# 1974 BMW CSE



## jetdexter (May 30, 2018)

_This blog is broadly written to speak to car enthusiast, electric car fanatics, friends and family, and that person who got bored on the internet one day and stumbled upon this blog. I will try my best to be too technical, too simple, to colorful and too plain since pleasing everyone is impossible anyway._

*Finding the Right Coupe*








I searched nationally for a good amount of time for the right car at a fair price. Because I want to convert it to electric, I was hoping to find a roller. Something with it's original motor and transmission missing, so that I could feel a little better that I wasn't the first person to cause harm to the collectable originality of the car. My car would certainly have rust, but I wanted to avoid a rolling rust museum. The overall condition of the car did not need to be high, but finding one as original as possible, and with as much of the trim intact was very desirable.

I can not and will not unpack the mysteries of the collector car market and it's currently obscene values of certain cars. Many cars from the 70s and 80s are getting very hot, so what you could get for just $5k a few years back is suddenly costing $20k. In looking for my coupe I wasn't as concerned with value, but I did want to do the best I could to avoid getting caught up in all the hype.









In the end I came a very interesting 1974 3.0 CS through a very off-the-radar listing (really helping with the aforementioned over-valuation hype). It was close by in San Diego. It is a European market car, imported to the US in 1994. This is interesting for a couple of reasons: First, it was driven for many years by actual Europeans, most likely full-throttle on the Autobahn. Second, it means that it has the lovely small bumpers that by 1974 all US market cars did not. They received park bench units that hung well into the next county. What really pleased me is that she is a sunroof model. Those that know me know that if my cars don't have a sunroof, a convertible or a targa, I will likely find a saw nearby and take it to the roof. (You should have seen my 1978 VW Rabbit Targa- it really happened). Sunroofs were rare for the European market, so that's even more interesting. 

It was originally Polaris Metalic (silver) with blue leather. At some point the car was painted white, along with it's factory alloy wheels. White wall tires were fitted to complete the interesting look. The car is very complete, with a fairly tidy interior. The power windows work with a little assistance. The car runs and drives. With no working clutch, the driving experience is even more exciting.

*Bringing Her Home*









With Trailer in tow I headed in her direction. I hadn't actually been able to see the car in person. I had to buy based on photos, more detailed photos, and answers to my many questions. Then I had to pay for the car, then come pick it up at a third party. Highly aware of the common scams, this was clearly not that. It was just a seller that did not or could not deal with the process of showing the car. Since the car was nearly half the price of others I were looking at and in far better overall condition I did take that chance. When I pulled up I was greeted with a clean California Title, a bill of sale, an original BMW key and a car that looked better than the photos I had been reviewing. 

Getting her on the trailer was fun without a clutch or a winch. We tried disconnecting the coil and driving up the trailer ramps with the starter, but that wasn't enough power to make the climb. So I had to drive it up and try to remember to turn off the engine once on the trailer. Things were going swimmingly until the car jerked to a stop with a loud crash! The exhaust (which was attached to the car only at the manifold and the tailpipe) was hanging just a bit too low. We thought it would clear, but just enough of it caught the hard edge of the trailer that it ripped the entire system right at the manifold. We gathered the parts and put them in the truck then gave it another run. This time she sounded like a terrific track runner. I drove it to the top of the trailer so easily that of course I forgot to turn off the motor until I just about drove off the front of the trailer. But I found the key just in time and avoided any more excitement for the day.

*In the Shop*

Back at the shop we pulled her down and settled her in. We will likely weld the exhaust back to the car so that we can drive her around a bit and have some fun before she's completely disassembled. We also want to weigh the 4 corners of the car with the exhaust in place so that we can design the weight balance of the new system with this in mind.

With the couple snuggled in for the night, I leave you with this little video of how great she sounds with no exhaust. 






Sorry, I don't think the YouTube function worked too well for me.

Until next time,

Paul


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## Boxster-warp (Jun 22, 2014)

Hello
The BMW is a Wonderfull Car, Respect.
Greetings Boxster-warp


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## jetdexter (May 30, 2018)

Today we finally took some tools to the CS. Before we tear it down, we thought we would repair the exhaust and service/adjust the clutch just so that we could run the car some. We will be selling off the entire drive train and wanted to shoot a driving video - running through the gears around town. Once we got the car up and took a deeper look, it was clear that a quick repair wasn’t going to happen. One of the downpipes bends had been pulled out of shape enough that it no longer lined up on each end. The other downpipe had taken a portion of the rear manifold with it. While it is all repairable, we decided that it was too “exhaustive” and time consuming. Any time spent here is going backwards from our actual goal, so we decided to move forward.










Weighing the CS

We want to weigh the four corners of the car so that we have a good basis for our new weight distribution. Our electric motor, batteries, and associated systems will replace an engine, a tranny, drive shaft, differential fuel tank, etc. The weight of our new systems can be equal to the items we remove , depending on the number of batteries we end up using. The minimum number of batteries to achieve the voltage and minimal driving range will weigh a tad less than our current drive train, but additional batteries to increase that range will add to the weight. We are somewhat flexible here, as we are not requiring a 300 mile-range car. We also don’t want to settle for 50 miles. Thus we need to weigh the car now, then weigh it again with it’s drive train removed. We can then begin that engineering. The good news here is that the CS is a fairly light car, weighing around 3100 lbs. It’s current successor can weigh 4500 lbs. Naturally our chassis and suspension is not built to handle that kind of weight, but we certainly do have a bit of room to play with and maintain a fairly light car. 










To be economical, we built a pair of scales using some basic parts. Our scales are capable of measuring 600 lbs, so we configured them to measure half-weight. We verified our rig’s half-measurement by weighting an item directly, and then using the scale. Once satisfied, We rolled the front wheels onto the pair, keeping the rear wheels elevated the same amount as our scales. We swapped the scales around a couple of times to verify that the readings were coming back the same. I assume that our final measurements will be off by a very small amount, but certainly within just a few pounds at each wheel which is certainly close enough for our needs. 

With a full tank of gas our CS weighs in at:

Front: 1743 lbs. (Drivers 916 lbs, Passenger 827 lbs.)
Rear: 1427 lbs. (Drivers 719 lbs, Passenger 708 lbs.)
Total: 3170 lbs.

Hood Upright Repair

The drivers side hood upright arm had been poorly repaired at least a couple of times and had failed again. We will likely move to a more modern and lightweight approach of gas-charged struts, but for the time-being we figured we should properly fix the stock setup. The sledgehammer that we had been using to prop the hood up has far more important jobs to do.










So that’s it for today. We hope to get in there again next week and have a drivetrain removal party. 

Cheers,

Paul


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## jetdexter (May 30, 2018)

*1974 BMW CSE Progress*

*Setting Up Shop*

https://bmwcse.com/buildblog/2018/10/12/setting-up-shop

Last week was mostly spent setting up the shop. My A/V company has some extra warehouse space so after moving various pallets of amps, speakers, theatrical lighting, we found a nice corner for the project. 










We aren’t swimming in money, but we do like the safety and efficiency of a hydraulic lift. It made sense with the amount of fabricating that needs to be done top and bottom, in addition to the typical restoration work.

To save $400 in freight, I opted to pick it up in Los Angeles. Using my short-bed Tundra only half of it hung past the tailgate so wheelies were enjoyed in rush hour traffic on the 405.










Once the lift was setup, we finally got to get a good look under the car. We found various rust repairs that appear to have been performed in decade intervals. I was surprised not to see any duct tape.

This is going to be more fun than we thought!
Finally, we printed out and posted a reminder of the goal on the wall. When we find ourselves elbow-deep in rust, welders, batteries and wires we may risk losing sight of the dream. I assume that a poster will be all it takes to get us back on track 










Until next time,

Paul


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## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

Out with the Old

This week we saw our first real milestone: Removing the 3.0 straight-six motor and drive train. It was bittersweet to be sure. It is not lost on me that this (and every) BMW straight six is a beautiful piece of engineering. I have had a number of people remind me that I am ruining a classic combination of coach and motor by converting her to electric. 








On that note, last weekend I rode along with a friend on a two-day rally through the Southern California mountains and deserts. In the group were some of my favorite gas-burning vintage cars: Porsche’s, BMWs, Austin Healeys, Triumphs and more. We drove my buddy’s terrific vintage Alfa Sport Sedan. These great cars offer their drivers the enjoyable chore of working the clutches, gears and non-electric steering through the curves and the grades. The feeling returned from this enthusiastic driving is pure joy.

I wanted so badly to take the coupe on this drive before it’s disassembly and restoration, but neither exhaust nor clutch it was pretty much out. All weekend long I kept thinking about what I was giving up by removing the soul of the vintage machinery for the advantages of the electric. But the CSE is to be my daily car. A weekend of smelling like exhaust, fuel and coolant is awesome with a bunch of car guys, but not ideal for a board meeting or date night. I am trying to build something that can give me a slice of the vintage soul in a “scent free” edition, so that I can enjoy it every day.
Out with the Old








Before we strip the car all the way down for it’s proper restoration, we wanted to find out just how much the drive train weighs. The engine, transmission, drive shaft, differential and cooling system weigh far more than our little electric drive unit. But the tank of gas weighs a fraction of our new fuel: Batteries. In order to achieve our goal of 250 miles of range we need quite a few of those heavy beasts. A few posts back we weighed in the coupe in at 3170 lbs. We are hoping that the drive train is a large amount of that weight. 








Things got off swimmingly. We started at the rear with fuel tank and the differential. We thought the diff would be maybe 40 pounds or so. We were happy to discover it a beastly 85 lbs! We were off to a good start. We left the half-shafts going to the rear wheels in place as those (or replacements) will connect to the Tesla drive unit. We then removed the drive shaft and the shifter. Finally we unbolted the transmission and motor mounts and lowered the car. We then removed the radiator and anything else involved in making the car go. Everything else stays in for the moment. We drained and properly collected gallons of various liquids, but somehow still had to mop up gallons more. A pesky tie rod that was interfering was just not interested in coming loose. Perhaps we could have pressed her apart, but it was more fun to whip out the grinder. At least we used safety glasses. 

After a few careful hours and one forklift, the motor and tranny were safely out of the car and on a pallet for it’s future owner. 
What’s the Verdict?








