restoration-design.com/store/product/PP222R

I think you could easily do a stock T of volt batteries in the rear seat area and between the front seats.

For the second Volt battery, could you put the top of the T on top of the rear seat area and the | of the T up where the fuel tank is today?

That way you maintain the rear bias of the 911 weight, but don't end up with a 30/70 weight distro with 1000lbs of motor and battery well behind the CG.

What body kit are you going with? GT Racing? 

Love love love the build!

Cheers,
Jason


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## Ada Diamonds (Feb 9, 2018)

Also, looking at 911_Tesla_Motor_Mockup_Bottom.jpg, it looks like you have some room to move the motor forward a few inches for better packaging and weight distribution.

You'd have some fore to aft angle in your halfshafts, but that's not a big deal as long as things are properly aligned.

Are you going to put in a Quaife LSD? http://store.evtv.me/proddetail.php?prod=QuaifeATB

Cheers,
Jason


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## mfor1000 (Aug 22, 2017)

Interesting thoughts on the rear seat area. I'll consider that. It would be really easy to cut it out right now and make lots of room. 

As for the T configuration, I'm going to see if there would be enough room for that. This car is pretty narrow and the seats aren't very far apart, but I might be able to squeak one in there. 

Just got it back from blasting...all pretty now. Time to start filling some holes. 

I couldn't resist throwing the cardboard mockup batteries in the front to see how they might fit. It does look like they'll fit, just have to turn one upside down. I'm not an electrical engineer, so if I turn it upside down, will all the electrons run out? 

Oh and as far as the diff is concerned, I'm likely going to start with the open diff and see what it is like. I'll have 14" wide wheels and tires on the back in a pretty sticky compound, so it may not be a big deal. If it bugs me, or if I ever have to break the thing open for a bearing change, then I'll likely put the LSD in it.


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## brian_ (Feb 7, 2017)

mfor1000 said:


> I couldn't resist throwing the cardboard mockup batteries in the front to see how they might fit. It does look like they'll fit, just have to turn one upside down. I'm not an electrical engineer, so if I turn it upside down, will all the electrons run out?



... but the wiring is all on the skinny side, which would then be on the bottom. Is that okay for access?

The Volt design with the coolant manifolds certainly does invite inverting sections when packing them together. Has anyone done this, and were there any issues?


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## brian_ (Feb 7, 2017)

mfor1000 said:


> I couldn't resist throwing the cardboard mockup batteries in the front to see how they might fit. It does look like they'll fit...


Slick. 
Are they all in space where there will be no conflict with vehicle systems when everything is put back in?

Also, can you make any required connections (such as for coolant) on the ends of the long (was "top" of the tee) set?


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## mfor1000 (Aug 22, 2017)

I think I'd be able to get to everything with the one being upside down. I'm going to be customizing that harness anyway. It would clear everything that has to go back in there including the hood. 

If I do put that battery upside down, I'll likely make a strut tower reinforcement frame and suspend it from that. I could hook it up to the harness and then drop it in with the frame and bolt in place. 

It also looks like I can put the Tesla DC-DC converter underneath it since it can't go all the way to the floor. That would help free up other space on top for the charger, heater, and vacuum pump.

The 12 volt battery will fit in the 'smuggler's hold' in behind of those packs. 

I also heard from the body kit people. They are asking for a shipping phone number, so that is a good sign! I can't wait to get those big fenders...


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## Ada Diamonds (Feb 9, 2018)

You'll have the only front weight biased 911 in history if you put all the batteries up front  How would you spring/suspend the car to get it to work and not understeer badly?

If you can't fit the T between the seats, could you put the two T-top batteries in the rear seat area and the two smaller parts of the T where the fuel tank was? Along with the motor rear of the axle, that should give you a really nice weight balance, no?

Cheers,
Jason


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## brian_ (Feb 7, 2017)

Ada Diamonds said:


> You'll have the only front weight biased 911 in history if you put all the batteries up front  How would you spring/suspend the car to get it to work and not understeer badly?


Hi Jason. It's worth going back to read the thread from the beginning - it's not very long.

That's just the front half of the battery; the same amount again is planned for the rear.


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## mfor1000 (Aug 22, 2017)

Yeah, that would be something, a 911 that understeers... 

I have two battery packs. One that will likely go up in the front as shown, but I will have another one in the back around the motor. I think there is enough space back there. So up front I have the weight of one pack, and in the back I have the weight of the motor plus the other pack. The body structure and suspension are also rear heavy, so I'll still have a significant rearward weight bias.

The unfortunate thing is that these packs will be very far apart, and cause a lot of inertia. So it will tone down the response of the car. That might be a good thing for it to be more calm with my driving!

I patched one of the holes this evening....many to go!


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## mfor1000 (Aug 22, 2017)

I haven't wanted to bore you with old car restoration stuff, but I'm making progress. I'm probably about half way through the metal work. My body kit should be here in 3 weeks. Just cutting stuff out, making replacement panels and welding them back in...I'll be glad to be done with this part!

Here are some exciting this old car fix pics!


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## mfor1000 (Aug 22, 2017)

*Full Volt pack in a 911 Frunk!*

Finally got to some EV work. I'm waiting on some replacement sheet metal parts, so I started making the mounts for the front battery. 

I decided to lay the long pack on its side with the mount in front to add some crash protection. There is about a 5 inch crush zone in front of it. I placed a support bar under the pack that I plan to put some rubber on so it is not simply cantilevered off the mounting plate.

The next largest pack sits behind it. I made some support bars to span the opening where the gas tank used to go. 

The small pack is mounted off a strut tower brace. It will need some additional support. I just have things tacked in for now to make sure it all fits. I'm thinking about running another bar across in front of it to support it like I did the long pack. Any other ideas?


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## Buggeee (Dec 11, 2016)

Mfor1k, I'm hoping to put my DC forklift motor in my '72 Super Beetle and, in the meantime, I drive a Volt to work. So, watching you put a Tesla motor in a 911 with Volt batteries is, well..., um. I guess what I am trying to say is that you are my hero. Lol. Seriously outstanding project. Props to Ferdinand. https://en.wikipedia.org/wiki/Lohner-Porsche


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## Jerhofer (Feb 10, 2018)

That upper brace will also serve to stiffen the shock towers. It will be very interesting to see how the weight distribution shakes out once everything is in place.


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## Ada Diamonds (Feb 9, 2018)

What about a second strut tower(ish) brace in front of the battery like this?


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## Ada Diamonds (Feb 9, 2018)

Also, I might recommend triangulating the strut tower brace on the firewall or tying it into a roll cage. In a frontal collision, you'd not want a few hundred pounds of battery intruding into the cockpit.

I lost a good friend when he crashed a glider and the battery hold down behind his head let go. Would have been a highly survivable accident otherwise.

JP


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## mfor1000 (Aug 22, 2017)

I like both of those ideas. Thanks!

I think I am going to do a removable triangulated brace at the front of that top pack. There are no attachment points on the pack there, so I'm thinking I'll do a halo around it with two rows of 1/2" tubing, then I can attach the brace to the halo. 

I also have been considering an x-brace that goes all the way down to the front, similar to how they did the 935's in this picture. I'll see how everything packages in there after I replace those fender mounting rails. My replacement rails should be here by the end of the week according to Fed-Ex.


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## Ada Diamonds (Feb 9, 2018)

mfor1000 said:


> I like both of those ideas. Thanks!
> 
> I think I am going to do a removable triangulated brace at the front of that top pack. There are no attachment points on the pack there, so I'm thinking I'll do a halo around it with two rows of 1/2" tubing, then I can attach the brace to the halo.
> 
> I also have been considering an x-brace that goes all the way down to the front, similar to how they did the 935's in this picture. I'll see how everything packages in there after I replace those fender mounting rails. My replacement rails should be here by the end of the week according to Fed-Ex.


That X-brace seems really smart to reduce risk of battery movement. Totally worth the ~5lbs of weight penalty to this shade tree mechanic


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## mfor1000 (Aug 22, 2017)

I finished replacing the fender rails on the front and tacked in the mounts for the 930 trailing arms. To figure out the position of the mounts, I attached a laser to a piece of angle iron that was clamped to the hub and shot that down the door sill. I measured over to the pinch weld to get a measure of the toe. I checked and those pinch welds are parallel, so they seamed like the best reference. The car is level on the lift, so I just set the camber level as well at ride height. Then I modified the add on mounts from AASE until everything lined up and tacked them in. 

I was trying to figure out the best way to locate the motor. I wanted to align the output shafts on the Telsa gearbox with the axles in the trailing arms. A friend of mine at work suggested making something that would bolt onto the CV flange of the trailing arms. So I 3D printed a set of flanges that I could insert a 1/2" aluminum tube into. The worked great and I was able to get the alignment really close with it. 

I did some quick calculations and realized that the rear mount could see up to 3000 lbs of load pulling down on it. So I decided to look at a few different simple structures in FEA to see how heavy I needed to go on the mount. I don't want to add any unnecessary weight, so I first tried a simple truss with 1" members. That was no where near strong enough. So I'm now using 2"x3"x0.083" members with full gusseting. 3/16" flanges for the attachment bolt. I got the upper member tacked in and the flanges. Now I just need to make the lower gussets and finish welding. Note that the motor was designed to be set into a subframe from the top. I had to get creative with a spacer to get clearance to be able to install the motor from the bottom. 

I'll probably work on the front mount first and get it tacked in as well before finish welding the whole rear. I've learned not to finish welding anything until the particular job is done, that way if you want to make a change, it is easy to cut out.


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## tylerwatts (Feb 9, 2012)

That's impressive work! Well done so far.


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## itchyback (May 28, 2014)

Thanks for sharing your solution for the rear mount. I am exploring solutions for a similar setup in my jaguar. I knew the original subframe would not be strong enough, but havent done the maths on how much strength i would need, I had considered 1.5-2inch tube as an option. For some reason i would like to try and keep it as a removable subframe, the realities of that idea i am yet to fully comprehend. 
I think i will borrow heavily from the original Porsche design. The trailing arm setup is easier to fit in then redesigning a double wishbone setup in such a tight space.


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## brian_ (Feb 7, 2017)

itchyback said:


> The trailing arm setup is easier to fit in then redesigning a double wishbone setup in such a tight space.


True. Semi-trailing arm suspensions (or aftermarket suspensions designed to fit in the same space) are in most of the conversions using a Tesla drive unit. Damien even removed a multi-link suspension from his BMW 8-series and replaced it with a semi-trailing arm suspension to make mounting the drive unit easier (or as he said, possible).

If your Jag is old enough to have the classic Jag IRS, using it would have another challenge not faced with the 911 suspension: those Jags use the halfshafts as part of the suspension (like swingarm suspensions, and some others such as Corvettes prior to the C5). I doubt that the Tesla drive unit wants to take lateral suspension forces through the axle outputs as this suspension would require, but maybe it could be made to work.


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## itchyback (May 28, 2014)

Indeed my jag does have the classic rear suspension. I was not aware of the issue with the drive shafts being an axially loaded until i had the tesla motor 
Now i just have to make it work. Trailing arms is my leading theory at this time. 
Damiens thread was very useful.


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## Ada Diamonds (Feb 9, 2018)

Dumb question:

Will wheelhop be a problem launching a Tesla powered 911? If so, you might want to consider asymmetric halfshafts (diameter, not length).

This Road and Track.com Corvette test says in part: The left-side halfshaft is larger in diameter than the right. Thus if an oscillation starts, it does so at different frequencies. http://www.viperclub.org/vca/threads/has-cadillac-fixed-irs-wheel-hop.611171/

I daily drive a 702rwhp CTS-V (2012, v2), and the v2 driveline is bulletproof well into the 9s.


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## mfor1000 (Aug 22, 2017)

I haven't seen 911's have much trouble with wheel hop, but that may be due to their rearward weight bias. Mine will be further forward than a stock 911, but should be heavier at the rear. That is an interesting idea to use different half shaft diameters so they don't have the same natural frequency. I might do that just in case. I'm planning to talk to these guys about the half shafts:

http://www.driveshaftshop.com/

They are just down the road from where I work and do excellent stuff.

I finished the front and rear motor mounts. The rear is a stronger variation of the FEA work I did earlier. The front mount bridges the torque tube and the shock crossmember. I did have to notch the rear seat pan area slightly to get a straight shot between them. I also gusseted it as well to be sure it can handle all the torque.

I'm waiting on the side motor mount part to come from Toyota. My motor didn't come with one and nobody put one on ebay. You can't buy Tesla parts without being a Tesla owner, but the Toyota RAV4 EV used a Tesla Drive Unit with what looks like the same side mount (A friend of mine has one). I looked up that part and was able to order it online through a Toyota dealer.


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## brian_ (Feb 7, 2017)

mfor1000 said:


> You can't buy Tesla parts without being a Tesla owner, but the Toyota RAV4 EV used a Tesla Drive Unit with what looks like the same side mount (A friend of mine has one). I looked up that part and was able to order it online through a Toyota dealer.


Clever!


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## brian_ (Feb 7, 2017)

Ada Diamonds said:


> Will wheelhop be a problem launching a Tesla powered 911? If so, you might want to consider asymmetric halfshafts (diameter, not length).
> 
> This Road and Track.com Corvette test says in part: The left-side halfshaft is larger in diameter than the right. Thus if an oscillation starts, it does so at different frequencies. http://www.viperclub.org/vca/threads/has-cadillac-fixed-irs-wheel-hop.611171/


An interesting read, but I am far from convinced. Wheel hop is primarily a suspension problem, aggravated by soft final drive unit mounting in an independent-suspension vehicle. If axle shafts are so torsionally soft that they are a problem, just stiffening them makes more sense to me than guessing at two torsional stiffnesses which might correspond to different resonant frequencies in a useful way.