With no drive train our coupe weighs in at:

Front: 1020 lbs. (Drivers 576 lbs, Passenger 444 lbs.)
Rear: 1140 lbs. (Drivers 588 lbs, Passenger 552 lbs.)
Total: 2160 lbs. 

Drive train approximate weight: 1010 lbs.

In rough numbers, our Tesla drive unit weighs 295 lbs, and the battery modules weigh 55 lbs each for a minimum of 550 lbs. This brings us to 855 lbs. Add to that the weight of our fabricated mounts, battery enclosures, battery management and charging systems, and it appears that we should be able to end up about the original weight of the coupe. If needed, we still have the option of lighting up other portions of the car such as seats, carbon-fiber hood and more. We are exploring some suspension options that could be lighter and more friendly as well.

Until next time,

Paul


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## brian_ (Feb 7, 2017)

*Re: 1974 BMW CSE*



jetdexter said:


> With no drive train our coupe weighs in at:
> 
> Front: 1020 lbs. (Drivers 576 lbs, Passenger 444 lbs.)
> Rear: 1140 lbs. (Drivers 588 lbs, Passenger 552 lbs.)
> ...


I was surprised that the total for the powertrain came out that high, but inline-sizes are heavy and this is old tech. The large bias to the driver's side is strange - the steering column and pedal cluster shouldn't make that much difference. The diagonal values suggest that the car is not straight, or the springs are unequally sagged... and neither is surprising at this age.



jetdexter said:


> In rough numbers, our Tesla drive unit weighs 295 lbs, and the battery modules weigh 55 lbs each for a minimum of 550 lbs. This brings us to 855 lbs. Add to that the weight of our fabricated mounts, battery enclosures, battery management and charging systems, and it appears that we should be able to end up about the original weight of the coupe. If needed, we still have the option of lighting up other portions of the car such as seats, carbon-fiber hood and more. We are exploring some suspension options that could be lighter and more friendly as well.


Carrying only two-thirds of the Tesla battery does keep that part of the weight down, which is okay if you can live with the shorter range and lower motor power.

I doubt that all of those other bits can be done in 155 pounds, but it might be close. Remember to add a cooling system to your list. The structural changes to mount and drive unit and the body changes to accommodate it will also add weight.

It's very unlikely that you could save any meaningful amount of weight (relative to the total for the vehicle) by changing suspension components, at least at any reasonable cost.


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## jetdexter (May 30, 2018)

I very much appreciate your thoughts- so I won't defend myself, but I do have a few thoughts- and I wonder what you think back...

Yes I was happily surprised at the weight. While my scales aren't completely accurate, they are accurate to themselves, and since my first weight was very close to what BMW says the car weights, I know that I am extremely close. 

Regarding the LR difference, that inline did lean way into the passenger side, so it makes sense for the amount of difference there- though more than I expected. And with a full tank of gas removed from behind the rear passenger tire (and the spare tire still in) the rear balance made sense to me. I may ditch the spare, but wanted to leave it in for this purpose. 

Regarding my 10 module minimum. It is enough to build up the voltage, but true, not nearly the range. Still, the Model S is 4800LBS, and my car 3170. That is fairly significant to the performance and range I should expect. I do hope to get 12 modules in there, but I think my weight to performance ratio will top out about there. 16 modules in a 4800LB car that gives 300 mile range versus 10-12 modules for 3200 pounds and I should beat my 250 mile goal. I had the 70D with 240 miles and I was very happy for everything around So-Cal. 

I wonder your thoughts...


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## Duncan (Dec 8, 2008)

Hi Jet

I would expect to need MORE power at highway speeds in your BMW - weight is not as important as aerodynamics!

Teslas get 300 miles out of 100 kwh - 3 miles/kwh - my 800 kg Device gets about 28 miles out of 14 kwh - 2 miles/kwh

Your BMW will be a lot better than my Device - but I suspect 10 modules will only give you about 180 miles


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## brian_ (Feb 7, 2017)

jetdexter said:


> Yes I was happily surprised at the weight. While my scales aren't completely accurate, they are accurate to themselves, and since my first weight was very close to what BMW says the car weights, I know that I am extremely close.


I'm not questioning the validity of the measurements - was just surprised by some of the weight information. 



jetdexter said:


> Regarding the LR difference, that inline did lean way into the passenger side, so it makes sense for the amount of difference there- though more than I expected. And with a full tank of gas removed from behind the rear passenger tire (and the spare tire still in) the rear balance made sense to me. I may ditch the spare, but wanted to leave it in for this purpose.


The engine inclination and fuel tank location would explain a right-side-heavy car, which isn't so bad because it counterbalances a solo driver's weight. They don't explain why the car with no engine or fuel tank and no driver is so left-side-heavy. The spare tire doesn't weigh much compared to the side-to-side bias.

The left-heavy distribution may not be a big deal, and the cause probably doesn't matter, but I think it's worth considering some placement of components toward the right side.



jetdexter said:


> Regarding my 10 module minimum. It is enough to build up the voltage, but true, not nearly the range.


10 modules isn't just 10/16ths of a 16-module Tesla's capacity, it's also 10/16ths of the voltage. You can get Tesla Model S/X modules rewired to 12S (instead of 6S), but if you do that you can only use up to eight of them. Available voltage limits available power at higher speeds; that might not matter to you.



jetdexter said:


> Still, the Model S is 4800LBS, and my car 3170. That is fairly significant to the performance and range I should expect. I do hope to get 12 modules in there, but I think my weight to performance ratio will top out about there. 16 modules in a 4800LB car that gives 300 mile range versus 10-12 modules for 3200 pounds and I should beat my 250 mile goal. I had the 70D with 240 miles and I was very happy for everything around So-Cal.


I understand the logic, but the expectations for range may be high. The Model S is much heavier than the CS, but consumption doesn't just depend on mass. The Model S is also larger, but likely has a much lower coefficient of aerodynamic drag than the CS (which was okay by the standards of the 1960's and early 1970's). Especially at higher speeds, the aero will probably be more important than the weight. Even if the range is only 200 miles, that would be long for a DIY conversion and presumably would be fine for this vehicle.


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## jetdexter (May 30, 2018)

Thanks guys- 

I think that we may have landed on a couple of points - Even the Tesla gets less range at freeways speeds. I could never get 240 miles on road trips in my Tesla, but I would easily get that around town. So when I say I am hoping for 250 miles it is mostly certainly around town. Without the Superchargers I used for road trips, this car will certainly not be used for long hauls. Besides, living in L.A. we are lucky to get up to 30MPH on the freeways. So I don't think my 70's aerodynamics are going to hurt me. So with my 10-12 modules I might be pretty optimistic, but not crazy I don't think.

Great points on all the rest. That is why I am here- to keep learning from you all.


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## Duncan (Dec 8, 2008)

Good points - I get twice the distance at "town speeds"


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## brian_ (Feb 7, 2017)

brian_ said:


> The diagonal values suggest that the car is not straight, or the springs are unequally sagged... and neither is surprising at this age.


A little more detail on this issue...



jetdexter said:


> With a full tank of gas our CS weighs in at:
> 
> Front: 1743 lbs. (Drivers 916 lbs, Passenger 827 lbs.)
> Rear: 1427 lbs. (Drivers 719 lbs, Passenger 708 lbs.)
> Total: 3170 lbs.


The diagonal totals should be the same for a properly set up normal car (not a drag racer or an oval track racer). In this case:

left front + right rear = 1624 lb
right front + left rear = 1546 lb
That's only 78 pounds difference (2.5% of the total), probably no problem at all.



jetdexter said:


> With no drive train our coupe weighs in at:
> 
> Front: 1020 lbs. (Drivers 576 lbs, Passenger 444 lbs.)
> Rear: 1140 lbs. (Drivers 588 lbs, Passenger 552 lbs.)
> Total: 2160 lbs.


In this case:

left front + right rear = 1128 lb
right front + left rear = 1032 lb
That's 96 pounds difference, and 4.4% of the total. The car appears to have been set up to handle the offset engine, and will likely need some tweaking after half a ton or more of EV components are added (in different positions from the original powertrain).

It's a relatively small detail, and I'm sure that most builders wouldn't worry about it, but since you have the individual corner weights and are building a car known for handling, it would be a good detail to sort out... eventually.


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## jetdexter (May 30, 2018)

brian_ said:


> A little more detail on this issue...
> 
> That's 96 pounds difference, and 4.4% of the total. The car appears to have been set up to handle the offset engine, and will likely need some tweaking after half a ton or more of EV components are added (in different positions from the original powertrain).
> 
> It's a relatively small detail, and I'm sure that most builders wouldn't worry about it, but since you have the individual corner weights and are building a car known for handling, it would be a good detail to sort out... eventually.


Brian- thanks for that, I appreciate your details here. My post is from my blog site (which has to appeal to all types of folks- some that just want to follow the project for fun) I didn't get too into the WHY I was weighing the corners. It was certainly to find out exactly where I can be putting in these components. We are literally making bricks of battery modules the same size and weight so that we can insert them and weigh the car with various scenarios.

While this is to be a normal car- not a track car- I do want it to behave extremely well for spirited driving as a car enthusiast. 

So I very much welcome your thoughts on this- I am excited to fit in the components in such a way to better the original weight distribution if possible. I will be trying under the rear seats as well as a bit out back- but using the engine compartment for a majority.


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## brian_ (Feb 7, 2017)

jetdexter said:


> ... I am excited to fit in the components in such a way to better the original weight distribution if possible. I will be trying under the rear seats as well as a bit out back- but using the engine compartment for a majority.


The car was moderately front-heavy (55%) when stock, partially due to the engine being too far forward; that wasn't bad for the time, is still normal for a non-high-performance car, and shifts rearward with passenger and cargo load (so you don't really want 50%/50% when complete and unloaded).

Without a powertrain, the roller is at only 47% front weight bias (because the boat anchor engine was up front), which is too rearward... but it will shift forward as those battery modules are stacked in the front, because that's best and almost only place to put most of them.

Under the rear seat would be nice, but since the fuel tank wasn't there (unlike a modern vehicle), and the suspension extends under the seat, there isn't a good place to receive big rigid boxes. I would be tempted to replace the rear seat with a substantial battery box under a parcel shelf, since I wouldn't expect to have rear-seat passengers.

The fuel tank and spare tire location is right at the rear, and not great for handling dynamics.

It's going to be an interesting packaging challenge. 