If the halfshafts of the problem vehicles with unequal diameter shafts are of different lengths (and they do appear to be different in at least the CTS-V), I suspect that the difference is more likely to be compensation for the length difference, than tuning for different resonant frequencies.


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## mfor1000 (Aug 22, 2017)

The Tesla bushings are very soft. I can see how they could cause a wheel hop issue. 

I have a little experience with wheel hop from my Camaro. On Mickey Thompson SR's, it would wheel hop really bad. On Nitto drag radials, it doesn't even think about it when they spin. That's not why I switched, but certainly is a big bonus!

I'm planning to use some historic Michelin rally tires on the 911:

https://classic.michelin.com/en/Competition-Classic-Tyre-range/TB-15

From what I understand, they are very sticky (many don't like them because they pick up rocks so bad). Hopefully with their largest size, wheelspin won't be a huge issue.


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## brian_ (Feb 7, 2017)

mfor1000 said:


> I'm planning to use some historic Michelin rally tires on the 911:
> 
> https://classic.michelin.com/en/Competition-Classic-Tyre-range/TB-15
> 
> From what I understand, they are very sticky (many don't like them because they pick up rocks so bad). Hopefully with their largest size, wheelspin won't be a huge issue.


So 29/61-15, which is a weird old Euro size (29 cm tread width, 61 cm overall diameter, 15" rim) corresponding to 335/35R15.

In 1973 Road&Track published a road test of a genuine RSR with specs including a rear tire size of 260/600-15 (260 mm tread width, 600 mm overall diameter, 15" rim), which is a variation of the weird sizing indicating about 30 mm narrower tread width and slightly shorter height than the 29/61-15; hopefully the kit fenders are wide enough. The 26/61-15 (295/40R15) would be a closer match if the biggest ones don't fit.

The original rear wheels were 11" wide, which is compatible with the two largest sizes of the TB-15 tires.

The same article quotes 230/600-15 for the front, on 9" wide wheels: there's no exact match in the TB-15 range, but 23/62-15 (270/45R15) would match width (but is taller, just as the potential rear sizes are taller). Unfortunately there doesn't appear to be a TB-15 size for the front which is a bit wider to handle the greater front weight.


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## mfor1000 (Aug 22, 2017)

The '73 RSR has narrower fenders than the '74. That is one reason I decided to go with the '74. They originally came with 10.5" front and 14" rear wheels. 

The plan is to run the 26/61 on the front and the 29/61 on the back. There should be plenty of room for tires under those big fenders. Although I'm not going to order them until I have the fenders installed and can take some measurements. The additional diameter is actually helpful to fill out the wheel wells. The original size tires look a bit small actually on the car. If I could design my own tires for this (my old job), I would probably design something like a 24/62 for the front and a 31/63 for the rear.

I'm a little worried about steering effort with the big tires on the front. These cars didn't have power steering. I may have to pull some caster and sacrifice some lane stability on the highway.


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## brian_ (Feb 7, 2017)

mfor1000 said:


> The '73 RSR has narrower fenders than the '74. ...
> 
> The plan is to run the 26/61 on the front and the 29/61 on the back.


Excellent - the greater fender width certainly helps, particularly at the front. 

The reduced stagger suits the likely reduced rear bias of this car with its front battery.



mfor1000 said:


> I'm a little worried about steering effort with the big tires on the front. These cars didn't have power steering. I may have to pull some caster and sacrifice some lane stability on the highway.


Or just add electric steering assist, if you can still fit the unit in the steering column.


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## Ada Diamonds (Feb 9, 2018)

mfor1000 said:


> I'm planning to talk to these guys about the half shafts:
> 
> http://www.driveshaftshop.com/
> 
> They are just down the road from where I work and do excellent stuff.


Yep - if you work with DSS on the project, you're not going to be breaking axles any time soon


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## mfor1000 (Aug 22, 2017)

I finished the final motor mount last night and hung the motor this morning! It is nice to see it in there. 

I had to make a custom side mount for the motor. The stock one wouldn't clear the shock. I cut the bushing out of the stock mount and fabricated a new mount to wrap around the side of the motor. A piece of tubing with the right ID was found to press the bushing into. It will still be tight, so I plan to find a button head cap screw to give a little more clearance when the suspension is traveled.

One of the tricky parts about mounting this thing is that it was designed to be dropped in from the top. So there isn't clearance to raise it straight up into fixed mounts. The side mount is detached from the motor and pushed into it's mount past the mounting point. I have to tilt the front upward and get it into the front mount first, then push it forward, past it's mounting point to give clearance for the rear to be raised. Ounce the rear is clear, then it can be moved back. Then the side mount is positioned and bolted to the motor. A little tricky, but not too bad with a good transmission jack.

With the motor hung in place, the entire car was neutrally balanced on the rear lift supports. Because of this, I had to strap the front down so it didn't flip off the lift if i pulled down on the back while working on it...beware of that if you are mounting one of these in a light weight car.

I also tacked in the front upper battery mount. Plenty of clearance there, but I did have to mount it at a big of an angle. I plan to work on the rest of the rear battery mounts this weekend.


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## brian_ (Feb 7, 2017)

mfor1000 said:


> With the motor hung in place, the entire car was neutrally balanced on the rear lift supports.


An interesting coincidence.  With battery mass going about equally in front and rear, the current balance will give a good indication of final mass distribution.

It looks like the rear jack point is at or slightly ahead of the torsion bar tube. Do you know how far that is ahead of the rear axle line?


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## mfor1000 (Aug 22, 2017)

The rear jack point is about 26" ahead of the axle. The wheelbase is 89.5", so that means (if I did my math right) it is about 29/71% right now! Fortunately, the front battery packs are on average further ahead of the front axle centerline than the rears will be behind it. It also has the rear suspension on it with no front suspension. I also have a big heavy Tesla charger to put up front, so I'm hoping it is close to the original 40/60% when it is all done.

I think I've decided on the rear layout for the batteries...see pics

The largest rear battery is laid on it's side and angled up slightly to the rear. According to measurements, this should keep it about he same height as the rear valence. It will be installed from the bottom. 

The two other batteries will be installed through the decklid opening. The front is angled up slightly to give clearance for the motor to move around in it's rubber mounts. The rear is mounted as low as possible over the large battery. It looks to have good clearance to the decklid. I think I'll enclose the whole area around the batteries completely with sheet metal to keep it dry. I'll make a skid plate to go from the floor pan all the way to the rear valence to protect everything and also clean up the aero back there.


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## Ada Diamonds (Feb 9, 2018)

The way you have the battery behind the motor placed, you even have room for a diffuser! Wonder if this would fit/work?

http://www.clearmotorsport.co.uk/products/diffuser


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## brian_ (Feb 7, 2017)

mfor1000 said:


> The rear jack point is about 26" ahead of the axle. The wheelbase is 89.5", so that means (if I did my math right) it is about 29/71% right now!


Looks right to me! 



mfor1000 said:


> Fortunately, the front battery packs are on average further ahead of the front axle centerline than the rears will be behind it. It also has the rear suspension on it with no front suspension. I also have a big heavy Tesla charger to put up front, so I'm hoping it is close to the original 40/60% when it is all done.


It all sounds promising. You could calculate the end distribution reasonably closely, but at this point there doesn't seem to be a lot of room to change the design to make much difference...


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## mfor1000 (Aug 22, 2017)

I have the rear battery mounts in place now. I test fitted the upper batteries to make sure I had clearance. For the long pack on the bottom, I plan to replace the center coolant feed with some 90 degree end plates. Those are on the way. I plan to put in an additional support so the bottom pack isn't just cantilevered off the mounting plate. 

I will try to do something to aid the aero under the back of the car. I don't think I'll do the full strakes on a diffuser because they destroy the angle of departure for the car. There are some steep entrances to businesses around here and I don't want to drag them.


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## Ada Diamonds (Feb 9, 2018)

If I'm not mistaken, I believe you can break the Volt batteries down all the way into 'slices of bread' and build back up as you see fit.

You might be able to take the upper rear most battery, break it in half, and attach one half to the battery directly above the motor and the other half to the battery behind the motor.

That could give you better weight distribution and enough trunk space for a weekender bag or two, no?

Progress looks great!

JP


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## brian_ (Feb 7, 2017)

Ada Diamonds said:


> If I'm not mistaken, I believe you can break the Volt batteries down all the way into 'slices of bread' and build back up as you see fit.


Yes, but going down to the level of the polymer frames (which hold two cells each, or one per end frame in each stack) requires breaking the welded connections to the flexible tabs of the pouch cells. It has been done, but is not trivial.

The more practical approach in most cases is to go down to the module level: modules are electrically linked by bolted connections. As we discussed earlier in this thread, starting at post #20, the blocks used here are at the level to which the pack readily breaks down mechanically, and consist of two or three modules each.


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## mfor1000 (Aug 22, 2017)

The battery mounts are finished now. I had to create a truss to support the front upper battery. It is a very tight fit to the battery below, so I ended up using a bowed 3/16" plate to support the battery. I did some quick FEA to find it needed about a 4mm bow in the center to equalized the distribution across the battery. Outside of that it is a standard truss using 3/4" tubing. I have some HDPE sheet to put between the mounts and the batteries for insulation.

I added a support bar for the rear lower battery as well. Mounting the rear battery was a bit sketchy because of the angle. It wanted to slide off the wood board that I had bolted to my transmission jack even with the srap in place. I added a 1x1" to catch the groove in the side of the battery to keep it from wanting to slide off. No problems now.

A full trial fit of all the batteries and motor was then done to make sure there were no complications.


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## Ada Diamonds (Feb 9, 2018)

Nice!

I love that you put batteries on the right side in front and back to help offset the driver weight (I assume).

N00b question: Does vibration/NVH harm the batteries? IE does rigid mounting to the frame with no bushings or isolators somehow reduce the performance or longevity of the batteries?


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## Kevin Sharpe (Jul 4, 2011)

Ada Diamonds said:


> Does vibration/NVH harm the batteries?


It has no impact on the battery cells


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## Duncan (Dec 8, 2008)

Ada Diamonds said:


> N00b question: Does vibration/NVH harm the batteries? IE does rigid mounting to the frame with no bushings or isolators somehow reduce the performance or longevity of the batteries?


Despite Kevins disclaimer vibration WILL harm your cells!

If you rattle the hell out of them then they will die early 

As long as you keep the vibration levels down to below the levels in the OEM application you should be OK - how low are those? probably quite low a Volt is intended as a comfortable saloon car

My Device is a road/track machine - and I use it on the grass as well - so far so good - but I could be slowly killing my cells


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## Kevin Sharpe (Jul 4, 2011)

Duncan said:


> Despite Kevins disclaimer vibration WILL harm your cells!


None of the OEM batteries that I have seen employ anti vibration mounts and instead rely on solid battery enclosures to protect the cells. Some OEM's add thread lock to cell screw connections but most simply rely on the connection material properties and screw torque settings.

Vibration will not harm battery cells, electronics, or wiring when the battery enclosure is properly designed and manufactured.

Anyone who has any doubt about the strength of OEM batteries should watch this video;


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## Duncan (Dec 8, 2008)

So Kevin is saying that you can't harm cells with vibration?

There now Kevin the nice men with the funny jackets will be here soon to take you to a nice safe padded cell


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## Kevin Sharpe (Jul 4, 2011)

Duncan said:


> So Kevin is saying that you can't harm cells with vibration?


All of the EV's that I've owned in the last 8+ years have batteries that are solidly mounted to the vehicle and do not use anti-vibration mounts. This includes Tesla's, Leaf's, Outlander PHEV, Vectrix, and an ECO Quad (which does a great deal of tree pulling and off road work).

I'm aware of another ~30 car, truck and boat projects that do not use anti-vibration battery mounts.

Obviously, all systems that are intended for use in a vehicle are designed to withstand the vibration that they experience for the lifetime of the vehicle. The battery cells that we use are no different and do not require special protection.

One of my friends Ampera's has just passed 67,000 miles and has been used as a daily commuter for the last 6 years. It has a battery that is bolted securely to the vehicle


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## Emyr (Oct 27, 2016)

Duncan said:


> So Kevin is saying that you can't harm cells with vibration?


Not quite...



Kevin Sharpe said:


> Vibration will not harm battery cells, electronics, or wiring *when the battery enclosure is properly designed and manufactured*.


If you mount cells in machined aluminium racks, they will vibrate and wear through their pouches/casings unless they fit so tightly they can't move, in which case any deformation of the chassis which is transmitted into the battery casing will reach the cell...

Using silicone, polyurethane or firm closed-cell foam as part of your pack design is probably a good idea.


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## Kevin Sharpe (Jul 4, 2011)

Emyr said:


> If you mount cells in machined aluminium racks, they will vibrate and wear through their pouches/casings


That's a great example of poor battery design.



Emyr said:


> Using silicone, polyurethane or firm closed-cell foam as part of your pack design is probably a good idea.


None of the OEM's do this so why should we try and reinvent the wheel?


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## mfor1000 (Aug 22, 2017)

I did mount the batteries to the right to offset weight. The driver, controls, and the motor itself all add weight to the left. I hope I didn't go too far! 

As for the vibration, I've been thinking about that as well. I do have HDPE strips isolating the batteries from the metal of the extra supports on the horizontal mounted batteries. I did this for a couple reasons. One was vibration, although the HDPE is pretty stiff. The other was isolation in a crash. I wanted to reduce the chance of a metal bracket piercing a battery. 

The standard volt mounting racks do have thin rubber pads that go under the battery. I will put those back in place after everything is painted. I may also add thin rubber pads on the extra supports for the horizontal mounted batteries just to be safe.


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## dedlast (Aug 17, 2013)

Ada Diamonds said:


> N00b question: Does vibration/NVH harm the batteries? IE does rigid mounting to the frame with no bushings or isolators somehow reduce the performance or longevity of the batteries?


I don't think anybody is asking the Right question. The question isn't IF vibration will harm the cells, the question is How Much vibration does it take to harm the cells. Kevin seems to be saying that, as long as they aren't banging around or sliding back and forth, you should be good.

The example of wearing through the pouches is a good example of sliding back and forth too much. I think EV usage is fairly benign as a vibration environment, much more so than ICE vehicles.

Bill


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## Ada Diamonds (Feb 9, 2018)

IMHO, rigid mounted batteries in a chassis of a Volt/Tesla/Leaf/etc != rigid mounted batteries in a sports car with spherical bushings, high durometer poly or delrin bushings, etc. Especially if the sports car sees regular AutoX or HPDE use. The latter could have an order of magnitude more NVH than the OEM EV.

I'm not critiquing the 911's build at all, I'm just asking for my own edification as I'm in the early stages of researching a high performance toy myself. 

I've got a full track built 1969 Camaro with a 500rwhp small block that I'm considering going electric, and the suspension setup is such that I'd likely want to isolate the batteries somehow with motor mounts or cradle mounts between the chassis/rollcage and the battery racks.


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## electro wrks (Mar 5, 2012)

Although rare, problems with battery pack vibration, movement, and wear, can happen. Here's a recent example with Zero motorcycles: https://ultimatemotorcycling.com/201...al-short-fire/

In another area of concern, the Tesla Mod 3 has battery modules with over twice the length of the ones in the S and X. Let's hope the Mod 3 designers took into account the increased thermal expansion and contraction as it relates to possible material wear and fatigue.


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## mfor1000 (Aug 22, 2017)

Progress report...

The upper rear engine bay was closed in with sheet metal to eventually make the battery area waterproof. I'll seam seal it later when I'm sure I'm finished welding so it doesn't catch on fire! The rear area will also be sealed off to some sort of diffuser once the body kit arrives.

The water pump for the drive unit has been mounted. This is an EMP brushless water pump with CAN control. I'll dial it in to operate at peak efficiency with inlet and outlet pressures.

The charger, DC-DC converter, and the contactor box have been mounted.

Work has started on the sunroof delete panel. Some PVC pipe was cut to support the panel from underneath. I'm still trying to decide whether to weld it in or use structural adhesive. 

The bottom of the quarter panels were tacked back in place. I'll wait to finish weld and grind those until the body kit arrives.


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## mfor1000 (Aug 22, 2017)

more progress...

The 12V battery came in. It is a 40 Ah LiFePo4 battery from China with an integrated low voltage cutoff. I decided to put it in the back to help the weight balance of the car, although it isn't very heavy. 

I double checked the rear alignment and fully welded in the 930 trailing arm mounts.

I also received my Zeva smart pre-charge controllers. 

http://www.zeva.com.au/index.php?product=110

I have two and think I'll keep the motor and charger/DC-DC converter on separate circuits. That way I can turn on just the charger and DC converter when I want to charge without having the motor turned on for safety. 

I also ordered the J1772 socket and controller for it. The plan is to do a through the hood vintage style filler with this inside...


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## coleasterling (Feb 29, 2012)

Your LV battery looks interesting. Can you share where you purchased it?


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## mfor1000 (Aug 22, 2017)

I ordered the LV battery from China off Ebay...hopefully it works ok... Seems pretty well made.

https://www.ebay.com/itm/40B19L-12V...946707?hash=item1a4755ac53:g:0dEAAOSwpWBap36O


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## coleasterling (Feb 29, 2012)

mfor1000 said:


> I ordered the LV battery from China off Ebay...hopefully it works ok... Seems pretty well made.
> 
> https://www.ebay.com/itm/40B19L-12V...946707?hash=item1a4755ac53:g:0dEAAOSwpWBap36O


Thanks! Looks like a decent battery for the price. I'm sure some specs are optimistic, but hey, probably worth the risk.


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## mfor1000 (Aug 22, 2017)

The sunroof delete panel is bonding right now...it fit very nicely. I used 3m 8115 panel bond and #6 self drilling screws every 3 inches to clamp it. There was one spot where I couldn't get a screw in due to the underlying structure. There i was able to use a clamp. 

I'll leave it like this for a couple days to cure and then cut the screws off flush with the roof surface. 

The supports underneath just give it a little boost to the shape at the back, they probably aren't needed.


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## mfor1000 (Aug 22, 2017)

Sorry it's been a while. I've been restoring and accumulating suspension parts to put this thing back together. I've also been working on the braking system. Attached are some pics of the parts I've been refinishing. 

The brakes are off a salvaged Boxster. I chose them because they are inexpensive and after refinishing they look similar to the 930 brakes that were on the race cars. The calipers are actually stiffer since they are one piece. They won't allow quite as big of rotors as those race cars, but that shouldn't be as much of an issue with this car due to the regen. I used the Stomski racing adapters for the front. I bought another set of these and was able to modify them to work with the 930 trailing arms in the back as well.

The plan is to use a dual master cylinder setup with a balance bar and no booster. This keeps me from having to run a vacuum pump. I sized the masters pretty small to try to keep the pedal effort reasonable. I'll just have to balance that with their capacity and pedal travel to get something that works. Attached is a picture of the floor modifications necessary to accommodate it. I had to check clearance relative to the tie rods and it clears. The boots may rub a little at extreme travel. The pedal with the masters are being restored and I don't have a picture of it yet. I bought a used Wilwood pedal from ebay. 

In the picture you can also see the throttle pedal. It has a linkage on the back that I plan to connect to the EV West aluminum throttle position sensor, which is on the way.

I also ordered a brake pressure sensor. I plan to have the controller modify the regen on the motor in proportion to the front brake pressure. This way I can nearly turn off the rear brakes and get the maximum amount of regen available with out spinning out due to too much rear bias.


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## Ada Diamonds (Feb 9, 2018)

mfor1000 said:


> I also ordered a brake pressure sensor. I plan to have the controller modify the regen on the motor in proportion to the front brake pressure. This way I can nearly turn off the rear brakes and get the maximum amount of regen available with out spinning out due to too much rear bias.


Would it be possible to put some slack or elastic deformation in the linkage between the pedal and the rear master?

That way under light braking the rear calipers are not engaged at all (just regen), but you get progressive engagement of the rear calipers in a balanced way all to the point that you get front lockup with the correct amount of rear bias?

I owned a supercharged Gen 1 viper that had the OEM rear brakes of a minivan. That car was damn spooky as the brake bias was abysmal!
_______________

Given that you're using manual brakes, are you planning to run a fairly beefy return spring on the throttle? I'd think it would be a bit odd to have 10-25lbs of petal force to brake, but 2-3lbs of force for the 'gas,' no?

Great to see the build coming along well!


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## Kevin Sharpe (Jul 4, 2011)

mfor1000 said:


> I plan to have the controller modify the regen on the motor in proportion to the front brake pressure.


Chris has implemented something similar in his drift car project... you can lock the wheels when using regen alone


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## mfor1000 (Aug 22, 2017)

That's a good idea to maybe have some slack on the rear master. I could possibly put a spring on it with a certain amount of preload. Until I overcome that preload, the bias bar would only apply the front brakes. I'll think about that one. It might be fun to get the necessary amount of preload in that spring! There is a 5:1 ratio on the pedal and you'd likely want that preload to be overcome by around 30 lbs of pedal force...that means 150 pounds of preload in the spring...

I've also considered putting a paddle on the wheel for when I just want to apply more regen in a straight line. 

The Driveshaft Shop gave me the modified inner stub axles today. They wanted me to put them in and double check the measurements with a flange to flange measurement at ride height. So, I put the motor back in and took that measurement. We were going to reuse the inner CV's from the Tesla axles, but then I realized those type of inner CV's would make it impossible to remove the CV's without removing the trailing arm because the outers are in a deep dish. So, they cut and welded a standard 930 CV flange to the stubs so it could just be unbolted from both sides. The inner can be slid down and then pull the outer out of the dish in the trailing arm.

While I was at it I clearanced one of the bosses on the motor for the left rear shock. Please excuse the crusty old shock...I've had two ebay rear shock sales fail. I had to cut about 1/2" off the upper boss for the Tesla standard side mount. None of the threads are gone, so you could still use the standard side mount with a spacer later.


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## klokwerk (Jan 13, 2008)

Loving this project! And I'm so glad I found it.

I'll be going a similar route with my '89 964. Tesla Model S drive train and a 32 kWh battery. 

Keep up the great work because i'll be following right behind you!


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## mfor1000 (Aug 22, 2017)

klokwerk said:


> Loving this project! And I'm so glad I found it.
> 
> I'll be going a similar route with my '89 964. Tesla Model S drive train and a 32 kWh battery.
> 
> Keep up the great work because i'll be following right behind you!


It's always good to compare notes! Are you starting a build thread?


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## mfor1000 (Aug 22, 2017)

Kevin Sharpe said:


> Chris has implemented something similar in his drift car project... you can lock the wheels when using regen alone


I wondered if that was possible.


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## klokwerk (Jan 13, 2008)

mfor1000 said:


> It's always good to compare notes! Are you starting a build thread?


For sure! As soon as I actually start. Still in the planning phase. Planning and soon to be buying.

Definitely want to have it road mapped first before diving in. And right now I'm at a crossroads with a decision. I wonder if you've already decided this or not.

Do I try to complete the EV conversion in such a way that I could, if I wanted to, revert it back to ICE? The real decision is to cut or not to cut? 

The reason this is important is for two reasons. First is resell value. Second is battery placement. 

If I cut, no resell and no going back. If I cut, I can put the batteries any where I want. And right now I'm thinking under the car. Which means cutting the existing floor out, redesigning the framework to accommodate a battery pack etc.

If I don't cut, the car could be returned to stock (if I keep all of the parts) and sell it off to someone else one day.

Your thoughts?


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## mfor1000 (Aug 22, 2017)

klokwerk said:


> For sure! As soon as I actually start. Still in the planning phase. Planning and soon to be buying.
> 
> Definitely want to have it road mapped first before diving in. And right now I'm at a crossroads with a decision. I wonder if you've already decided this or not.
> 
> ...


I initially thought to try to make everything bolt in. However, I realized quickly that this would add a lot of weight and also slow things down tremendously. On these projects, I find my biggest obstacle is time. I have a normal job, so my time is precious. Also, if a project like this takes too long, it essentially expires. You'll end up with a car that you just feel like you need to redo because the technology has moved on. 

One other thing is that everything is reversible even if you cut and weld. All the structure I've welded in could be cut out and ground flat in a few weekends. I may have to purchase some replacement panels to weld in to make everything look original, but even that is not a big deal. Even if you remove the entire floor of the car, you could likely get a replacement.

I hope this helps...


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## jetdexter (May 30, 2018)

Sorry guys I know that this is becoming its own sub-topic, but I am in the same boat with a Tesla drive unit in a 911. Though I want to do a (high collector value) long hood narrow body 911. I am pushing back pretty hard on the idea that once restored, this car would be worth over a hundred grand. Cutting it all up to do this takes all that away. Even welding it all back takes away from value. (I too want to put the batteries in the lowest, most embedded positions possible for the best performance and customization).

My resolve for this is to find a roller with no matching motor and transaxle. Maybe a car that someone screwed with before. Besides, Ferdinand himself said "I couldn't find the sports scar of my dreams, so I built it myself." I loved my Tesla, and I have loved my 911s, but my dream car is the combination, so this has to be done.

Those are my thoughts...


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## mfor1000 (Aug 22, 2017)

jetdexter said:


> Sorry guys I know that this is becoming its own sub-topic, but I am in the same boat with a Tesla drive unit in a 911. Though I want to do a (high collector value) long hood narrow body 911. I am pushing back pretty hard on the idea that once restored, this car would be worth over a hundred grand. Cutting it all up to do this takes all that away. Even welding it all back takes away from value. (I too want to put the batteries in the lowest, most embedded positions possible for the best performance and customization).
> 
> My resolve for this is to find a roller with no matching motor and transaxle. Maybe a car that someone screwed with before. Besides, Ferdinand himself said "I couldn't find the sports scar of my dreams, so I built it myself." I loved my Tesla, and I have loved my 911s, but my dream car is the combination, so this has to be done.
> 
> Those are my thoughts...


Yeah. I sure wouldn't want to cut on one of the long hood cars in most cases. They have enough value that you can do a complete resto and maybe make some money. 

Mine was a '79 SC roller with rust that had been stripped of the drivetrain and interior. After blasting, I spent a couple months just fixing rust. After doing all that, I'm not shy about some additional cutting and welding! Also, being a '79 SC, it is not a crazy value car, especially since it didn't have the original drivetrain. Even though I got the roller cheap, putting it all back to original condition would cost far more than they are going for.

I'm just trying to build a fun car to drive to work anyway...no plans for selling it. Upgrades and modifications will keep me entertained by this car for a long time.