There are some good drawings for layout planning online, such as those on this website:
BMW E9 CS group 2 (1970)

Another E9 project illustrates what you find when you strip the body down to just the shell, including a not-so-useful space under the rear seat (see the last photo):
BMW E9 – chassis restoration


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## brian_ (Feb 7, 2017)

A little more on the space in the rear...

The E9 seems to have the space under the trunk divided down the middle, with the spare tire well on the left and the fuel tank on the right. See the third-from-last image in the restoration link above for illustration. Whatever is left of that space after the Tesla drive unit could be used, but staying to the front of that space would certainly be preferable.

The spare tire well would need to be cut out and replaced with something better shaped for the battery modules. The fuel tank side is just a hole, so a battery box is required to protect the modules from the outside world, to protect the modules from stuff in the trunk on the inside, and to protect interior contents from the effects of severe battery failure. The interior side protection is needed on the spare side, too.

The structural divider between the spare and tank could probably go, but it's worth considering how to effectively replace it, for rear impact strength if nothing else.

The drive unit mass is substantial, and it is centred behind the axle, so you may not want any battery behind it all to avoid to front-heavy mass distribution. It's worth some specific planning and calculation to see what configuration will work.

There is another rear location which could be used for battery modules: the front of the trunk, on that shelf over the axle. It's high (which is bad), but further forward and a usable size and shape. If using that and not the fuel tank space, the fuel tank space could be made into a covered storage cubby to make the remaining trunk more usable.


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## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

_Here's another update from the blog. Nothing EV specific yet, but getting closer_

November was an extremely busy month outside of this project. We only were able to fit in a few half-day sessions on the car, but that was enough time to get her stripped down and sent off to be blasted. 

*The Hanz and Franz Effect*










Since Karmann had coach-built these cars for BMW, we discovered some very interesting peculiarities as we were disassembling. At the risk of sounding insensitive (but with a tribute to Saturday Night Live) we dubbed this the “Hanz and Frans” approach to building cars. 

The best we can tell, Hanz was responsible for the driver’s side, while Frans assembled the passenger side. Where Hanz would use a 5mm phillips screw to attach a bracket, Frans would use a 6mm hex bolt to attach the same bracket on his side. One might argue that this was not the case - instead attributing it to 44 years of repair work done by various people. Probably so. We prefer to imagine Hanz and Frans starting the day with a good strength workout, putting down plenty of sausage, then getting to work assembling the car each using whatever bin of fasteners they had handy.










*The Quality and Design*

On the other hand, it was equally fascinating to discover some wonderful engineering and design. The dash for example. While it appears to be robust component, it is instead a series of small layered assemblies. The steel of the dash frame forms the entirety of the shape. Wonderfully high grade plywood forms the dash trim pieces themselves, and 44 years later, they are still in terrific condition. 

We bagged, tagged, binned, and categorized every part on the car. So many trim pieces are in terrific shape and can go right back on, while so many more will be cleaned, straightened, polished, painted, wrapped, powdered, or chromed.










We had great fun cutting away every bit of wiring in the car. One buddy that dropped by left in horror wondering how we were planning to recreate the wiring harness. We could hear him yelling as he drove off “So long suckas- have fun putting that back together!” 

We wanted to start fresh with the wiring for a few reasons: First, none of the wiring that had to do with the gas motor will apply. Second, we want to modernize how the lights and windows are powered. No longer does every light, motor and switch require several wires running to it. We will be running LEDS for nearly every light, so fewer, smaller gauge wires can be ran to just about everything. Finally, we need to account for the 12v side of the EV systems. For the combination of these reasons, we want to design an entirely new wiring schematic. The goal is that it will look like we bought and installed a modern factory wiring harness.

*Off to the Blaster*










Finally, she was ready to head to the blasting shop. We agonized about removing the suspension and fabricating a dolly for her, but in the end we opted to send her off on her own tires. We will remove the suspension when she returns and finish grinding and sanding those last sections ourselves before we begin the metalwork. 

We can’t wait to see her return as bare metal. We have new floors and frame rails ready to weld in along with a number of other areas which we will better evaluate when the paint is off.

Until next time!

Paul


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## jetdexter (May 30, 2018)

brian_ said:


> A little more on the space in the rear...
> 
> The E9 seems to have the space under the trunk divided down the middle, with the spare tire well on the left and the fuel tank on the right. See the third-from-last image in the restoration link above for illustration..


Hi Brian,
Thanks for all that. Yeah, as we were stripping her down we began to so some basic imagining of these locations. It seems certain that we should be able to get a couple of modules under the rear seats. We do figure to stack 2-3 rows high in the front engine compartment, but want to leave enough space for an A/C unit and other items. We removed the large vacuum unit for the brakes and will provide electric power for that to free up more space. 

Perhaps when the car comes back clean I might take a batch of photos at even angles and draw in to scale some of these ideas. Love to hear what you and the others have to say based on those. Clearly you might have reasons why some of my ideas wouldn't work, and that is exactly what I am looking for with this group!

Thanks again!

Paul


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## brian_ (Feb 7, 2017)

jetdexter said:


> Perhaps when the car comes back clean I might take a batch of photos at even angles and draw in to scale some of these ideas.


I'm looking forward to those.


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## Emyr (Oct 27, 2016)

Depending on your motor weight, you might get a better weight distribution by locating the spare wheel under the bonnet/hood, and using both halves of the under-trunk space for batteries. You'll definitely shift the CoG downwards.


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## brian_ (Feb 7, 2017)

Emyr said:


> Depending on your motor weight, you might get a better weight distribution by locating the spare wheel under the bonnet/hood, and using both halves of the under-trunk space for batteries. You'll definitely shift the CoG downwards.


An interesting idea. It would also shift the CofG rearward... maybe too much? I think it would make sense to calculate the new CofG - at least front-to-back and ideally vertically as well - before committing to component locations.


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## Duncan (Dec 8, 2008)

With modern tyres and a modicum of care I would simply eliminate the spare wheel
Take one of those aerosol tubes of tyre gunk instead


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## Moltenmetal (Mar 20, 2014)

I did as Duncan suggests- a tube of that slime stuff for puncture repairs and a small 12V compressor takes up a lot less precious trunk space than a spare tire and rim.


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## jetdexter (May 30, 2018)

Happy New Year folks! Here's another blog post update from bmwcse.com:

Swiss Cheese and the Rebar Method









Last week the coupe arrived back from the glass blaster. We knew that we were going to discover hidden issues, so we weren’t surprised to find quite a few areas with poor metal work and plenty of filler covering things up. The car had been repainted 10 or so years ago, and one can hide a lot of sins under a fresh coat of paint. 

Now that all is exposed, we have plenty of Swiss Cheese holes. Behind the sunroof (where the water drains had clogged decades ago). On fenders, behind rear wheels, doors and more. 









------------------------------------------------------------------------------------------------
The Rebar Method










What we were not prepared to see was rebar. Inside the driver’s front wheel well was plenty of fiberglass, reinforced with rebar and more fiberglass. Scott, our faithful blaster said that in his years of blasting restorations he has never discovered rebar as a structural component. I never thought that Home Depot would have many parts for auto restoration.

As bad as this is, we already knew of a lot of repairs in the strut supports, so we won’t let this beat us down too much. We will source new metal and get it cleaned up properly. It’s too early to get beat down yet.
------------------------------------------------------------------------------------------------
Battery Module Placement











Now that things are finally clean and free of grease, we took an opportunity to dry-fit some foam models of our Tesla battery modules. Through our research we know that we can run these units vertically with very little gap between them - as little as 3/16” if we configure mounting rails just so and our wiring setup doesn’t push the bolts to the next module. In this photo, we have 9 units across the engine bay (but we may need to reduce this to 8 to allow a bit more room for reality). The far left and right unit are sitting on frame rails, but the center units are extremely low in the bay. 

We then add 2 more where the radiator sat, and finally up to 4 more can stack flat on top of the main cluster of modules. This gets us 14+ all in the engine bay, and the bulk of the weight will be much lower than the engine weight which sat much higher in the compartment. 

To keep the center of gravity the lowest, we would prefer not to stack that last 3-4 modules on top of the base cluster. One module does fit under the rear seats with some modification to the tunnel. We would have to perform a lot of modification to get one or two where the transmission sat. Finally we could easily get 2 or more in the trunk, but we prefer to not add the weight back there, as the drive unit is as much weight as we like back there.

------------------------------------------------------------------------------------------------

Raspberry Pi for dessert









We picked up a Raspberry Pi with dual isolated CAN Buses and a 7” touchscreen to begin programming our control system. This system will control most of the basic functions of the car from blinking the turn signals, setting the interior to 70 degrees and more. It won’t perform critical motor and braking control, but it will push to the Tesla control unit what preset we are running (i.e. Standard, Sport or Valet modes) I will describe more of these details in a future post.

Well, that’s all there is to report this time around. Happy New Year!

Paul


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## [email protected] (Feb 1, 2019)

Excellent thread! I am definitely following this. I am new to the forums and learning as much as I can. I have a 1978 Mercedes C123 candidate for electrification


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## jetdexter (May 30, 2018)

_Here's another update from the Blog_

*Cut, Weld, Smooth, Repeat.*

After ordering up a truckload of sheet metal and a 50 gallon drum of perseverance, we dove head-first into rust repair. We started in the rear of the car going spot by spot through the simpler areas. Below are some photos of one spot of the trunk. We cut a section out, weld a fresh section in and smooth it out. Good as new, right? Well yes, after we do this process a hundred or so more times.








_Cut out the cancer…Weld in a fresh section…Then smooth it out._

*Then there are the floors*

While the bodywork is happening up top, we also began work on the floors. The passenger side sub-frame rail underneath was rusted through. We sourced a pair of new replacement rails, but they didn’t really match up to the angle and length at the front. After some debate about fabricating from scratch, we decided to modify these units which wound up working out well. A bit of smoothing will still take place after the floors go back in, and we will move to the driver’s side.








_Remember this photo from a few posts back? Looking a lot better now._

*Some toys showed up*

Our Tesla drive unit, controller, and battery modules have arrived. We have to hand it to HSR Motors/057 Technologies for terrific communication, education, support and packing (thought you wouldn’t know it from these pictures, as it looks a little like Christmas morning just happened). We chose 057 Technologies after a lot of consideration - and I know there are more opinions here than there are stars in the sky. We tossed around buying a totaled Tesla at auction, and stripping her ourselves of all her goods. We considered saving a few bucks and buying from any number of cut-rate dismantlers. Lastly, was the idea of buying from a shop that specializes in Tesla and EV conversion support. After visiting some, and chatting with others, I felt like I bought into not only the passion, but the engineering approach that 057 has taken with their controller, but also the drive units themselves. 