Hopefully you can find a car in similar condition...keep your eye on craigslist!


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## mfor1000 (Aug 22, 2017)

more progress...

The axles arrived from The Driveshaft Shop. They look great and fit nicely. At full droop, they do start to bind on angle, so I will probably have to put a droop limiter on it to stay out of that in case I get airborne! (poor Damien...) I did confirm that I can remove them easily now without taking a trailing arm off. 

I also finished the chassis side brake lines. I mocked up the front suspension to make sure the caliper adapters fit. I did have to trim the brake shields a little for these calipers since they are so much bigger than the stock SC ones. The rotors are the larger Carrera rotors. 

The aluminum potentiometer mount from EV West showed up and it works great. I needed the dual output potentiometer for compatibility with the drive unit. I just had to make a small mount for it. I also put in a very strong throttle stop just in case I get excited... The linkage is just mocked up for now. I ordered a better linkage. You'll see the brake pressure sensor and the brake pressure switches mounted behind the throttle pedal. I made sure to mount them so they wouldn't trap air.

I also tacked in the mount for the coolant pump for the front batteries and mounted the brake fluid reservoirs. You'll notice the additional firewall behind the top battery mount. I intend to add a seal to the hood above. That way if I do get a fire, it will take longer to get to the cockpit.


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## klokwerk (Jan 13, 2008)

The new axels do look great and your pedal setup is awesome.

What are you using for a brake booster? 

Keep up the great work!


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## mfor1000 (Aug 22, 2017)

klokwerk said:


> The new axels do look great and your pedal setup is awesome.
> 
> What are you using for a brake booster?
> 
> Keep up the great work!


Thanks, I'm going to try it without a brake booster. I'm trying to make the system as stiff as possible so I can use a small master cylinder for a big hydraulic advantage. If I don't like it, then I can always go back to the booster and get a vacuum pump.

I added a second return spring to the gas pedal tonight. There is a clock spring on the EV West mount, but I wanted a second one...if you lose your return spring on the throttle, that can become a very bad day!


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## Duncan (Dec 8, 2008)

Brake boosters are like power steering
We never used to need them!

In the olden days cars didn't have them and they drove just fine

Back in the 80"s I had a Lancia Spyder - great car lovely to drive
I had to go away on business in a company Ford Escort - not a patch on my Lancia

When I returned after four days and about 1400 miles I got into my Spyder - nothing worked!
The pedals would not move , the wheel would not turn and the gear lever was stuck

It took a couple of days before I was back used to driving the Lancia again!

I think what I'm saying is that if the brakes feel too heavy initially give yourself a bit of time before charging out and getting a booster

Modern cars spoil us - but the extra effort is worth while


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## brian_ (Feb 7, 2017)

Duncan said:


> Brake boosters are like power steering
> We never used to need them!
> 
> In the olden days cars didn't have them and they drove just fine...


Sure, as long as "just fine" means much slower steering, or in the case of brakes much higher pedal force. In the case of brakes there is another significant factor: drum brakes can be self-energizing, so the switch to much more responsive disk brakes required more hydraulic force, and thus either higher pedal effort or a power assist.

My Triumph Spitfire has quick non-assisted steering and effective non-assisted brakes with disks in front (but drums in the rear)... but it is a light car, and both more difficult to drive and inferior in performance compared to a car with modern steering and brakes.


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## Duncan (Dec 8, 2008)

brian_ said:


> Sure, as long as "just fine" means much slower steering, or in the case of brakes much higher pedal force. In the case of brakes there is another significant factor: drum brakes can be self-energizing, so the switch to much more responsive disk brakes required more hydraulic force, and thus either higher pedal effort or a power assist.
> 
> My Triumph Spitfire has quick non-assisted steering and effective non-assisted brakes with disks in front (but drums in the rear)... but it is a light car, and both more difficult to drive and inferior in performance compared to a car with modern steering and brakes.


Cobblers 
My Lancia was as responsive and handled and braked as well as any modern car - and it had discs all round
And MASSIVELY superior to a Spitfire!

The only time when power steering is actually useful for a car is parking and even then only if you are a 45kg weakling
Even a 45 kg weakling can handle non power brakes


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## Emyr (Oct 27, 2016)

Duncan said:


> Brake boosters are like power steering
> We never used to need them!
> 
> In the olden days cars didn't have them and they drove just fine
> ...


The Lancia Beta weighed 1000 - 1200kg, 997 GT3 RSR dry weight is 1220kg.

You don't expect the same speed or deceleration from a Beta though.


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## Duncan (Dec 8, 2008)

Emyr said:


> The Lancia Beta weighed 1000 - 1200kg, 997 GT3 RSR dry weight is 1220kg.
> 
> You don't expect the same speed or deceleration from a Beta though.


So the weights are very similar - so the steering should be about the same - actually lighter on the RSR as the Lancia was FWD

As far as the brakes are concerned the RSR will have HUGE discs compared to my Lancia - the Lancia had solid (not vented) discs that fitted inside a 14 inch wheel

So I would expect a similar "feel" but with much more braking power with the RSR


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## mfor1000 (Aug 22, 2017)

Looks like they fixed the old Thread! Here is an update...

I've been spending most of my time working on fitting the body kit. It will take a lot of work to make it fit well. I guess this is par for the course for a fiberglass body kit. 

While I was waiting for some glue to try, I finished the shifter modification to make it compatible with the HSR controller. Jason set up that controller such that you don't hold the button down for the drive state that you want, rather you just push it once. He says it would probably work if you hold it down, but it would prevent updating other things like regen...etc

I chose to use the 5th and reverse positions. These already have detents to hole the shifter in place. I built a gate to prevent the shifter from going to the other positions. The shifter passes by the appropriate microswitch for each position. It passes by the Neutral switch each time it exits drive or reverse. There is also a safety mechanism to prevent going from 5th to reverse on this shifter. I kept that. It is not really necessary because the drive unit will protect against that electrically, but I plan on leaving it for now.

I'll also include some of the body kit pics that I had started on the other thread since I thought this one was dead.


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## Ada Diamonds (Feb 9, 2018)

mfor1000 said:


> Looks like they fixed the old Thread! Here is an update...
> 
> I've been spending most of my time working on fitting the body kit. It will take a lot of work to make it fit well. I guess this is par for the course for a fiberglass body kit.
> 
> ...


Looking good! Is the body kit from GT Racing? What are the trouble areas?

Could you potentially work a mechanism to use 4th gear almost like a drift car's handbrake? That way if the shifter is in neutral you are in drive with no regen but as you move the the shifter down from neutral to 4th you get increasingly strong regen?

That way you could induce oversteer at will on turn in for sideways smiles?

It'd be pretty easy to build a safety lockout so you couldn't accidentally go from 4th to reverse. no?


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## mfor1000 (Aug 22, 2017)

From the rethread post:



sholland said:


> That's great to know. Can you tell me if the Driveshaft shop was cheaper than EVTV for the inner 930 CV stub?
> 
> http://store.evtv.me/proddetail.php?prod=Porsch930


It would be cheaper to have them modify the original axles if you already have some. If you do not, it is probably about the same as buying those custom ones from evtv. I'd just want to make sure the heat treat was right for the splines.


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## mfor1000 (Aug 22, 2017)

The body kit came from Poland. I had heard about many issues with the gt racing version. Although, this one is not without its problems. So far I've had to do a good bit of slicing and dicing to get them to fit properly. You could just slap it together, but then it would only look good from about 50 feet. I have quite a bit of work to do to glass up the slices and smooth it all out. At least it is the correct shape now and matches the bumper.

As for the shifter...It may be exciting enough without getting fancy...I'm might try that later Ada.


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## mfor1000 (Aug 22, 2017)

Progress...

I haven't posted much for a while because I've been powering through the bodywork. What a mess, but I can see the light. I have the body now good enough to continue. Everything now fits decent and looks like it will work. The quarter panels took the most work. I had to slice them and shift them up to make them match the bumper. They were a bit droopy. I sliced them and then reglassed them back together. Then I skimmed them and blocked with 80 grit. To finish them off for now I sprayed them with polyester high build primer. I'll let the body shop get it the rest of the way. I don't have the skills necessary to make it completely ready for paint.

I lined the panels that would be exposed to rocks from the tires with some Kevlar I had left over from drone building. They should be bullet proof now!

I've started mounting the radiators now. I bought a small Honda drag racing radiator that didn't work out. It was too thick. So I made a trip to the local motorcycle showroom with a tape measure. I think a radator from a Honda Shadow vtx750 will fit well in the quarter panels, so I ordered one of these from ebay. 

For the front, I mounted a 993 AC condensor on the left fender (future plans), and have ordered a small scooter radiator for the right fender. I think it will be sufficent for the front battery.

I plan to use the front opening just to feed the radiators in the fenders. I'll seal it off with a front splitter to the underbody. This will help the aero and improve the cooling in the fenders.


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## mfor1000 (Aug 22, 2017)

The low voltage harness and anti-roll bars arrived this week.

For the harness, I went with the Painless Wiring 26 circuit off-road harness. I really liked the small, waterproof fuse block. This is a much more modern harness than the original Porsche one. I've used their products before and always have been pleased with them.

For the anti-roll bars, I chose the Tarrett Engineering RSR replica bars. They had me sold with the double shear arms. I had to drill a few holes through the front tub for the front bar, but that was easy and everything fit will. They are a tight fit to the coil-overs up front, but I think they will work fine.


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## Duncan (Dec 8, 2008)

Hi
If you end up with a significantly lower Center of mass then you may not need any anti-roll bars

I have the fittings for anti-roll bars on my device but with it's very low center of mass I simply have not needed them


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## brian_ (Feb 7, 2017)

The Tesla drive unit is low, (as were the Porsche transaxle and engine), but given the battery pack locations I would be surprised if the end centre of mass is any lower than the stock vehicle.

It would be interesting to measure it, but without a "before" value for comparison there isn't much point.


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## electro wrks (Mar 5, 2012)

Duncan said:


> Hi
> If you end up with a significantly lower Center of mass then you may not need any anti-roll bars
> 
> I have the fittings for anti-roll bars on my device but with it's very low center of mass I simply have not needed them


This may be true for anti-dive also. In a careful look at the front suspension of a Model S, I could see very little anti-dive built into the geometry of the suspension arms of this low CofG(Center of mass, as you call it) vehicle. Also, some anti-dive might be built into the active suspension system

A large luxury car conversion, I looked at recently, has a lot of anti-dive built in its stock suspension geometry. With the heavy engine removed and a complete Tesla battery pack below the floor in this conversion, the CofG must be much lower and further back. I think the builders put in softer front springs to compensate for less weight on the front end. Also, excess anti-dive AIR can cause the front suspension to act as if it had stiffer springs. I wonder how the excess anti-dive in this case would affect bump-steer. Anybody have any insights if it would? The builders might be in for a handful on their test drives.


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## Duncan (Dec 8, 2008)

Weight transfer - side/side or front/back is simply

Acceleration x height of center of mass divided by the distance between the wheels 

So a wide/long car with a low center of mass will have very little weight transfer even in hard cornering or fierce braking

The normal issue is that the weight of the car sets the optimum spring rate - but with that spring rate it rolls too far in cornering

So you end up using anti-roll bars


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## brian_ (Feb 7, 2017)

electro wrks said:


> A large luxury car conversion, I looked at recently, has a lot of anti-dive built in its stock suspension geometry. With the heavy engine removed and a complete Tesla battery pack below the floor in this conversion, the CofG must be much lower and further back.


True for a front-engine to rear-motor EV conversion, but to repeat the obvious: this 911 does not have the battery mounted under the floor (and the engine was already in the rear in the original configuration).

Yes, typical production EVs - not just those from Tesla - have the battery under the floor and the motor(s) at axle level, which should lead to a low centre of mass; they essentially have a ballasted keel. It would be interesting to see centre of mass heights for them and comparable engine-driven vehicles, but this information is very rarely published by the manufacturers (although they all design with this height in mind and measure the result). Even Subaru who advertises a height advantage due to their opposed engine configuration never backs it up with data.

I was interested to discover in a search today that Car and Driver magazine started testing centre of mass height (which they and many others call center of gravity height) several years ago. In one article they reported the CofM height for a 2011 Porsche 911 GT3 as 17.4 inches. That's interesting, but without a measurement of this EV-converted 911, and a reference value for a corresponding 911 (not one from decades and generations of changes later), it doesn't help.

In some Car and Driver test which I have found, the 2013 Tesla Model S Signature Performance is reported with a center of gravity height of 18.0 inches. For comparison, the first few hits in a search for C&D's spec pages:

2011 Porsche 911 GT3: 17.4 in
2014 Chevrolet Corvette Stingray: 17.5 in
2013 Tesla Model S Signature Performance: 18.0 in
2013 Subaru BRZ: 18.0 in (low and sporty, with "boxer" engine)
2017 Acura NSX: 18.5 in (hybrid exotic sports car)
2014 Aston Martin Vanquish: 19.0 in (extreme luxury/performance coupe)
2016 Audi TT: 19.5 in (sporty coupe based on typical compact car platform)
2014 Infinity Q50S: 20.5 in (conventional sedan)
2016 Honda Civic Touring: 21.0 in (conventional small sedan)
2018 Honda Accord Sport 2.0T: 21.5 in (conventional mid-sized sedan)
2012 Audi A6 3.0T Quattro: 22.0 in (somewhat low luxury/performance sedan)
2013 Ford Fusion SE Hybrid: 23.0 in (conventional sedan, but with hybrid battery)
2015 Honda Fit EX: 23.0 in (tall but more conventional car style)
2017 Maserati Levante S Q4: 26.5 in (luxury/performance car in tall "SUV" style)
2016 Lincoln MKX Reserve AWD: 26.5 in (luxury/performance car in tall "SUV" style)
2015 Jeep Renegade Limited 4X4: 27.0 in (small but tall "SUV")
2017 Honda Ridgeline: 28.0 in (unibody AWD pickup truck)

The list suggests that among vehicles without half a ton of battery, ride height (lots of space under those "SUV" things) and body height are as significant as powertrain: the Audi TT has a completely conventional engine standing upright, and the fit has a similar powertrain to the TT; the 911 has a boxer engine while the Corvette has a V8, but their centre of mass height is the same.


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## mfor1000 (Aug 22, 2017)

Yeah, I probably hurt the CG on this conversion with all the batteries I wasn't able to mount at floor level. The original 911 was very efficient in this regard with its flat-6 engine configuration. 

I worked on the rear diffuser. I'm mocking it up with plywood for now. I'd like to use a Tegris like material. If that doesn't work out, I may laminate some plywood with some Kevlar I have left over and go with that. Maybe later on I'll get fancy and mold one.

In the pics you'll see I was able to remove the lower part of the bumper and bring the diffuser up further. This should help drag and lift.

My roll cage came in also. It is a safety devices cage. I hope it fits!


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## mfor1000 (Aug 22, 2017)

jsimonkeller said:


> I continue to follow this thread and it has been so helpful and instructional with my work to convert a 1978 Targa SC into a Tesla911  Some photos below.
> 
> I had a question about the axles since I could not tell from your build whether you encountered this same issue. Because my car was a roller, the existing 911 axles on the car have taken a beating and are toast and I am planning on replacing them.
> 
> ...


I would be surprised if existing Porsche axles are the right length. That would mean that the Tesla drive unit output flanges just happen to the the same width as the Porsche trans-axle. The odds of that seem small, but once you get your flanges, you could measure them and see if you can find a similar measurement from a trans-axle. Maybe you'll get lucky, but you will still need different CV's on the inside and outside. I think 930 flanges are different than the 911 SC flanges. So you would need axles that had 930 flanges on the inside and SC flanges on the outside. 

I put turbo trailing arms in my car, so I have 930 flanges on both sides. I did this because of the large offset the wheels will have due to the big rear flares. The turbo trailing arms have stronger bearings for this. That install was not for the faint of heart and I would not recommend putting them in unless you are doing the big flares. 

My recommendation would be to call The Driveshaft Shop. Once you have the drive unit mounted, then you need to put the rear suspension at ride height and measure from flange to flange. Tell them you have 930 inners and measure the bolt circle on your outers to confirm their size. They can make you a custom set of axles...should be around $1200.


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## mfor1000 (Aug 22, 2017)

Progress update:

The rear undertray/diffuser was remade in 1/4" ABS plastic. It should provide good protection for the motor and batteries and clean up the aero. I was able to get a 4'x8' sheet of the stuff from a local supplier. It cut just like plywood.

The roll cage was installed.

The two rear radiators were installed in the quarter panel vents. I ended up using radiators for a Kawasaki ZX1000. I found a slim 8" fan to put on them as well from Mishimoto. At some point I'll modify the vents to fair them into the radiators for better flow.

I started on the front undertray. Again, I am mocking it up in plywood, then I'll cut some 1/4" ABS for the final part. I'm waiting on the front battery radiator. I didn't like any of the ones I have gotten so far. Hopefully this next one will work.


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## Hathaway (Sep 5, 2018)

It has some rust at the rear attachments of the front*fenders*and at the rear bases of the*doors. From what I've read, these are typical spots. This is where water and dirt get trapped. It also has some at the base of the*windshield, especially on the left side. I did a decent amount of cutting on the left*fender*attachment per the picture. I ordered another*fender*attachment*panel*since the lower*part*of it would be difficult to fabricate. I'm going to make my own*patch*panel*for the inner*part*I cut out. Fortunately, the inside of the frame and the rocker were in excellent condition.*


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## mfor1000 (Aug 22, 2017)

More Progress...

Installed the charging port. There will be a hole cut through the hood to expose this. Typical RSR stuff, but should look pretty cool. I'll need to seal it and put a drain in this eventually since it will be exposed to weather.

I finished the shroud around the lower rear battery and started putting batteries in the car again to work on wiring. 

I've also installed the ignition and figured out the wiring. I'm planning on the first position of the ignition (accessory) will turn on the computers, charger, and DC-DC converter. Ignition will activate the ZEVA precharger to power up the motor.


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## mfor1000 (Aug 22, 2017)

jsimonkeller said:


> Great photos and thanks for the updates!
> 
> How much room is there between the backside of the motor and the rear 911 bumper? I will be planning out my battery locations this week and wondered how much clearance you have after the Tesla motor goes in?


There is about 14 inches from the back of the rear drive unit mount to the inside edge of the engine bay. Then there is about another 7 inches to the bumper if you go under the back of the engine bay.


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## Ada Diamonds (Feb 9, 2018)

Really impressive progress. Your talent is spectacular!

It's hard to tell from the photos: does the cage have any tie ins to the front suspension? IE does the cage protect your feet from the batteries in a front end impact?

What's your wheel plan? Are you going with OEM repos, a modern tribute, or something 21st century? 15" or bigger?


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## Ada Diamonds (Feb 9, 2018)

One potential suggestion to help you with packaging your various fluids and coolers:

Laminova, a Swedish company, makes very efficient fluid-to-fluid heat exchangers that are used by Koenigsegg, F1 teams, etc.

http://www.laminova.se/technology/heat-exchanger

If you struggle with cooling the front batteries, it might be better to route the coolant rearward and use a Laminova HE to transfer the waste heat to the primary cooling system.


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## brian_ (Feb 7, 2017)

Ada Diamonds said:


> What's your wheel plan? Are you going with OEM repos, a modern tribute, or something 21st century? 15" or bigger?


I thought that I remembered a discussion of this... yes, 15", see post #67 and following.

That's the tire size (so the diameter and the approximate width), but I don't recall a discussion of wheel size.


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## Ada Diamonds (Feb 9, 2018)

brian_ said:


> I thought that I remembered a discussion of this... yes, 15", see post #67 and following.
> 
> That's the tire size (so the diameter and the approximate width), but I don't recall a discussion of wheel size.


Awesome! After seeing the Singer Williams 911 at the Quail, I fell in love that style of wheel with a deep dish to fill a big flare.

JP


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## mfor1000 (Aug 22, 2017)

There is no cage tie-in to the front suspension. The cage stops at the dash. I've considered adding some tubes, but it will probably be good like it is and will be easier to package if there aren't tubes everywhere. Not to mention, I really want to get this thing running, so I'm focusing on wiring right now.

Here is a link to the wheels:

https://fifteen52.com/products/forged-2pc-outlaw-003?variant=33806647373

15x10's up front and 15x12's out back.

The tires are Michelin Classic competition TB15's. I already have those...the wheels should arrive in the next few weeks. There is a 6-8 week lead time on them.

Attached is a picture of the rear electrical box. The rear battery positive will come into the switch and then jump to the big fuse. On the other side of the fuse it will be joined with the positive from the front pack. It then goes on to the GV200 contactor and on to the motor.

The contactor is controlled by a ZEVA precharger. The 4 relay board is going to get swapped out for a custom set of relays and fuses. That board activates the relays with a pull to ground and that isn't going to work with my harness. I'll probably use it elsewhere. I need 4 relays back there for the two coolant pumps and the two radiator fans.


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## mfor1000 (Aug 22, 2017)

It's Alive!

https://youtu.be/LM-_3IqEUUg

Sorry, unedited, skip to 50 seconds in...


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## mfor1000 (Aug 22, 2017)

I'm using the HSR Controller from Jason Hughes:

https://hsrmotors.com/products

The problem with it not hitting neutral is due to my micro switch setup on the shifter. I just need to adjust the position of the neutral switch so it hits it longer when coming out of drive. The controller works great.


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## mfor1000 (Aug 22, 2017)

Wiring progress. I just need some more cable to finish the HV wiring. The BMS's are also hooked up. A friend of mine came up with a CAN shifter so I can run both BMS's on the same bus. We are still debugging it, but that should suffice for now. He is also working on a 4 CAN bus board with all the other EV goodies built in. That should simplify things.

I am a little concerned with the 4/0 cable pulling out the studs from the batteries. I'm going to do everything I can to support them to prevent this.

The BMS wiring harnesses also need to be shortened. I'll do that later, I just have them coiled up for now.


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## mfor1000 (Aug 22, 2017)

Wheels and tires finally arrived...big relief that they fit!

I also scaled the car using some really old scales a friend gave me. Says 2800 lbs so far...those scales are not very accurate, but that's around what I'm expecting.


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## Jerhofer (Feb 10, 2018)

Here's a couple more shots that he sent me.


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## Keplus4 (Oct 1, 2018)

Sounds like an amazing starting point to me!!


mfor1000 said:


> I previously had a thread for a 944...but I had an opportunity to buy a 911 roller. It needs fenders, so why not put some big ones on it so I can get giant rear tires to hook up all that Tesla power...
> 
> Attached are some pictures of the car and the picture from the maker of the body kit.
> 
> The plan is still to use the two Chevy Volt battery packs. There is more room in this than the 944!


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## mfor1000 (Aug 22, 2017)

Maiden Voyage!

Excuse my appearance...been thrashing on this thing...it is pretty fast!

https://youtu.be/sQbKBapxK4U


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## Keplus4 (Oct 1, 2018)

Absolutely beautiful 😊. Torque monster, that pull looks like it could pin you to the seats effortlessly. Congratulations on a job well done!


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## Jerhofer (Feb 10, 2018)

Here's another view.


https://www.youtube.com/watch?v=39_fRAmbzio&feature=youtu.be


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## mfor1000 (Aug 22, 2017)

Made some progress on plumbing the battery cooling. It gets pretty complicated with the valve for heating. I'm waiting on some elbows and other parts to finish that up.

Someone asked about wiring the BMS's for CAN. Attached is a photo of the connector. The blue and white/black wires are used for CAN. The Red and Orange/yellow wires are 12V positive, the black wires are ground.

So I decided to work on the software this weekend. I couldn't turn down the motor coolant pump because it runs on a different CAN bus speed than the BMS and I only have a couple of CAN buses to work with. So to trick it, once a second I switch that CAN bus speed to 250 kbps, send the message, then set it back to 500 kbps to continue reading the BMS's. This kinda works...every once in a while it doesn't quite make it and the pump speeds up for a second to it's default speed. A friend of mine is working on a 4 CAN bus board so I can just keep it separate.

Attached are some photos and the latest code...


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## mfor1000 (Aug 22, 2017)

Also here are the heaters and temperature sensors housings for the rear. I'm using the ones out of the Chevy Volt battery. They work great as bulkhead connectors. A friend at work welded a barb on the other end so I wouldn't have to use the weird OEM connectors. I'm driving the heater with a small gigavac contactor.

I'm struggling with reading the amps from the BMS. If anyone knows the codes for that, I'll take all the help I can get. Right now I'm just estimating discharge using the stuff from the HSR controller. That will miss all the accessory drain.

Here is how I'm decoding it right now and it doesn't work that well:

0x210: // Pack Voltage, Main Pack Amps

BMS1_packVolts = (((incoming.data.bytes[0] << 8) | incoming.data.bytes[1]) >> 4) / 8.0; // Volts
BMS1_packAmps = ((int16_t)((incoming.data.bytes[3] << 8) | incoming.data.bytes[4])) / -50.0; // Amps


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## swoozle (Nov 13, 2011)

mfor1000 said:


> So I decided to work on the software this weekend. .....
> 
> Attached are some photos and the latest code...


Very nice. That looks like a pi display. What GUI are you using?


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## mfor1000 (Aug 22, 2017)

jsimonkeller said:


> Thanks for the photos on the heat exchange system. Some questions:
> 
> 1. What product are you using for the radiator grill in the photo and how did you determine the size needed? Only one for the entire system?
> 
> ...


For the radiators, I chose the largest ones that would fit in those locations. They are from a Kawasaki 1000 cc motorcycle. They should have plenty of cooling for the much more efficient electric motor and the batteries. There are three of them in the car. The one in the front is a different shape, but also from a 1000cc motorcycle.

I have 3 separate pumps for the system. One for the front battery, one for the rear battery, and a larger brushless pump for the motor.

I'm using the stock temperature sensors from the volt packs for them. They are connected to the BMS and I can read them over CAN. The motor has internal sensors that I also read over CAN. 

I do have a control logic for the motor cooling pump. I have it changing through three RPM levels based on the highest temperature observed in the motor. It will not run when the ignition is turned off.

I haven't dealt with the battery control system yet. My initial plan is to operate them manually with switches until I sort that out.


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## mfor1000 (Aug 22, 2017)

swoozle said:


> Very nice. That looks like a pi display. What GUI are you using?


I'm using a 4D systems display using their Visi-Genie IDE software. It is very easy to use.


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## kevinlaz (Sep 22, 2018)

Hello,

Thank you for documenting your project and listing your code on the 944 build thread. You mentioned you now read temperature of volt pack via the volt bms. In the posted code I don’t believe it had this, would it be possible to post code section related to reading the temperature sensors on the battery pack?