We will surely see if we made the right call once we can dive into this gear in the coming weeks. In the meantime, it is back to Cut, Weld, Smooth, Cut, Weld, Smooth, Cut, Weld Smooth…


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## jetdexter (May 30, 2018)

[email protected] said:


> Excellent thread! I am definitely following this. I am new to the forums and learning as much as I can. I have a 1978 Mercedes C123 candidate for electrification


Thanks Lush- Looking forward to seeing that project! Let me know if you start a project thread here.


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## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

Hi all,

_While this post isn't related to the EV portion of the build, I just want to continue to paste over the updates from the bmwcse.com build blog._

*Here Comes the Sunroof*

You might remember that one of my requirements for the coupe was that it have a sunroof. Of the 60 or so cars I have owned, a majority of them have been convertibles - I simply crave the open air. While this car was not going to be a convertible, it was most certainly going to have a sunroof.










But our story takes a turn with the little tube shown in this photo. The photo shows a new tube, but imagine one just like it that was plugged inside like a clogged drain. This tube, along with 3 comrades, takes the portion of rain water that makes its way through the sunroof seal, and passes it into hoses that run to the bottom of the car. This is a great plan so long as the tubes aren’t clogged, and in our case, the tubes had become very clogged, very long ago. Water would come in and take up permanent residence - turning our roof and the sunroof frame mechanism to rust. 

We were unaware of this rust until the car came back from the media blaster. We were then faced with three options: 1, we simply fill in the roof. This is the course that any sane person might take. But since a sunroof was an early requirement, this was not an option. 2, we could fill it in, then install a very nice modern OEM electric sunroof. Our car is a “resto mod” after all, so a blend of modern elements is not out of the question. However, another goal is to retain the classic styling of the car, and the original steel sunroof is an important part of that. So our 3rd option was to painstakingly rebuild the roof and frame. This took a few good weeks to do, and here is the story:









Here is the roof from inside the car. Rust on all four sides.









The damage to the frame (the sunroof track) was even worse than the roof itself.

*Let’s make a new roof:*









Trace the sunroof hole and prep it for cutting.









Cut along the line- this part seems a lot like elementary school art class but with steel.









Begin the process of bending the edges to form our thick and smooth final edge.









Continue the bending and shaping process with the panel setting on the car.









Finally we have a panel which is looking like a final product.









Weld the piece in, then smoothing, smoothing, smoothing.










We also found that we had to strengthen the sagging steel behind the sunroof as well. We then smoothed and smoothed and smoothed some more.

In the end we now have an entire roof that is better than new.

Continued...


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## jetdexter (May 30, 2018)

...Continued due to the limit of 10 photos- all of which I have hosted elsewhere 🤨

*Repairing the Sunroof Frame*

The jig is up. Well, in the photo the jig is on the bottom and the frame is up, but you get the idea.









Our frame attached to the jig.









With the frame on the jig we can cut out sections and start replacing them.









Tyler is a patient craftsman. Give him some steel and some tools and he can turn out just about anything.









Here’s a fun, rusty rounded corner,









And here’s the new replacement piece all clean and tidy.









All the new sections welded and smoothed into the frame.









The restored frame receives a fresh black coating.









Installing the frame back into the coupe. Tyler loves crawling around grinding things in the car.









It’s looking good from up above.

Finally we set the sunroof back in and check the fit. The gaps are cleaner than when we bought the car. With our new drain tubes and fresh hoses, as well as a new seal in place we should be good for another 45 years of open air, rust-free enjoyment.









While all this sunroof work was going on, there was _a lot of junk going on in the trunk._ Next week I’ll post an update on all that.

Cheers!

Paul


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## jetdexter (May 30, 2018)

_Here is another post from my bmwcse.com Blog_

While all of that sunroof work was being done Brett and I started to have some fun with the Tesla drive unit. 










We are not the first people to retrofit a Tesla unit into another car. We leveraged some of the engineering, trial/errors and successes from some of the more graceful projects that we have followed.

We started by clearing out the trunk floor. We want the motor to sit no lower than the original differential, but also no higher than necessary - leaving us with a good amount of trunk space. 

*Getting off the Ground*

Our Tesla unit weighs 291 pounds, so I can’t exactly hold it in place while Brett bolts it to the car. We welded up a rolling stand that could safely hold the unit under the car, then we would use the car lift to lower the coupe to the unit. 








Here’s our Tesla motor stand. I am going to reach out to Elon to see if he wants to put an order in for several









A forklift is the closest thing we have to an engine hoist, so here we go.









The unit feels secure in its temporary home.


*Reinforce and Fabricate*

With the unit on the rolling stand we put it into position to verify our mounting design and overall clearances. We strapped the rear wheel into a relative ride height, so that we could check the axle angles.

While we had done our homework I am not going to lie - there was some relief when everything fit without obstructions.









Tesla Unit in Position


Regarding the mounts: There is a front mount which was a simple matter. The side mount can be tricky since there is suspension right there, and the rear mount has nothing to hang from. 









We plated the front and rear of the wheel well to distribute the loads and to give us something to attach to.









Brett welds in the horizontal plating, which will support our front mount.

_continued below..._


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## jetdexter (May 30, 2018)

*The Front Mount*

(Sorry I don't know if I figured out how to present YouTube videos)




Cutting the thick stuff is like cutting warm butter when you have a plasma torch.









The front mount had the trickiest shape to it and required some bending of the center plate.









The front mount welded into the car.

*The Side Mount*









We created a side mount plate with a compound bend by notching, then smoothing out.









Welding the side mount sections to our plate.

*The Rear Mount*









The rear mount suspends from a beam which spans between the wheel wells.









Reinforcing the hanging points with gussets. It was just an opportunity to take a photo through the taillight hole.

*Clean Things up and Hang the Unit*









With the welding done, we cleaned up any rough edges and applied etching primer to everything.









Finally the drive unit is hanging in it’s final home! We strapped the front of the car down to the lift just in case things got a little back-heavy





The moment of truth when the Tesla unit is successfully raised off its stand.









The placement leaves plenty of usable trunk space. We have a large and deep rear section, then an upper forward shelf (with perhaps a plexiglass floor for any Cars & Coffee events we may find ourselves at).

Next we connect the axles from the drive unit to the hubs. So that we don’t twist the old BMW axles we opted for Tesla performance axles, which will mate (somehow) to the BMW hubs.

That’s it for now- until next time!

Paul


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## brian_ (Feb 7, 2017)

jetdexter said:


> We started by clearing out the trunk floor...


It looks like a lot more than the trunk floor went. 

In the middle, at the front of where the original final drive (differential) housing would have been, there appears to be a bracket which was likely bolted to the nose of final drive, and likely goes forward to a beam that the suspension arms mount to. In later photos, it looks like that bracket was cut off of the beam. The back of the final drive would have been supported by a mount. If that's how it was done, the beam and the final drive with its brackets formed a T-shaped subframe for the suspension, and the rear leg of that is now gone. With only two mounting points of the remainder of the subframe (the beam) to the car, the subframe is no longer properly supported and will twist under loads.

Ideally, the structural role of the bracket, final drive housing, and final drive rear mount, would be replaced by a tube arching over the drive unit to the new rear mounting point.

Maybe my guess about the structure is mistaken - maybe BMW decided to make one model different from all of the others - but do you have a photo of the suspension arms and what they are mounted to?

Until you're sure this is structurally right, I would encourage you not to support the car on the rear suspension, and certainly not to drive it.

The attached images:

image of cut out trunk floor, showing the bracket
later image, showing the subframe cross beam and where the bracket was probably cut off of it
suspension and subframe from a BMW 2002 (not a CSE), but is shows what the corresponding parts of the CSE likely looked like:
(somebody else's image from Photobucket, plus annotations)


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## brian_ (Feb 7, 2017)

jetdexter said:


> We have a large and deep rear section, then an upper forward shelf (with perhaps a plexiglass floor for any Cars & Coffee events we may find ourselves at).


I like that! Maybe place for a bolted-in panel, with steel (or aluminum) and acrylic (or polycarbonate) panels for driving and showing?


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## jetdexter (May 30, 2018)

Brian,

Thanks for the thoughts. You are correct that we did cut off the bracket that held the front of the Diff, and the rear of the Diff did connect to the car forming the tee you mention. We do plan to reconnect this tee structure in some form.

It is a bit of a strange setup, as the point of isolating this front unit (in my estimation) was purely to isolate the differential vibrations from the car. Front drive cars often simply attach the trailing arms to the car itself. So we are doing a bit of research to determine the best course modifying this. Either we reverse the tee shape forward and connect it with a mount (with bushing) in the tranny tunnel, or we simply shorten the tee and attach closer to the Tesla front mount. 

Thanks again for your thoughts and concern - it's what I love about this group!

Paul


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## Duncan (Dec 8, 2008)

Hi Paul

Don't forget that the Tesla unit will see wheel torque not motor torque 

The further apart (fore/aft) that the mountings are the lower the loads that your mountings will see


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## brian_ (Feb 7, 2017)

jetdexter said:


> You are correct that we did cut off the bracket that held the front of the Diff, and the rear of the Diff did connect to the car forming the tee you mention. We do plan to reconnect this tee structure in some form.


Good 



jetdexter said:


> It is a bit of a strange setup, as the point of isolating this front unit (in my estimation) was purely to isolate the differential vibrations from the car. Front drive cars often simply attach the trailing arms to the car itself.


The T-shaped subframe has the same purpose as any other rubber-mounted subframe: to isolate the components on it from the vehicle structure. Yes, lots of vehicles do not use a subframe like this... they mount powertrain and suspension components directly to the structure at either at the front, or the rear, or both. Both differential gear noise/harshness and road noise/harshness through the suspension are handled by the rear subframe in this case; that's typical for rear-wheel-drive vehicles with an independent rear suspension, but not a universal practice.



jetdexter said:


> So we are doing a bit of research to determine the best course modifying this. Either we reverse the tee shape forward and connect it with a mount (with bushing) in the tranny tunnel, or we simply shorten the tee and attach closer to the Tesla front mount.