Below link was helpful to me for volt relay wiring. It also discussed current readings from the volt pack (can code capture during acceleration and graphing of the values that changed). The author might be good contact to see if they figured out the scaling.

http://www.nkirkby.net/derptruck-and-the-struggle-for-ev-legitimacy/

In terms of relay and pre-charge turn on sequence code, I found below code link helpful. We have used this code and hardware and using it to control the stock volt relay control box and pre-charge for our system on/off. It can also be used for control of aftermarket relays like you have. 

https://github.com/DrJeffCooke/TesL.../master/relays_command_1/relays_command_1.ino

https://youtu.be/WgBjHdMv-78

We are also using the 4d systems display, have you figured out how to get a better looking font for the display, similar to below link? I believe maybe by using String digit for display?

https://youtu.be/uPKq1yhbO6o

Great work.

Best regards,
Kevin


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## mfor1000 (Aug 22, 2017)

Thanks for the links Kevin. I'll check those out. I need to sort out the amperage scaling for sure.

The cooling system for the batteries is finally completed. I was just waiting on a couple elbows. It seems to work fine. I tested the re circulation valve and heater system.

The fiberglass headlight buckets were not good and would not properly retain the headlights. I cut them out and bonded in a set of steel headlight buckets and all is well now. Lights are installed and hooked up. I'm using LED's to conserve power and they work great.

I'm borrowing a Brusa charger from a friend until he finishes the Damien board for the Tesla charger.

With all the lights hooked up and all but the door glass in place, I put the plate on it and started driving it. It is a little chilly without the door glass, but great fun! This car is a rocket. I took some data and I should be able to analyze it to see how fast this thing is. It feels like the fastest car I've built off the line. I've probably driven it 50 miles this weekend. I drove it to vote, to a Guy Fawkes bonfire, auto parts store, and KFC to pick up some dinner! It took a lot of discipline on the drive back from KFC not to spill the drinks all over the place!

Here are some pics...


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## tylerwatts (Feb 9, 2012)

You know it so I'm agreeing, that thing is awesome! Well done and congrats.


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## Jerhofer (Feb 10, 2018)

I am the father. Last Sunday I both rode in and drove the car. It is a rocketship. The first time he floored it, expletives poured out of my mouth. He is thinking 0-60 is near 2.0 seconds, which, considering the speed of the Tesla S and the fact this this car is 1500lbs lighter, is probably realistic. 

This was my first experience riding in an electric car. Other than the acceleration, the other big thing I noticed was the regenerative braking. Neither Matt or I applied the physical brakes very often. I was braking way too early for stops as I underestimated the braking force.

Another pleasant surprise was how docile the car is. The accelerator pedal is very progressive so driving the car in traffic was as easy as driving a car with a very good automatic transmission. I am incredibly proud of what Matt has achieved here and in awe of his skills. 

He is a guy who needed to become a mechanical engineer as he has been figuring out how things work since he was a child. Back in the eighties and early nineties when I was very heavily involved in the Porsche club, to ward off the winter doldrums, we used to hold slot car races at our house each winter. This was supposed to be a fun event, but many of the members were autocrossers and racers who were very competitive. We had winner's and loser's brackets set up. Many of these people, mostly guys, wouldn't take a drink until they were eliminated. And some of these guys were serious drinkers!!

Matt, whose age was still in single digits during the first of these events, would spend months preparing his car. We had bought him a very small lathe and he would unwind the motor, balance the armature, and rewind it. He would spend hours adjusting the magnets and searching for the right tires. And he would spend months practicing. Come race day, he would blow all of the adults away...every year!! To distract him, guys would yell at him, wave their hands in front of his face, etc. None of this fazed him because he had his car so well set up, he could floor the throttle all the way around!! It was great fun for him, not so much for the contenders. Matt's in the striped shirt.








A couple weeks ago I attended the Charlotte Cars & Coffee. There was an electrified old beetle there. It was an interesting car and was parked near a group of Tesla owners. I struck up a conversation with a Model 3 owner who absolutely raved about his car. While I didn't drive it, he did let me sit in it to get a feel for the interior. There is tons of room in the rear trunk and rear seat area. The frunk is decent size but not huge. Overall, the car is larger than photos led me to believe. That thought was shared by the owner. 

While I have been a Porsche and sports car guy for nearly fifty years, I surely could see myself owning a Tesla. I like to buy low mileage used cars so maybe in a couple years there will be a Model 3 with my name on it.


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## mfor1000 (Aug 22, 2017)

I drove it to work for the first time (~25 miles)... It drove great...was a littly chilly with no side windows. I had to stop once because the windshield fogged up when I passed through a valley. 

I ended up giving amusement park rides to all the gearheads. This thing seriously scared my boss. 

After getting it back home and inspecting it I found that the tires were throwing up so many rocks they are damaging the radiators. I ordered some screen from Mcmaster Carr to protect them.

Here is a picture of it charging behind our building by one of our old mule cars. And the new 911 T badge...


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## mleebert (Aug 6, 2018)

Jerhofer, thanks for your post I really enjoyed it. Fun story and a great demonstration of a proud father.

I've been following this thread with admiration. I may have even seen both of you in a video of one of the drives. I hope you post more.

mfor1000, thanks for the inspiration to continue my own project. Cheers!


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## mfor1000 (Aug 22, 2017)

The racing seats are mounted now. They look much better. I'm going to see if I like the racing interior. It is not as convenient, but is much safer and holds you in place better when slinging the car around.


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## hbthink (Dec 21, 2010)

*86 911 Cabriolet AC Powered*

I really miss my 86 Cabriolet it was very fast pretty good balance but a bit heavy

Azure Dynamics DMOC 645 & AC90
100 x 90aha Voltronix
Elithion BMS
Locked into 3rd gear

could cruise on so cal freeways for 100 miles or so

sad to say but now I drive a leaf. Miss it greatly was taken apart and put back as an ICE. 911s worth a lot here in So Cal but not so much with electric.

Steve


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## mfor1000 (Aug 22, 2017)

I made some progress on the details.

The wipers are working now, not parking properly, but working. 

I have some of the guages working. The speedo and temperature/oil pressure guages were first on the list. For the head temperature, I am sending stator temp. For the oil pressure, I'm sending in inverter max temperature. That guage went from 0 to 140, so that was a decent range for the inverter. I'm driving them off pins from the Arduino DUE. I found a library to allow easy frequency changes for the speedo. Attached is the latest code for the Arduino that I'm using.

Attached are pictures of the guages and the circuits/calibrations used. The circuits were given to me by an EE friend. They work great. I had to adjust the speedo calibration for the tire size, now it reads very accurately according to the GPS on my phone. 

You'll see I also put some black speaker carpet on the top of the dash with some rubber trim to hold it. This is actually how the race cars did it back then to reduce glare. It was pretty bad with the white dash. The rubber molding isn't the same as what they used. I'm going to try to find something that looks decent. I might break down and put a regular dash in it some day.

I've been driving it whenever I can. It is a pleasure to drive. I have many car friends that are seriously considering electric for their next projects after driving it.

Also attached is a little graphic my dad sent me about car projects...


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## mfor1000 (Aug 22, 2017)

Tesla Charger is working!

Thanks to Damien, Tom, and my friend who put the components on the board for me!

I used this board from Damien:

http://www.evbmw.com/index.php/evbmw-webshop/tesla-bare-boards/tesla-gen-2-charger

Then this version of the software from Tom:

https://github.com/tomdebree/Tesla-Charger

One thing that the instructions don't talk about is that it is expecting PIN A3 to be pulled high on the left connector. Tom told me this is the interlock for a BMS. I disabled that logic for now. I'm still sorting my BMS's out so that I can use it.


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## jackbauer (Jan 12, 2008)

Great to see it up and running. Well done


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## BlueHorizon (Nov 27, 2018)

Seriously impressive work here and has actually inspired me to take on my own "Porsla" EV build. Bought a 1980 911 SC roller (no transmission / engine) with a decent body off eBay that was delivered a few weeks ago and am currently stripping it down. And yes, it has a damned sunroof to contend with too!

Anyway, being in the software field, I don't have your skills when it comes to fabrication / mechanical engineering prowess so I'm going to have to rely on friends / local experts to help out on several fronts. However, thought I'd ask you a few basic questions based on reading the thread a few times:

1) Did you ever look at the Tesla motor cradle as a way of possibly mounting the motor to the chassis?

2) Likewise with the motor cooling, did you consider just taking a bunch of stock Tesla components versus leveraging your own?

3) Anything you'd do differently based on what you've learnt? 

All the best,

Garry


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## Moltenmetal (Mar 20, 2014)

Amazing project and result! You have a totally unique car there- worth every second of all that work!


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## mfor1000 (Aug 22, 2017)

BlueHorizon said:


> Seriously impressive work here and has actually inspired me to take on my own "Porsla" EV build. Bought a 1980 911 SC roller (no transmission / engine) with a decent body off eBay that was delivered a few weeks ago and am currently stripping it down. And yes, it has a damned sunroof to contend with too!
> 
> Anyway, being in the software field, I don't have your skills when it comes to fabrication / mechanical engineering prowess so I'm going to have to rely on friends / local experts to help out on several fronts. However, thought I'd ask you a few basic questions based on reading the thread a few times:
> 
> ...


Hi Garry,

My motor didn't come with the cradle, so I'm not sure if it would work or not. I do know it is a very tight fit and it would be very lucky if works. Especially since it is designed for a much different suspension system than the 911. You will need some pretty serious fabrication for the mounts. There is a lot of load on them. 

For cooling, I'm still evaluating my current setup. It seems fine for cool weather, but I might need more in the summer. I'm considering dedicating both rear radiators to the motor and figuring something else out for the rear battery. The batteries don't seem to need as much cooling, but that too could change in the summer. The Tesla uses the AC system to get additional cooling in the system. The main issue I'm seeing is that the desired temperature is low compared to an IC engine. The cooling energy required isn't that much due to the efficiency, but at those low target temperatures it is hard to get rid of (need delta T!). That's why Tesla uses the AC unit. I may end up doing the same thing. The other thing that would be nice would be to separate the cooling on the motor. The stator can be run much warmer than the inverter. Ideally, I'd cool the stator conventionally and the inverter with an AC system.

It is still a bit early to decide what I'd do differently. So far things are working pretty well. The biggest trouble I had was with the first cooling pump I used in the back. It was too powerful and I was having a hard time controlling it because of some CAN issues. It damaged itself so I ditched it in favor of a conventional Bosch 12V brushed pump. It is much quieter and seems to work for now.

The biggest surprise is how the car drives. I originally anticipated it being a brute and thought that a race car interior would be fitting. It is extremely fast, but also civilized. The speed is smooth and effortless. The race car interior just seems like a waste and doesn't fit the personality of the car at all. Because of that, I'm going to get rid of the cage and put a full interior in it after paint. It will just be a very nice car to drive to work.


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## brian_ (Feb 7, 2017)

BlueHorizon said:


> 1) Did you ever look at the Tesla motor cradle as a way of possibly mounting the motor to the chassis?


The Tesla subframe is so specific for the Tesla's suspension and for the mounting points to the Tesla body that it's hard to for me imagine that it would be less effort to adapt it to the 911 than to start from scratch.


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## BlueHorizon (Nov 27, 2018)

Appreciate the fast response.. So cooling will definitely be a concern for me as here in Texas we'll have months of 100F+ days to contend with. 

Few more random questions as I'm still planning my build and want to get your insights:

1) What did you end up using for the brake pedal? FWIW I'm aiming to end up with no clutch pedal, just brake & accelerator. Will use a button pad to select drive modes.
2) Did you leave the stock emergency brake in place?
3) I know the Volt batteries are LG Chem. However, for ease of placement around the car did you look at the stand-alone LG chem batteries? (like this)


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## mfor1000 (Aug 22, 2017)

For the brake pedal I went manual with a Willwood pedal and master cylinders. I did this to keep it simple with no type of booster. I used very stiff monoblock calipers, so I can go pretty small on the master cylinders and keep the effort down. Right now it is ok, but I'll probably go a step smaller still when I tear it apart for paint. The effort is still a little high.

I did leave the stock emergency brake. It is very good and would be hard to beat. You really need it with a Tesla motor since there is no park.

I haven't seen those standalone batteries. That might be a nice way to go if they aren't too expensive. Battery packaging is definitely a challenge in this car.

I've been driving the car a good bit lately. I drove it to the painter to discuss and we seem to be on schedule for February.

I also drove up to @wk057's (057tech.com) new shop in Hickory, NC. It is about 50 miles and the car made it with no trouble. I recharged there to be sure while I talked with Jason. He has a great new building with lots of room! It was very educational to talk with him. He knows his stuff. He answered many questions I had about the controller I bought from him. It has been working great.

I put the tail on the car to see how it looks (see pictures). I like it better than I thought I would. It is pretty outrageously large. Kinda like an upper bumper! I'm going to do a little research to see what it does to drag on the car. Let me know what you think...


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## brian_ (Feb 7, 2017)

mfor1000 said:


> I put the tail on the car to see how it looks (see pictures). I like it better than I thought I would. It is pretty outrageously large. Kinda like an upper bumper! I'm going to do a little research to see what it does to drag on the car. Let me know what you think...


The flattened Beetle - I mean 911 - body design is hopeless aerodynamically. The rear slope is too steep to work as a tapered tail, but it has no way to breakaway airflow cleanly. The solution is a spoiler of some sort, part way down the rear slope. While 911 turbos had a "whale tail" largely to house the intercooler, and in race vehicles it is there to reduce rear lift, something at around the beltline is the way to reduce drag. The lift reduction and drag reduction are related - the spoiler reduces the lift and the corresponding induced drag.