Logically the Tesla drive unit would be mounted to the rear subframe; that's what Tesla does (both front and rear), and what probably every other current production EV has at the driven axle(s). Ideally, perhaps the existing CSE subframe could have been extended to two new rear mounting points to the unibody (replacing the differential case mount), and the Tesla drive unit could have been mounted to it instead of directly to the body. The Tesla front mount would be bracketed off of where the diff bracket was, the Tesla side mounts would go to the subframe ahead of the new subframe mounts to the body, and the rear Tesla mount would go to a new crossmember of the subframe. But that isn't the only way to go and it's not what you have been building.

Assuming that you want to stay with the direct-to-body mounts that have already been built for the Tesla drive unit, all that remains is to restore a third mounting point for the subframe, which now handles only the suspension. To be effective, it must be significantly away from the axis formed by a line between the mounts on the crossmember beam; the diff mount was well behind that (and a long and awkward S-bend tube could go all the way back to your new crossmember), but a replacement could be significantly ahead as you described, or even above. Maybe back and up to your Tesla unit front mount would work. The point is primarily to keep the subframe from rotating around that axis between the remaining mounts.



jetdexter said:


> Thanks again for your thoughts and concern - it's what I love about this group!


Good.  Some people really only want to share what they have done, rather than have a discussion of possible designs.


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## brian_ (Feb 7, 2017)

Duncan said:


> Don't forget that the Tesla unit will see wheel torque not motor torque
> 
> The further apart (fore/aft) that the mountings are the lower the loads that your mountings will see


That brings up another reason for subframes: to spread loads further apart on the body structure.

In some case there is no isolation at the points where the subframe bolts to the body (it's just solid), which indicates that the subframe is being used to carry loads to suitable points in the body structure... or in some cases to allow a large assembly of components to placed into the vehicle on the assembly line in one operation (such as an entire engine, transaxle, half shafts, hubs with brakes, and suspension into the front of many vehicles... or the drive complete drive unit and suspension into the rear of a Tesla).

In this case, the stock Tesla mounting points (where the drive unit mounts to the subframe) are being used, and they're at the extreme front, back, and left side of the drive unit. During acceleration the front mount will push up on the body mount bracket, which looks quite substantial. Presumably that beam added for the rear mount can handle a similar downward force. The left mount (assuming there's no right-side mount) will basically just see a small share of the weight of the drive unit vertically because the motor is on the left side (plus all mounts take lateral force in corners and longitudinal force when accelerating and braking due to the mass of the drive unit).

Assuming 601 N⋅m (443 lb⋅ft) of motor torque, and 9.73:1 gear ratio, the axle or wheel torque could be 5800 N⋅m (4300 lb⋅ft), so if the front and rear mounts are about 60 cm (2 ft) apart, the difference in vertical force at those mounts could be 10 kN (2000 lb... one ton).


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## jetdexter (May 30, 2018)

Yes, we considered quite a bit the idea of attaching the front motor mount to the suspension subframe. In the end we saw a lot of well done cars where the drive unit was attached to the car directly- using the Tesla motor mounts as the isolation. Naturally them (and us) all created distribution for the loads of those mounts. 

To use the subframe for even one of them would mean not using the Tesla motor mount as it would require a multi-bolt setup (in the same manner as the 4 bolt setup to the differential- which was acting as a bridge to the rear mount to the car).

We decided on this route as the simplest and most robust. We did certainly plan for the 2000lb. We aren't auto engineers, but we do a lot of structural work where we have to account for 7x the maximum expected load for rigging. You can probably tell by the type of steel beam we used in the rear  It looks more like we are hanging speakers above an audience in a fine arts center... 

Regarding that subframe 3rd mount, I am doing a bit of research on just how much torque she will see. The 20" back or so that it attached in the past was because she experienced a lot of torque to spin the wheels. Now she does nothing but go along for the ride. The main thing is to lock her in so that the two main bolts aren't expected to do all the work- they would shear eventually. So I thought of going perhaps 12" or so forward in the tunnel and attach with a generic isolated motor mount, or even as you mention, straight up to our front Tesla mount (other than it being crowded up there).


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## mfox (Feb 3, 2013)

That's great , 
Maybe I missed out , but , how much modules will you put in ? , all 16? to get proper voltage..


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## brian_ (Feb 7, 2017)

jetdexter said:


> We decided on this route as the simplest and most robust. We did certainly plan for the 2000lb. We aren't auto engineers, but we do a lot of structural work where we have to account for 7x the maximum expected load for rigging. You can probably tell by the type of steel beam we used in the rear


Yes, the structural work looks good.  My comments were mostly for those other forum members who dismiss mounting these components are trivial, and don't understand the forces involved.



jetdexter said:


> Regarding that subframe 3rd mount, I am doing a bit of research on just how much torque she will see. The 20" back or so that it attached in the past was because she experienced a lot of torque to spin the wheels. Now she does nothing but go along for the ride. The main thing is to lock her in so that the two main bolts aren't expected to do all the work- they would shear eventually. So I thought of going perhaps 12" or so forward in the tunnel and attach with a generic isolated motor mount, or even as you mention, straight up to our front Tesla mount (other than it being crowded up there).


While torque reaction from the final drive housing would be the major torque about the lateral axis, that's not that's going on. The subframe takes all of the horizontal load of the suspension; while the suspension arm pivots and the subframe mounts are nearly in the same plane, that alignment isn't perfect so any cornering, accelerating, and decelerating forces will tend to twist the subframe around those two mounts. The third leg doesn't need to be anywhere near as long as it was (to the rear of the final drive), but something is needed, and it sounds like you're headed in a viable direction.


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## brian_ (Feb 7, 2017)

mfox said:


> Maybe I missed out , but , how much modules will you put in ? , all 16? to get proper voltage..


Just search this thread for "battery", and you'll get the evolving story of how many modules will be used. Yes, pack voltage is one concern.


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## jetdexter (May 30, 2018)

mfox said:


> That's great ,
> Maybe I missed out , but , how much modules will you put in ? , all 16? to get proper voltage..


We are starting with 14 modules, which is the old Model S 60 configuration. It will be very tight getting them in. We were able to get 14 foam models under the hood while accounting for just enough between them for connections and mounting. But it was still best-case, and our brake booster - while smaller than the original- will still eat up a bit of that space that we tested with. 

So we may wind up with 2 modules in the rear (above the drive unit where I wanted that cool plexiglass section to be). We could put one under the rear seats if we had to, but I don't want to have them spread out under every knock and cranny 

Bottom line is, 14 modules to get our minimum voltage, then if we do wind up better off than we think we will certainly add 2 more to bump up kWh.


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## mfox (Feb 3, 2013)

that's great , with 14 modules I think you'll get decent power, maybe same as tesla because it will be lighter.


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## jetdexter (May 30, 2018)

There has been a lot of progress on the car. Most of it restoration related, and I will spare you those details. Here is the progress on the EV conversion:

First, we wrapped up our work on the suspension subframe. As was discussed earlier in this thread the BMW uses the differential rear mount as a third point of attaching the subframe. My idea was to replicate this "T" by extending forward into the tranny tunnel. We fabricated an arm and used a Chevy motor mount up front. Here are a couple of photos (turned sideways since apparently that's how attachments show up in this forum if I don't bother to upload them elsewhere first).

We are using the 057 Tesla controller for the Tesla drive unit, which I have discussed some here. Jason has done a remarkable job with this unit. I know some here are dubious of 057, but I have had an incredible experience with his support. He has gone the extra mile for me in a number of ways.

He even shipped me a prototype of his forthcoming precharge unit along with a couple of Tesla contactors. This unit does an great job of automating the capacitor precharge sequence. 

We've been spinning the Tesla unit for a couple of weeks now, but we finally received our axles. We shipped a pair of Tesla inners to Lee at The Driveshaft shop who does amazing work machining and welding a flange to the inners. I also had them make a new pair of axles to handle the additional torque and horsepower. 

So things are moving along pretty nicely. 

I can't seem to be able to embed a YouTube video here any longer either- I just checked and the videos that worked great earlier in this thread no longer work. But here's a link if you care to watch! https://youtu.be/lShbH-DR42s

I don't mean to be a complainer, but this forum really does seem like it's running on 1996 tech


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## brian_ (Feb 7, 2017)

Nice work on the subframe extension. I don't think it matters for this purpose how the images are rotated.


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## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

I haven't posted here for quite a while. It's been a very busy year with work. We have taken the car a long long way since I last posted. While I have been pasting my blog posts here, I will save you all the storytelling of the blog, and just post the parts that might be of interest. I have loved the comments back from this group so I certainly welcome any additional thoughts as we get close to driving our car. I think it was last Spring when I last posted, so here is what we have done since then!

*Steering*

The original steering setup of the coupe, like the inline six motor is an important part of the E9 racing heritage. It was a conflict to rip it out, but for our particular goals, it needed to happen. We need to fit a lot of Tesla battery modules under the hood, and the large steering box takes up a lot of space. The steering column, box and all that iron linkage is also incredibly heavy. We opted to convert to a modern hydraulic power steering rack which is lightweight, efficient, and tucks in tight and low under the battery modules.

Why Not Electric Power Steering?

A lot of folks have asked me why we are not going with an electric power steering system. We deliberated a lot about this, as it is the future of power steering, and completely in line with our EV ethos. There are two reasons we opted against:

1- Electric racks have traditionally been terrible for driving experience in terms of their feel and input from the road. Only in very recent years have manufacturers made vast improvements in that area. The best systems also require constant communication with the computer which is receiving a lot of data about car speed, accelerometer, turn degree, steering wheel rotation and more in order to give proper assistance while retaining a desirable amount of road feedback. I went pretty far down this road before deciding that it was not going to be worth the effort - not when a good hydraulic steering rack feels great right out of the box.

2- We plan to use a hydro-boost brake system. Remember, we have no engine to produce vacuum. More importantly, vacuum systems are very large under the hood). Since hydro-boost systems run on a power steering pump, it made perfect sense to install a 12 volt power steering pump (from a Mini or Volvo) which will nicely power our brake and steering systems in a clean loop. 