Someone published a table of drag (and lift) values for various 911 configurations in Rennlist. Comparing drag values with and without the whale tail for otherwise the same car shows that it reduces drag.

A huge whale tail might overdo it in an attempt to produce downforce, but it will likely still be better for drag than no spoiler/whale tail at all. This is one just extended horizontally - at a guess I doubt this would harm the drag reduction benefit.


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## brian_ (Feb 7, 2017)

BlueHorizon said:


> 2) Did you leave the stock emergency brake in place?


When I saw this I wondered why there would be any question, since the change from the Porsche engine to the Tesla motor doesn't change the need for some sort of emergency brake, and the change from the Porsche transaxle to the Tesla transaxle doesn't provide any kind of park function.



mfor1000 said:


> I did leave the stock emergency brake. It is very good and would be hard to beat. You really need it with a Tesla motor since there is no park.


That makes sense to me... and I had no idea what the "stock" emergency/parking brake would be on this car ('79 911SC? RSR? Would they be the same?). I just did a quick search, and it appears to be a drum brake inside the hat of the disk brake rotor; I hate this design, because it has maximum complexity and is a pain to work on, but it is the traditional solution for a parking function with fixed-body calipers.


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## BlueHorizon (Nov 27, 2018)

Brian, I was curious about the emergency parking brake from a perspective that you could program an electronic one to trigger via a button as per some of the other controls. Example here

Now if your 12v battery dies however.. 

Anyway, I'll follow the same path of putting a regular handbrake in although garnished with a nice handle.


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## brian_ (Feb 7, 2017)

BlueHorizon said:


> Brian, I was curious about the emergency parking brake from a perspective that you could program an electronic one to trigger via a button as per some of the other controls. Example here
> 
> Now if your 12v battery dies however..


Ah, E-Stopp... stock brake, but electric actuator pulling on the cable. I've seen these before; they seem like a solution for a car without a conventional lever (or one in which the lever is used for a hydraulic handbrake instead... but I assume we're not rallying or drifting in this case). In a car with an available lever, this just seems like all the disadvantages of a conventional system (mechanical cables) plus the disadvantages of a typical electric brake (dependence on power, electrical/electronic failures).

I suppose if it set automatically when drive power is shut off and the vehicle is stationary, that might avoid an embarrassing roll-away error, given that the Tesla transaxle has no Park function , but a warning light and/or beeper would be about as effective .


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## mfor1000 (Aug 22, 2017)

The internal drum parking brakes seem to work the best of all that I've used. They are self-energizing and much more powerful for the same amount of cable effort than a caliper. The Porsche design is particularly good with a great mechanical advantage.

As for an electronic activation, I'm not keen to add that complexity. Not to mention it would be difficult to find a good place to put it.


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## mfor1000 (Aug 22, 2017)

brian_ said:


> The flattened Beetle - I mean 911 - body design is hopeless aerodynamically. The rear slope is too steep to work as a tapered tail, but it has no way to breakaway airflow cleanly. The solution is a spoiler of some sort, part way down the rear slope. While 911 turbos had a "whale tail" largely to house the intercooler, and in race vehicles it is there to reduce rear lift, something at around the beltline is the way to reduce drag. The lift reduction and drag reduction are related - the spoiler reduces the lift and the corresponding induced drag.
> 
> Someone published a table of drag (and lift) values for various 911 configurations in Rennlist. Comparing drag values with and without the whale tail for otherwise the same car shows that it reduces drag.
> 
> A huge whale tail might overdo it in an attempt to produce downforce, but it will likely still be better for drag than no spoiler/whale tail at all. This is one just extended horizontally - at a guess I doubt this would harm the drag reduction benefit.


Thanks for the link. Very interesting...wow, 0.421 CD is terrible...oh well, not going to be a hyper-miler! Of course I did not really plan on that with the wide tires anyway. It's only 25 miles to work...


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## Ada Diamonds (Feb 9, 2018)

If packaging is a concern one idea to throw out is to use a Laminova water to water heat exchanger to move heat from one system to the other.

http://www.laminova.se/

You can adjust how much of the flow goes through the exchanger to control how much heat you put into the system with the radiator.

That way you could move heat from the hotter system to the cooler system and then have a greater heat differential at the radiator to better remove heat.

___________________

(I lost a friend a few years back who crashed a glider. It was a relatively mild, survivable crash; however, a battery hold down failed and the battery fatally struck him in the head) 

Unless you plan to use the rear seat, why pull out the cage, given the risk of very heavy batteries entering the cockpit in a frontal or rear collision?

There are plenty of pro touring builds out there with nice interiors and solid roll bars or roll cages. You cage is a bolt in, no?

Cheers,
Jason


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## brian_ (Feb 7, 2017)

mfor1000 said:


> Thanks for the link. Very interesting...wow, 0.421 CD is terrible...


Yes, even for the 1970's! It's amusing, for someone who is not a Porsche owner, to read the comments in that discussion defending Porsche with convoluted logic about available technology, when in fact it simply never was a shape designed for aerodynamic performance. It's just an evolved Beetle, because the traditional shape is very important to buyers; that's not right or wrong, it's just the way it is.


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## brian_ (Feb 7, 2017)

mfor1000 said:


> The internal drum parking brakes seem to work the best of all that I've used. They are self-energizing and much more powerful for the same amount of cable effort than a caliper. The Porsche design is particularly good with a great mechanical advantage.


While I have never had (or heard of) an issue with excessive cable force being required with parking calipers, there's also no reason to change from an effective design that you like.


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## mfor1000 (Aug 22, 2017)

Ada Diamonds said:


> If packaging is a concern one idea to throw out is to use a Laminova water to water heat exchanger to move heat from one system to the other.
> 
> http://www.laminova.se/
> 
> ...


That is an interesting thought with the heat exchanger between the battery and motor cooling systems. 

I'm not too concerned with the batteries coming through the rear firewall. The structure back there is pretty decent 

The cage is a bolt in, but really makes the rear of the car almost unusable. (it is now the only storage space) There have been several times I've wanted to put something back there and had to snake it between all the bars and the fixed seats. It is also nearly impossible to clean the back window right now. I'd have to make some sort of rag on a stick to do it because access is so restricted. It also limits the seat movement. I'm a bit tall and would like the seat to go back another inch or two than what is possible with this cage. If I do keep it, I might make some modifications to make it more livable.


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## mfor1000 (Aug 22, 2017)

It's time to start tearing down for paint. It is hard to tear apart a good running car like this! I've been driving it quite a bit and it works really well. I took it to Cars and Coffee in Charlotte and got pinned down at the car for two hours answering questions! 

Before tearing down, I'm taking pictures and marking everything to make it easier to reassemble after it gets back from the body shop...here are some of the pictures...


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## klokwerk (Jan 13, 2008)

Such an incredibly clean installation! So glad this has turned out as well as it has. 
I have to get off my bum and get my project going! 

What are your plans for paint and that interior?


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## mfor1000 (Aug 22, 2017)

klokwerk said:


> Such an incredibly clean installation! So glad this has turned out as well as it has.
> I have to get off my bum and get my project going!
> 
> What are your plans for paint and that interior?


Thanks for the kind words. The plan for the exterior is to replicate what most 3.0 RSR's were like from the factory. Many were Grand Prix White, which is a kind of older looking white (not blinding like the new ones). I think I'm also going to go single stage so it isn't too shiny. I prefer that older cars have older style paint. I had an old Camaro that I had painted with a modern base-clear paint and I thought it seemed a bit out of place. Attached is a picture of a Grand Prix White RSR.

For the interior I plan do keep it simple. I've decided to ditch the roll cage and racing seats in favor of some recovered stock seats and a full interior in black. I think I'll go with a high quality leatherette to avoid the shrinking and maintenance of real leather. I'll also do some cloth inserts in the seats. I prefer that because it breathes better and holds you in place better without the big bolsters on the seats. I found a fabric that looks like they could have used it in the 70's in these cars and it will add a bit of color. In the attached pictures you'll see that I took the sample and stuck it in the racing seats just to get an idea how it will look.

I'm also going to dynamat the whole thing so it is really quiet. It should be a nice car to drive to work!


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## mfor1000 (Aug 22, 2017)

All ready for paint. I stripped it down completely. Sanded all the interior and bottom surfaces. I also made some ducts for the quarter panels for the radiators. 

It is off to the painter...Adam Nicholson at Backyard Legends of NC. 

https://www.instagram.com/backyardlegendsnc/?hl=en


He does incredible work on 911's... I can't wait!


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## mfor1000 (Aug 22, 2017)

More pictures...


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## mfor1000 (Aug 22, 2017)

And more pictures...I know these are helpful sometimes when you are trying to do a similar project...


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## brian_ (Feb 7, 2017)

mfor1000 said:


> And more pictures...I know these are helpful sometimes when you are trying to do a similar project...


I have no intention of ever doing anything like this with a Porsche... but I still appreciate the images!  Fascinating.

This extensive set of images showing the final result of the fabrication, before paint so it is clear what is original and what was added, should be educational for anyone who is thinking "I'll just install a Tesla motor in the back, which should be easy..."


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## mfor1000 (Aug 22, 2017)

Paint Update!

Adam and his team at Backyard Legends are making great progress on the paint. They are doing an incredible job. Here is his instagram link:

Backyard Legends

The car should go to the upholstery shop this week to get the headliner installed. Then it will come back to me to put everything else back in it. 

I can't wait!


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## mfor1000 (Aug 22, 2017)

More pics...


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## Tremelune (Dec 8, 2009)

Laughter-inducing torque; I love it! Very impressive build.

I'll be building a Tesla-911 in my mind for the next few years, so I'm watching everyone else's build with interest. I'm taken aback by how much work was done to the rear for yours (moving the trailing arm mounts, super serious motor mount). Would all that be necessary if you weren't putting batteries back there?

My "plan" was to fab up a subframe/bracket for the Tesla motor using the existing motor and transmission mounts, leaving the trailing arms mounted to the stock location. Is there something preventing this from being simple? Would the Tesla motor fit between the hubs of a narrow body 911?

The Tesla builds stand out due to performance, of course. It's not as compelling to install an AC50 while keeping the transaxle around...


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## brian_ (Feb 7, 2017)

Tremelune said:


> I'm taken aback by how much work was done to the rear for yours (moving the trailing arm mounts, super serious motor mount). Would all that be necessary if you weren't putting batteries back there?


If I understand the early posts correctly, the suspension modification (specifically the mounting point relocation) was unrelated to the EV conversion; it was part of making this car more like the RSR.


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## mfor1000 (Aug 22, 2017)

Brian is correct. The only reason I put the turbo trailing arms on there is because I wanted to run the really wide tires with a large negative offset. The turbo trailing arms stick out further and have much stronger bearings. If you're building a narrow body 911, there is no need to upgrade to these arms. Everything should fit just as well. 

The reason I went really beefy on the motor mounts was because of some calculations and quick FEA that I did. Also at that time @jackbauer had just bent his initial mounts on the Panzer. This thing pulls down on that back mount really hard and pushes up on the front. If you make a bolt in structure, make sure that it can take it. I went with a weld in structure because it should be stiffer and lighter than what can be done with a bolt in. If I ever want to switch back to ICE, it would take me a few days to cut it out and grind things flat again. I didn't remove any of the existing mounts. I still consider it removable, albeit with some sparks...

I made some progress, the suspension, brakes, batteries, motor, half shafts and about half of the wiring harness is back in...


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## mfor1000 (Aug 22, 2017)

It's all back together! I've been driving it today. Everything seems ok. I've been dialing in the AC, the Brake bias, and the radio...the Speedo is still fighting me for some reason, but I'll get some help with that. I forgot how fast it was!

The pictures don't do the paint job justice. It is way more shiny than in the pictures. 

The seats are pretty wild, but they make me smile. They add a bit of color to an otherwise monochromatic car...


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## BlueHorizon (Nov 27, 2018)

Looks amazing!! Congratulations on reaching the finish line on the build. Very inspirational. 

Just out of interest, did you manage to get the original speedometer hooked up and working?


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## mfor1000 (Aug 22, 2017)

BlueHorizon said:


> Looks amazing!! Congratulations on reaching the finish line on the build. Very inspirational.
> 
> Just out of interest, did you manage to get the original speedometer hooked up and working?


I had the original speedo working great, but then one of the chips inside died. A friend of mine reverse engineered it and got it running with an Arduino Teensy LC. I’m struggling with the communication to that board right now from my main board that gets the info from the drive unit. Hopefully my friend can help me with that as well.


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## TargaTuesday (Jul 4, 2019)

FYI, there is a company that makes an under dash box with short speedo cable for classic cars. Uses GPS for speed and is great for engine swaps, tire/wheel swaps, or final drive changes as it allows for accurate speed on the stock speedo no matter how the driveline is modified. Might be the perfect solution here.


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## mfor1000 (Aug 22, 2017)

TargaTuesday said:


> FYI, there is a company that makes an under dash box with short speedo cable for classic cars. Uses GPS for speed and is great for engine swaps, tire/wheel swaps, or final drive changes as it allows for accurate speed on the stock speedo no matter how the driveline is modified. Might be the perfect solution here.


Thanks for that, but it doesn't use a cable speedometer. I'm just having some communication issues between my main VCU and the little board I have controlling the speedo.