I can see a time in the near future when there will be good options for electric steering and brake boost systems for conversions like this. Maybe my next car…

We started with a goal to use nothing but BMW or Tesla parts for this project. However, when it came to the steering rack we had to deviate. BMW’s modern racks are front-steer (the rack sits in front of the wheels) and our coupe is rear-steer. We prefer the car to follow the most widely-recognized standard of turn the steering wheel to the left and the car goes left. Since we did not want to completely modify our car to front-steer, we opted for another German-engineered rack from a car of similar weight and size. The Volkswagen MK3 GTI VR6 rack fit the bill. Even then we had to shorten the tie-rods quite a bit. It’s crazy how small BMW’s original “big coupe" is compared to modern "compact” cars.









We started by cutting away a handful of motor and steering mounts from our subframe. Cutting away stuff is usually my favorite part of the project. Brett here is having a dandy time with the plasma torch.









We test fitted our new rack in position using a series of construction clamps. They did the job just fine.









We cut some funny shaped sections of steel to make some mounts…









Then we got the rack tack welded in. Things look good in there. Nice and compact and low in the compartment. We will finish the welding and clean everything up after a bit more testing.

The “Everything You Touch” Motto*
*

A few months ago I was chatting with a friend about what should be original what should be modern on the car. Clearly our Tesla unit is modern, but that doesn’t affect how the car looks inside or out. He made a comment that stuck with me: “Everything you touch should be modern”. While I would love to take credit for the motto, we have really continued down that path. The steering column falls into that category.

We decided to fit a BMW E46 (1997-2006 3 Series) steering column for a few reasons. It weighs half of our original column, but it also gives us a host of features without going over the top with complexities (no electric memory tilt, etc) We get a modern turn signal lever with lane-change soft touch, a wiper lever with modern variable intermittent control. The computer button on the end of the turn signal lever can be useful to us as well. Most of all, we get telescoping and tilt steering. These items directly fall into our “Everything You Touch” motto.









Our E46 steering column is fitted into the dash with a bit of customization to the mounting areas.









Here’s our Frankenstein steering linkage. Starts as a BMW on top, then mates to VW linkage on bottom to connect to the steering rack.









A lot of cleanup yet to be done on the firewall, but the linkage is tidy and works wonderfully.

Finally, we have a working steering system that should feel great on the road, weighs about half of the original setup, and leaves more room for batteries. That there is a win-win-win.

I can't get the embedded YouTube function to work- if anyone has some advice I'd love to hear it! But here's a link to a video of the steering functioning:

https://youtu.be/ZnieRFItVc4

Cheers!

Paul


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## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

I've mentioned more than once that our car had not gotten along very well with snow and rain in the past. The more we dig into the structure, the more we think that she may have spent considerable time on the bottom of a lake.

Our coupe is no special case, mind you. Rust prevention was just not given much thought until later in the 1970s. I have talked to long-time owners who had to rebuild inner fenders, floors and rocker panels in the late 1980s - when their car was only 15 years old. Our car spent its first twenty years in Berlin where it saw plenty of weather, major rust is to be expected.

There are multiple layers of steel forming the coupe’s rockers. Since this was my first E9, we honestly didn’t know how many layers there should be, and the shape they should all take. Tyler performed a lot of archeological digging on each of the four corners to discover what the rockers should actually look like. We also received a lot of help and photos from the great community at e9coupe.com. We could have cut them entirely out and purchased/installed completely new rockers, but there was plenty of good and original metal behind all that rust worth preserving. We thought it more gratifying to leave the good and fabricate only the rotted sections of each layer.

Here’s a shot of our driver side rockers looking from the rear tire forward. It’s not a pretty sight. 










*We Can Rebuild It*









We began by carefully cutting the rot out layer by layer back to good steel. This photo shows what was left once the rot was removed.









Tyler then fabricated a section to rebuild the first layer.









We then started fabricating the next layers. We also rebuilt the lift point pockets.









More fabricating and more welding…

*Surely the front wasn’t as bad…*









The front was no better than the rear. Rust is one thing, but some driveway rust repair had been done at some point confusing how things should actually assemble. This required Tyler to do some real digging on both driver and passenger sides to recreate how the layers were supposed to look.









Figuring out what was supposed to be going on was the biggest challenge.









We are not against buying sections of metal when it makes sense. More than happy to not fabricate this complicated little guy.

*Capping it all off*

With the structural layers all complete we can finally cap it all off. We went our own direction here, opting for a custom cap with tight gaps to the fender and quarter panel which we welded in place. This provides a very clean and tidy look.










*Meanwhile, we were floored.*

While all this was going on we were also fixing up the floors. The coupe had Fred Flintstone floors on all four positions. We purchased new floors for this. The rears were perfectly stamped and shaped for the car, but the fronts seemed to be a generic “Automobile/Front” floor pans. The stamp was directly over the frame rail. So we cut off the side, pushing the stamp to it’s proper place between the rail and the rocker. We then extended the inside to the transmission tunnel and curved all the edges to mate to the car. A bit of work, but in the end it looks as good as the floors I saw BMW Classics doing in Munich last winter. 










Cheers!

Paul


----------



## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

*Just Spinning Our Wheels*

We explored various methods to mate the output of the Tesla to our BMW hubs. We couldn’t modify and reuse the original BMW axles as they would twist like paper straws under the high torque of the Tesla unit.

We turned to The Driveshaft Shop in North Carolina whose slogan is “We specialize in the impossible”, and for good reason. We sent them the inner portions of a pair of Tesla axles and a host of measurements. A few weeks later a beautiful new pair of Frankenstein axles showed up and bolted right in. The craftsmanship is stunning.









Beautifully crafted axles. They are completely new but the far right section which was out of a Tesla. The left end bolts to the BMW wheel hub and the right spindled end inserts into the Tesla drive unit.

*Control System*

On the rear deck of the car we temporarily set up all the gear needed to run the Tesla drive unit. 

To communicate with the Tesla unit are using the 057 Technologies control system. We believe that Jason and his team have put together the most elegant and capable unit. I evaluated the handful of other control systems before landing on the 057. I like that each 057 is directly paired to a particular Tesla drive unit with matching firmware. I believe that it is offering tighter, closer to native control of the Tesla unit than the others. This is, however, only my opinion based on my particular research and understanding. There are plenty of 057 critics who don’t like their direct pairing as it prevents you from purchasing the control unit separately (to control a Tesla drive unit you purchased elsewhere). As an Apple guy, I have usually preferred the power of closed systems, but that is a whole other argument. This is simply a matter of preference.

To further beat a dead horse, there is another strong reason I selected the 057 unit. Their device is a small box you hide inside the car and communicate with it any way you like. You can use simple buttons on your dashboard, or talk to it through a touchscreen that you can design as you like. All other controllers are touchscreen systems that you must install into your dash. They do not allow you to edit the look and feel of that touchscreen. As you can see from my early mockups of the interior, I have strong ideas about how I want the inside of the car to look and feel. I didn’t want to simply bolt on a generic looking touchscreen into the dash.









Our Jetson’s-inspired control panel, used for our early testing.









Here is our collection of control equipment L-R. (offscreen) our vintage control panel, 12v battery to power the three computers, 057 Tesla controller, precharge system including control board, resistor, and high voltage contractors, and accelerator pedal.

*We (Almost) Have Lift-Off!*

I must mention the days of troubleshooting once everything was all connected. Not to get overly technical, but there are a lot of variables in place and all of them have to go perfectly right for success. High-voltage from the Tesla battery modules, 12 volts from our car battery, the precharge system to properly ramp up high voltage into the Tesla inverter (part of the drive unit), the control module, accelerator pedal, axles, lubrication and more. 

We had issues not with some but with most of these things. Things as tiny as a bent pin inside the accelerator pedal, resulting in no communication to the unit. Both Tesla and 057 have safety mechanisms in place. If something reports an error, things generally don’t spin. We got pretty comfortable reading error codes from the Tesla unit on our laptop. 

This process itself was incredibly gratifying. Yes, we were frustrated and just wanted to see the wheels spin. But it delivered an unexpected gift of added respect for all the years Tesla (and all of the other) engineers spent developing and refining these automotive EV systems. To think that this should be easy is crazy. But equally crazy is that because of their work a guy like me can buy a bunch of parts from various sources and build such a classic electric sports car.

After all of the dreaming, engineering, fabricating and troubleshooting, we were finally able to experience the best day ever on this project and there were cheers all around.

Here’s a short little video: 







The day finally came when we were able to spin the wheels on the coupe for the first time.

Cheers,

Paul


----------



## brian_ (Feb 7, 2017)

*Re: 1974 BMW CSE*



jetdexter said:


> I can't get the embedded YouTube function to work- if anyone has some advice I'd love to hear it!


The forums embedded YouTube player - what you get with the YouTube icon in the graphic editor or the YOUTUBE commands - use Adobe Flash. That works for some users, but is blocked by some browser and operating system combinations, leaving only a big non-functional blank.

The straightforward links to YouTube videos work fine, so don't worry about (or try to use) the embedded player.


----------



## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*



brian_ said:


> The straightforward links to YouTube videos work fine, so don't worry about (or try to use) the embedded player.


That makes sense- thanks a bunch! I'll stick to the links.


----------



## brian_ (Feb 7, 2017)

*Re: 1974 BMW CSE*



jetdexter said:


> We explored various methods to mate the output of the Tesla to our BMW hubs. We couldn’t modify and reuse the original BMW axles as they would twist like paper straws under the high torque of the Tesla unit.
> 
> We turned to The Driveshaft Shop in North Carolina whose slogan is “We specialize in the impossible”, and for good reason. We sent them the inner portions of a pair of Tesla axles and a host of measurements. A few weeks later a beautiful new pair of Frankenstein axles showed up and bolted right in. The craftsmanship is stunning.
> 
> ...


Okay, the inboard stub is Tesla, but not the inboard CV? Do you know what CV joints were used? I wonder if they might be the very popular Porsche 930 type, a bolt-to-flange style for which a variety of flanges are available. What "level" in their axle system did you choose?


----------



## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*



brian_ said:


> Okay, the inboard stub is Tesla, but not the inboard CV? Do you know what CV joints were used? I wonder if they might be the very popular Porsche 930 type, a bolt-to-flange style for which a variety of flanges are available. What "level" in their axle system did you choose?


Sorry Brian I actually don't know where we landed there. After a couple conversations with Lee on the phone he recommended a setup based on my car/drive unit configuration. I know we discussed the 485HP that my unit would be equivalent to, along with the high torque. Axles and CVs aren't my universe, so I felt that I didn't have anything to contribute to the conversation. 

From my invoice:

"108mm Axle with 28 spline bar and 108mm CV's on both ends with Chromoly internals (Made with 14-1/4" 28/28 Spline Axle Bar) 
108mm Head for welding to CV's and Driveshaft Trans yokes 1018 or 1020 steel
Machine / Weld Tesla Inner to 108 Flanges"


----------



## brian_ (Feb 7, 2017)

*Re: 1974 BMW CSE*



jetdexter said:


> From my invoice:
> 
> "108mm Axle with 28 spline bar and 108mm CV's on both ends with Chromoly internals (Made with 14-1/4" 28/28 Spline Axle Bar)
> 108mm Head for welding to CV's and Driveshaft Trans yokes 1018 or 1020 steel
> Machine / Weld Tesla Inner to 108 Flanges"


Thanks 

Yes, it looks like the joints are the 108 mm diameter 6-bolt type as used widely in racing and modified applications. I think the 108 mm size is larger than what Porsche used for the 930 (1975-1989 911 Turbo, and the source of upgraded parts for many hot VWs), which is good because as impressive as that car was at the time, the Tesla drive unit can put out more torque. The 108 mm bits are Formula 1 worthy stuff (in the right grade, and with the high-speed boots).

The "bar" is the shaft between inner and outer joints, using the 28-count spline most common for these joints, regardless of what either the Tesla or the BMW would have had. The length of the bar is to suit the dimensions from the car and the width of the drive unit.

The Tesla stubs were machined off and welded to flanges, which in turn are bolted to the inner CVs.

The description doesn't explain what was done on the outboard end to mate the bolt pattern of the outer 108 mm CV body (six M10 bolts on a 94 mm diameter circle) to the BMW's stub axle. The CSE appears to use this style of CV joint; it seems unlikely to me that it would be the same size, but presumably this axle specialist has the sizing right.


----------



## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*



brian_ said:


> Thanks
> 
> The description doesn't explain what was done on the outboard end to mate the bolt pattern of the outer 108 mm CV body (six M10 bolts on a 94 mm diameter circle) to the BMW's stub axle. The CSE appears to use this style of CV joint; it seems unlikely to me that it would be the same size, but presumably this axle specialist has the sizing right.


Yes, that I all understood, it was your question of the CV that I really didn't know. The 94/108mm is the stock BMW hub. They used the 108 at the inner as well to match them up.

Clearly the CSL racing variant of the coupe that dominated in the early 70's was a beast. I assume they shared the same hubs as the street cars like mine, fortunately for me. I actually asked Lee about that while I was sending him all my measurements: "Will the hubs be a weak link" and the answer was no.

Thanks again Brian, you sure know your driveline That's what I learned about this group early... I assumed it would be full of "EV" folks more than car historians and enthusiasts, but I have been proven wrong many times. There's a great diversity of skills here across all aspects of autos, old and new.


----------



## brian_ (Feb 7, 2017)

*Re: 1974 BMW CSE*



jetdexter said:


> Yes, that I all understood, it was your question of the CV that I really didn't know. The 94/108mm is the stock BMW hub. They used the 108 at the inner as well to match them up.


The breakdown was as much an exercise in understanding the setup for me and getting confirmation, as information for anyone else 

After posting my comment I found the GKN Löbro website with their catalog, which has an excellent description of the various axle configurations which their parts support and which they can supply. In their illustrated list of axle assembly types, this is a Type 102, the first one shown... plus that custom Tesla adapter as a (in GKN's terms) "connecting device".

It's fortunate that the BMW uses such a common CV joint type and size, making this straightforward solution possible.

I'm more accustomed to front wheel drive vehicles, which have a non-plunging high-angle CV joint on the outer end and a tripod joint for high plunge on the inboard end, and rarely have a bolted flange anywhere in the shaft assembly; rear wheel drive like this tends to use a plunging low-angle joint at each end, and - I now realize - often have four bolted flange connections in each shaft.



jetdexter said:


> Clearly the CSL racing variant of the coupe that dominated in the early 70's was a beast. I assume they shared the same hubs as the street cars like mine, fortunately for me. I actually asked Lee about that while I was sending him all my measurements: "Will the hubs be a weak link" and the answer was no.


That is a nice feature. It turns out that according to the GKN Löbro catalog the 108 mm joint is "size 15", only midway up GKN's range of sizes and capacities.



jetdexter said:


> Thanks again Brian, you sure know your driveline That's what I learned about this group early... I assumed it would be full of "EV" folks more than car historians and enthusiasts, but I have been proven wrong many times. There's a great diversity of skills here across all aspects of autos, old and new.


There certainly is diversity, and I agree that's a good thing!


----------



## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

*Turn the Brakes Around*

Before we dive into our solution for the brake setup, Brett had a terrific idea to widen the area around the accelerator. The old transmission was so large that the tunnel took up a lot of space. When seated at the steering wheel, your right foot was essentially under the wheel rather than to the right. Since we have no transmission we thought we would widen the floor into the tunnel some. 









My daughter Maggie had been asking to help with the project so this was her perfect opportunity. There were no gloves small enough in the shop but I did have a face mask. She did a terrific job cutting away the steel!









After the floor was cut out Tyler welded in some sections and smoothed it out. Now we have a very comfortable space for both feet. I’ll go ahead and say it: No more two left feet. (You’re welcome).










Since we have no transmission, we have no need for a transmission tunnel. My idea is to install the brake booster here - backwards. We sourced a new Bosch Hydro-boost unit which will feed a new Wilwood master cylinder. 









Notice in the photo you can see where we took out some of the tunnel. 

Another issue we have with the BMW brake booster is that it requires vacuum. We have no engine to provide us vacuum. We could install a vacuum pump, but it makes more sense to move to a hydro-boost style booster. With hydro-boost, the power comes from the power steering pump. Since we have a 12 volt power steering pump to power our steering rack anyway, this becomes a very elegant and unified solution. 

In the photo you can see the brake setup installed securely, backwards, into the tunnel.

*Enter Greg*

At this point we have one huge gap in the essentials of braking. Connecting the brake pedal to the brake booster. What I call a lever, Brett named Greg.









Brett started with a piece of 3/4” inch steel plate and a plasma torch. He had made a guide and could just ride the torch along for a perfect cut.









The plasma torch provides some terrific looking metal artifacts.









We heated Greg up a few hundred degrees where he gave up his strength and we could twist him into the compound shape we needed. Once the shape was achieved, we evenly heated Greg up to get his particles all in harmony for strength.









After the cutting, cleaning, twisting, heating was done Brett welded ends on it, and the pivot point. He attached a very strong receiver to the firewall and we now have a terrific braking solution which takes up less than 2 inches of the engine (battery) compartment. 









After all the designing, sourcing, fabricating, and installing, the truth will be in the pudding when we connect the brake lines to the wheels and give Greg a whirl. Stay tuned for that.

Cheers,

Paul


----------



## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

*Battery Box*

Unless we plan to drive our car using a very long extension cord, we have to get our battery modules off of their cart and into the car. Our plan is to get the majority of the modules in the engine bay, with a couple more in the trunk. Here’s the story…

I've discussed earlier in this thread that while we were tempted to use Chevy Volt battery modules in order to get by with far fewer, smaller modules we simply wanted to shoot for 200 miles of range. Our car is far lighter than a Tesla Model S, but far less aerodynamic. Still, in a 72kWh configuration, when Tesla gets 240 miles of range on the highway, we are expecting to see 200 miles of mixed (as I will be doing mostly mixed city driving on my day-to-day use). I may be way off, but here's hoping...

*Starting with an Open Engine Bay*










We now can benefit from all the work we have done to open up that engine bay: The bulky steering box and linkage that we swapped out for our compact and low steering rack; The large brake setup which was swapped out and relocated into the transmission tunnel (thanks to Greg). We have earned ourselves a very wide open area for our new battery box.

*A Sheet of Aluminum and a Table Saw *

To properly mount and protect the battery modules inside the engine bay we need an enclosed box. To keep the weight down as much as possible, we built our battery box out of aluminum. By using all the space possible, our box will hold 12 Tesla modules. We will need to put 2 more modules into the trunk.









Aluminum cuts smooth and easy on a tablesaw as if it were a piece of thin plywood.









Tyler is a master with the tig welder. I learned a lot about welding aluminum on this project. Very tedious.









In between the car’s frame rails we are able to squeeze in a lower section holding two battery modules.









Here is our lower section complete with the modules slid into their tracks.









The full box is starting to take shape. We are able to get 9 modules across in the main body of the box.









Here you can see the 3 tiers of the box: 2 on the bottom, 9 across the center and 1 more on top.

continued...


----------



## jetdexter (May 30, 2018)

...continued


*Load it up with Modules*

Once the box was complete we then loaded it up with our 12 modules. We used a combination of 2/0 copper wire and copper bus bars. The wiring chain begins and ends in a junction box that was built into the bottom, and accessible under the car.









Here’s an example of a custom bus bar which connects the two bottom modules in the chain. It looks rough now but will be plated and dipped in orange to look like the ones in the next photo.









This photo shows the 9 modules across looking nice with custom bus bars. Also the cable running to the top module and down to the junction box.









Each corner of the box has brackets to secure it to the car. The corners of the box are steel reinforced on the inside for this purpose and also for living the box.









A little bit of logo work and the box looks very nice in the car. She comes in around 750 lbs. That’s about what the stock drive train and accessories, so the car is comfortable with the weight. 









Very tidy underneath. You can see that we used every inch of space. If you look close you can see inside the junction box. A fuse is inserted as well. Any electrical short behind the box will blow the fuse - not the modules.









Finally, we installed the 2 last modules in the upper trunk area. This leaves plenty of trunk space. There’s even room for one more module if we ever get the desire for “more”.

*Close it up and Lift it in*

Here’s a short video showing how the doors attach and how the box lifts to easily drop into the car- all 750 lbs of it. 

https://youtu.be/5g8GYO_5qHE

This battery box was far more work than we ever anticipated. But it turned out terrific and well worth all the efforts. This brings us extremely close to driving the car around the building. Stay tuned!

Cheers,

Paul


----------



## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

*Untethered*

It’s been several months since we spun the rear wheels with the Tesla motor. When we did, the batteries were stacked in our wooden crate with a very large extension cord going to the car. Since then we have installed all of the batteries and accessories into the car, so we are able to run the car self-contained.