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## Jerhofer (Feb 10, 2018)

My son Matt made his official debut with the Porsche at this past Sunday's Cars and Cappuccino in Charlotte. It was placed with the featured cars, both because of its uniqueness and to provide publicity for Adam's company, Backyard Legends, which painted the car. Adam was there to help Matt place the car. It looked spectacular and was the hit of the show!! 

Matt and I spent about three hours answering questions about the car. A local builder of outlaw Porsche's asked Matt if he would be interested in replicating the car as he felt he could sell them for significant money. That gentleman stopped by a couple of times to talk to Matt to let him know he was very serious.

The general opinion I heard was that it was very professionally done and had a very finished look. Adam's spectacular paint was a big plus as the fit and finish of the bodywork is first class. As you can probably tell, I am very proud of my son. This was a huge project that he aced.


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## znitz (Sep 23, 2012)

I have been following this incredibly nice work, and I am very impressed. 👌💪
Please keep us updated of your future work, because, I think many of us out here will love to hear more from you.


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## riba2233 (Apr 29, 2015)

This is absolutely amazing, pretty much my dream car


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## Mick_D (Aug 2, 2019)

Hey Matt, I'm inspired. How are you insuring this thing?


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## mfor1000 (Aug 22, 2017)

Mick_D said:


> Hey Matt, I'm inspired. How are you insuring this thing?


I’m insuring it with a stated value policy.


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## Mick_D (Aug 2, 2019)

No mileage or usage restrictions? I've looked into those, most of them say I can't drive it to work or more than x miles a year. But thanks!


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## brian_ (Feb 7, 2017)

Insurance depends greatly on location. What is available in one place (province, state, country) may not be available in another, so without the location, specific insurance arrangement information may be misleading.


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## Mick_D (Aug 2, 2019)

Matt, I want to do this, and I'm ready to commit to the Tesla drive unit and setup. an we talk offline about what it'll take?


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## mfor1000 (Aug 22, 2017)

Mick, check your private messages. 

I’ve been driving it quite a bit and it is a lot of fun. One of the car shows I went to generated this:

https://www.instagram.com/p/B0YtXKbAMAL/?igshid=1at8ufheb29ps

The drag racing crowd had some pretty funny responses...


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## Mick_D (Aug 2, 2019)

I appreciate it, really looking forward to hashing out details and getting going.


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## mfor1000 (Aug 22, 2017)

https://youtu.be/-QdbyQ40Y8U

This was entertaining...


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## Mick_D (Aug 2, 2019)

Very nice! What was that other car?


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## BlueHorizon (Nov 27, 2018)

Matt, I'm working through my 1980 SC conversion and looking at the rear trailing arms. I know you went with 930 versions to cope with the additional stress but doesn't that require quite a lot of modification to fit onto a regular SC?


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## Mick_D (Aug 2, 2019)

I'm not Matt, but I can say with authority that the standard control arms for the 911 will work, and you don't have to use the 930 arms. All you have to make sure of is to let the machine shop making your drive shafts know which arms you are using, and make sure you take accurate measurements so the shafts are the right length.


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## BlueHorizon (Nov 27, 2018)

Thanks Mick. I know the regular ones will fit, but was thinking more about the longevity as the 930 ones are stronger. Having said that, I'm not using the performance motor (just a standard 85 S motor) and am not looking to have the world's fastest classic 911, just something that drives smoothly and is still peppier than the original.


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## Mick_D (Aug 2, 2019)

They will last as long as any cage or cradle you'll weld up to hold the motor, I am certain. I don't think Porsche changed the 930 arms due to lack of strength, but to change the geometry enough to deal with the massive boost after lag that caused the back end to dip when the turbo finally kicked in. No lag with an electric motor!


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## mfor1000 (Aug 22, 2017)

It does require pretty serious modifications to run the 930 trailing arms. The inner leg is quite a bit shorter. There are some RSR conversion brackets to weld on for the inner pivots. I mounted the outer, held ride height with a rod, and lined the toe and camber up with the lower door pinch weld with a laser on each side. Then tacked then in place. After confirming, I removed the trailing arms and fully welded the brackets. I also triangulated them. It is not for the faint of heart.


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## mfor1000 (Aug 22, 2017)

The bearings in the 930 arms are much larger and the CV flange is larger. The bearings are larger to deal with the large offsets with the big fenders. The larger CV flange can take the big 930 CV’s that can handle more torque. The rear jacking is also slightly different. It should have more anti-squat.


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## brian_ (Feb 7, 2017)

BlueHorizon said:


> Matt, I'm working through my 1980 SC conversion and looking at the rear trailing arms. I know you went with 930 versions to cope with the additional stress but doesn't that require quite a lot of modification to fit onto a regular SC?


As Matt explained, it's mostly the stress of the wide tires and their outset position (of the RSR style conversion) that were the issue. If staying with stock bodywork and roughly stock tire sizes, I can't imagine wanting to go to the effort of changing the suspension... especially to end up with essentially a tweaked version of the same design (still just semi-trailing arms).


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## BlueHorizon (Nov 27, 2018)

So I'm building a 911 ST which means I am having the front and rear wheel arches widened and will have large tires both back and front. 

As the car is undergoing rust repair right now, won't be able to tell exactly how wide the rear tires will be until we are at the stage to test fit the wider rear arches. 

FWIW here's the kit I bought: https://www.design911.com/Restorati...-Kit-Porsche-911-ST-Widebody-Look/prod133418/


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## mfor1000 (Aug 22, 2017)

I don’t think you need the 930 bearings for an ST conversion. Your offset won’t be that bad with SC arms. The larger CV’s may be nice to have, though. How much power are you planning to run?


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## BlueHorizon (Nov 27, 2018)

Well it's a standard model S motor and I'm still debating which batteries to hook up to it (leaning towards LGChem) so realistically nothing more than 300hp.


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## mfor1000 (Aug 22, 2017)

Talk to the guys at:
https://www.driveshaftshop.com/

They can find some CV’s that will live. You should be ok with the smaller ones as long as they are good quality and you don’t put super sticky tires on the car.


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## Mick_D (Aug 2, 2019)

mfor1000 said:


> Talk to the guys at:
> https://www.driveshaftshop.com/
> 
> They can find some CV’s that will live. You should be ok with the smaller ones as long as they are good quality and you don’t put super sticky tires on the car.





I sure hope you're right, I'm using stock CV's and street tires


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## jetdexter (May 30, 2018)

mfor1000 said:


> For the radiators, I chose the largest ones that would fit in those locations. They are from a Kawasaki 1000 cc motorcycle. They should have plenty of cooling for the much more efficient electric motor and the batteries. There are three of them in the car. The one in the front is a different shape, but also from a 1000cc motorcycle.
> 
> I have 3 separate pumps for the system. One for the front battery, one for the rear battery, and a larger brushless pump for the motor.


Matt, I've been following this build for the last couple of years as I have been working on my BMWTesla coupe. Your work has provided a lot of inspiration to me as it has many others. 

I see that you used a 3 speed pump and motorcycle radiator. Is there a chance you could shoot me the model of your pump? 

_Also_, I wonder what fluid you are running, and what type of tubing/hose you are using. 

I am driving my car now locally and very much enjoying it. Extremely quick, but very well behaved. I had a lot going against me as I wanted to fit 14 Tesla modules for 200+ mile range. I also used Jason's controller setup as I believe he is doing a great job of controlling in comparison to the other more generic options currently. 

Thanks in advance if you have any input for me. Feel free to PM me if it would cloud up this thread.

Paul


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## mfor1000 (Aug 22, 2017)

I started with a Fancy EMP CAN controlled pump, but burned it up because of trouble controlling it. I switched to a 1 speed Bosch intercooler pump with a relay and that works great. Simple is good...

https://www.summitracing.com/parts/bch-0392022002


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## BlueHorizon (Nov 27, 2018)

Do you have any details on the radiator? Just looking up Kawasaki 1000cc radiators and wasn't sure on what dimensions you settled on as there as various models of Kai 1000cc bikes. 

Example: https://motopartshop.com/products/motorcycle-radiator-for-kawasaki-z-1000-abs-2014-2018?variant=31160048320561&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=CjwKCAjw3-bzBRBhEiwAgnnLCvqxa0JtB_CySWurJejAnXecLscyQkmwjFoWWrdVqR7AaC2X6my88xoCBA4QAvD_BwE


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## jetdexter (May 30, 2018)

mfor1000 said:


> I started with a Fancy EMP CAN controlled pump, but burned it up because of trouble controlling it. I switched to a 1 speed Bosch intercooler pump with a relay and that works great. Simple is good...
> 
> https://www.summitracing.com/parts/bch-0392022002


Thanks a bunch, that looks perfect.


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## mfor1000 (Aug 22, 2017)

BlueHorizon said:


> Do you have any details on the radiator? Just looking up Kawasaki 1000cc radiators and wasn't sure on what dimensions you settled on as there as various models of Kai 1000cc bikes.
> 
> Example: https://motopartshop.com/products/motorcycle-radiator-for-kawasaki-z-1000-abs-2014-2018?variant=31160048320561&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=CjwKCAjw3-bzBRBhEiwAgnnLCvqxa0JtB_CySWurJejAnXecLscyQkmwjFoWWrdVqR7AaC2X6my88xoCBA4QAvD_BwE


That's the one I'm using. It was fine last summer in 100+ degree temps too with only an 8" fan on it.


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## jetdexter (May 30, 2018)

That’s the radiator I ordered as well. 

Hey are you running G48 coolant at 100%? That’s what I see being used and I believe what Tesla uses. Thought I would ask you as well! 

Sorry for the 1000 questions.


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## mfor1000 (Aug 22, 2017)

Yes, G48 coolant.


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## brian_ (Feb 7, 2017)

jetdexter said:


> Hey are you running G48 coolant at 100%?.


If by "G48 coolant" you mean something like ZEREX™ G-48® Antifreeze/Coolant... then absolutely do not use this undiluted. It is a concentrate, intended to be diluted approximately 50:50 with water, regardless of whether the application is an engine or an electric motor. If you are using a ready-mixed dilution (which is also available), then you use that straight, but just make sure that you are not using a concentrate without dilution.

All of these "G48" coolants are Glysantin® G48® by BASF; BASF sells it as a concentrate or ready-to-use mix, and various automotive fluid supplier rebrand it, some still as a concentrate and some after diluting it.

All of this is true of any glycol-based coolant. Glysantin is an ethylene glycol product (like most automotive coolants), with specific corrosion control additives.


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## jetdexter (May 30, 2018)

Thanks guys!


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## Nev Payne (Nov 16, 2019)

Hi, there, I'm reasonably new to all this EV stuff, but smitten already, i have worked with a guy on here to help build his Tesla boxter already and being an air cooled 911 fan and lucky to own a few and a custom fabrication shop, its about time I converted one of mine,Now I'm sure you have probably posted this answer several times, but do you know the finished overall weight of you car at all, would be intrigued to see what it weight??
Awesome work and Killer car may i add


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## mfor1000 (Aug 22, 2017)

Nev Payne said:


> Hi, there, I'm reasonably new to all this EV stuff, but smitten already, i have worked with a guy on here to help build his Tesla boxter already and being an air cooled 911 fan and lucky to own a few and a custom fabrication shop, its about time I converted one of mine,Now I'm sure you have probably posted this answer several times, but do you know the finished overall weight of you car at all, would be intrigued to see what it weight??
> Awesome work and Killer car may i add


Thanks for the kind words. It weighs 2900 lbs.


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## Duncan (Dec 8, 2008)

Hi Wantex
All of that is pure garbage - simply scams to extract money from the gullible


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## Tremelune (Dec 8, 2009)

I believe Wantex is the scammer and we are the marks...


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## brian_ (Feb 7, 2017)

wantex is an obvious scammer, spamming the forum with his crap. Duncan, please delete this jerk.


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## Duncan (Dec 8, 2008)

Wantex has been moved to the loony tunes over unity thread


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## alexbeatle (Jul 28, 2020)

brian_ said:


> If by "G48 coolant" you mean something like ZEREX™ G-48® Antifreeze/Coolant... then absolutely do not use this undiluted. It is a concentrate, intended to be diluted approximately 50:50 with water, regardless of whether the application is an engine or an electric motor. If you are using a ready-mixed dilution (which is also available), then you use that straight, but just make sure that you are not using a concentrate without dilution.
> 
> All of these "G48" coolants are Glysantin® G48® by BASF; BASF sells it as a concentrate or ready-to-use mix, and various automotive fluid supplier rebrand it, some still as a concentrate and some after diluting it.
> 
> All of this is true of any glycol-based coolant. Glysantin is an ethylene glycol product (like most automotive coolants), with specific corrosion control additives.


Do you use distilled water to dilute to 50:50?


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## brian_ (Feb 7, 2017)

alexbeatle said:


> Do you use distilled water to dilute to 50:50?


Yes, any glycol coolant is diluted with water; distilled is ideal.


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## alexbeatle (Jul 28, 2020)

brian_ said:


> Yes, any glycol coolant is diluted with water; distilled is ideal.


Perhaps a side question, but can nylon or polypropylene or polyethylene hose fittings handle diluted G48? Any special requirements?


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## brian_ (Feb 7, 2017)

alexbeatle said:


> Perhaps a side question, but can nylon or polypropylene or polyethylene hose fittings handle diluted G48? Any special requirements?


There are lots of chemical compatibility charts available online, and all of those polymers appear to have excellent compatibility with glycols, but it might make sense to look for this information from BASF.


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