*Finish the Trunk*









Last time you saw the trunk it looked something like this photo - a gaping hole in the back of the car. Before we can move forward we need to finish out the trunk so we can keep the water out and the golf clubs in. 









First we install the upper trunk floor. We had grand ideas of this section being plexiglass so we could show off the Tesla motor from up above. But batteries need to be installed into this area, so we put in a steel floor.









For the lower trunk floor Tyler started with creating a cardboard template of the trunk shape.









He then traced it to a sheet of steel, then cut the shape. Just like in 2nd grade art class, but don’t tell that to Tyler.









Tyler created ribs using a hammer and chisel. Ribs add rigidity and strength to an otherwise flimsy piece of sheet metal.









Now it’s starting to look like a professional car part.









She drops beautifully into the car to create a clean floor. The sections without ribs are where our devices will be mounted.









Next up is the vertical piece that connects the upper and lower trunk floors.









The panel fits nicely and is ready to be welded in place.









But first we add square tube supports which will support the weight of the equipment, while also reinforcing the rear of the car.

continued...


----------



## jetdexter (May 30, 2018)

...continued









We now have a complete enclosed trunk.









Here is the trunk from under the car. The motor now feels like it has a home, rather than hanging there exposed.

*Install More Equipment*

Now that we have a trunk, we can install the rest of the EV devices which will sit in the lower trunk section. There will be a carpeted false floor installed on top of this equipment, similar to the panel that hides a spare tire in many cars.










*Here’s what we’ve got back there:*

*1 - 12v “car” battery. *When the ignition is turned off, our Tesla batteries are disconnected from use. We need a small 12 volt car battery to power things like dome lights and other accessories. When the Ignition is turned on, the Tesla batteries effectively charge this car battery the way a traditional alternator would.

*2 - 057 Tesla Drive Unit Controller.* This 3rd party unit talks to the Tesla drive unit controlling speed, power limits, cruise control, and much more. There is more information about the 057 in a previous post.

*3 - DC/DC Transformer.* This box receives high voltage from our Tesla batteries and converts it to 12 volts DC. It charges our car battery while powering traditional essentials such as headlights, power steering pump and more.

*4 - HV Junction Box.* Just like it says- it is a junction receiving the high voltage from the Tesla batteries, the AC voltage when the car is plugged in to charge, and sends that power to and from the charger, the DC/DC converter and the Tesla Motor.

*5 - Tesla Charger.* This unit receives power when we plug the car in to charge. The unit converts and controls the input voltage as needed to properly charge the batteries. (Another computer will be added to control this unit).

*6 - 057 Precharge Unit.* This unit automates the precharge of the Tesla drive unit’s DC/AC power inverter. This is a temporary unit, whose function will be rolled into our eventual Battery Management Computer (BMS).

*7 - HV Contactors.* These devices switch on and off the high voltage power to the Tesla drive unit as we turn the ignition on or off. These units will be covered for safety once our charge port is installed into the old fuel fill door above. 

The orange high voltage lines are complete, but the low voltage wiring is temporary. Much will be done with fuse block, relays, multi-connectors and such for a clean final result.









Here's a shot of our graceful cockpit with our custom control panel. It’s a long way off from performing any date night duties, but it’s beautiful to me. 

And here's a little video of us spinning the wheels untethered:

https://youtu.be/1H0OAxUakh4

Now for the last bit of work on the brakes then we can drive this thing around the building!

Cheers!

Paul


----------



## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*

We finally drove the coupe!










Here's a little video of the first drive:

https://youtu.be/TqBZDaT1Zwo

We kept it pretty slow for these first runs, staying under 30MPH for now. After we give her a close looking over we will take her out more adventurously. I will say that the steering felt fantastic. The balance on the turns felt nice, but we were keeping it slow so we don't know nearly enough there yet. We know we have more weight beyond the axles than we would prefer, but our goal of a 200 mile range car required some compromise. Very interested to see how she does at speed in corners.










Finally- sorry for the BLAST of posts the last couple of days. It took a string of posts to catch up to our progress over the last several months, but this is where we are as of early January. 

Now we move to a lot of tuning. We've got to install and plumb our power steering pump. We need to install our radiator(s) and plumb batteries, drive unit, charger and DC/DC converter (That's going to be a challenge). We have to configure our BMS so we can safely charge and run our batteries. 

We will do some of these things this month with the car in its current state (That is, anything requiring cutting and welding). Others we will do after she comes back from being painted, so that we only have to do it once.

Mostly, it feels great to have made it this far!

Cheers,

Paul


----------



## brian_ (Feb 7, 2017)

Wow, Greg the brake lever is tall! It would be nice to be able to move the brake pedal pivot to inboard of the steering column, with the pedal shifted inboard as well (but less) to follow the accelerator pedal. If Greg were shorter, he would be lighter and stiffer... and it would be nice to have less gap between the two pedals which are both run by the driver's right foot. But even at this length, it's an interesting solution.

The more common way to transfer pedal action, used commonly for clutch actuation (before everyone went to hydraulics or cables) and even to run a brake master cylinder on the opposite side of the car from the driver (due to conversions between left-hand-drive and right-hand-drive), is a horizontal shaft with a crank on each end (the one on the pedal end can be the pedal arm itself). Instead of bending stress on a long beam, it has torque on a tube; instead of twice the pedal force applied to one pivot, it has the pedal force applied to each of two bearing locations. More common doesn't necessarily mean better, of course.


----------



## brian_ (Feb 7, 2017)

jetdexter said:


> A little bit of logo work and the box looks very nice in the car. She comes in around 750 lbs. That’s about what the stock drive train and accessories, so the car is comfortable with the weight.


The front battery pack is similar to the engine and transmission, but the drive unit and rear battery pack are more than the original final drive and fuel tank, so I assume that there is a significant but manageable increase in total weight.



jetdexter said:


> The balance on the turns felt nice, but we were keeping it slow so we don't know nearly enough there yet. We know we have more weight beyond the axles than we would prefer, but our goal of a 200 mile range car required some compromise. Very interested to see how she does at speed in corners.


In mass distribution, that shift outward is the handling concern: the centre of the front battery pack is further forward than the centre of the mass of the engine and transmission, and the drive unit is further rearward than the final drive and probably even further rearward than the centre of the final drive plus fuel.

This is a pretty common consequence of a conversion. As long as expectations for handling are moderate, it should work fine.


----------



## brian_ (Feb 7, 2017)

*Re: 1974 BMW CSE*



jetdexter said:


> Here is our lower section complete with the modules slid into their tracks.


It may just be that some photos are of the incomplete box, but are all of the modules on tracks? My understanding (which may not be correct) is that the Tesla Model S/X modules are supported by rails in grooves on the long edges of the modules, and that the top and bottom covers can stand the modules being stacked on a shelf, but are not structurally suitable for support in the vehicle.


----------



## brian_ (Feb 7, 2017)

jetdexter said:


> Once the box was complete we then loaded it up with our 12 modules
> ...
> Very tidy underneath. You can see that we used every inch of space.


The packaging here is very impressive!  That's an astounding amount of battery in an engine space.

It would be really nice if everyone had a chance to put their car up on a hoist and take clear photos like this of the conversion and resulting configuration.



jetdexter said:


> This photo shows the 9 modules across looking nice with custom bus bars.


Very nice. But did you consider alternating the orientation of the modules so that the interconnecting bars could be shorter?



jetdexter said:


> Each corner of the box has brackets to secure it to the car. The corners of the box are steel reinforced on the inside for this purpose and also for [lifting] the box.


Looks solid. How did you handle the combination of aluminum and steel? If they're just clamped together directly, it's a electrolytic cell waiting to happen.


----------



## jetdexter (May 30, 2018)

brian_ said:


> Wow, Greg the brake lever is tall! It would be nice to be able to move the brake pedal pivot to inboard of the steering column, with the pedal shifted inboard as well (but less) to follow the accelerator pedal. If Greg were shorter, he would be lighter and stiffer... and it would be nice to have less gap between the two pedals which are both run by the driver's right foot. But even at this length, it's an interesting solution.
> 
> 
> 
> The more common way to transfer pedal action, used commonly for clutch actuation (before everyone went to hydraulics or cables) and even to run a brake master cylinder on the opposite side of the car from the driver (due to conversions between left-hand-drive and right-hand-drive), is a horizontal shaft with a crank on each end (the one on the pedal end can be the pedal arm itself). Instead of bending stress on a long beam, it has torque on a tube; instead of twice the pedal force applied to one pivot, it has the pedal force applied to each of two bearing locations. More common doesn't necessarily mean better, of course.



Brian, those are interesting observations to be sure. We did explore the hydraulic solution but I just didn’t want to get involved with more fluids to deal with. We did not explore the shaft method though, which would be interesting to see if that could have worked. 

We did try to get the brake pedal to the right of the steering column to shorten Greg, and also tried to get Greg inside the firewall. But neither of those would work in terms of placement, with all the tin mockups we explored.

I was nervous to feel heaviness but in pumping brakes and in driving it feels as light and tight as my modern cars, so I think I am happy with it. There is certainly no flex, but it was the weight I was worried about. This will all get even lighter with the booster helping with power.


----------



## jetdexter (May 30, 2018)

brian_ said:


> The front battery pack is similar to the engine and transmission, but the drive unit and rear battery pack are more than the original final drive and fuel tank, so I assume that there is a significant but manageable increase in total weight.
> 
> 
> In mass distribution, that shift outward is the handling concern: the centre of the front battery pack is further forward than the centre of the mass of the engine and transmission, and the drive unit is further rearward than the final drive and probably even further rearward than the centre of the final drive plus fuel.
> ...




Yes no position to defend here though I will say that our drive unit and batteries are only about the 10% heavier than the very heavy differential, spare tire, and fuel tank. But actually further forward (as the fuel tank and spare were flung completely to the bumper). Our two battery modules are pretty high though. I had a few folks recommended putting them in the lower section. (Lower center of gravity versus center of car. I opted for further forward).

Regarding the battery box, it is further in front for sure, but not as much as it appears. Most of the modules are a few inches from the firewall with a lot of space in front. The box is far deeper for just the two bottom modules to extend forward. 

I’ll learn a lot more as I start test driving at speed. I have managed expectations. I am not looking for a track car to be sure, but I do need it to behave. I am optimistic


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## brian_ (Feb 7, 2017)

jetdexter said:


> Yes no position to defend here though I will say that our drive unit and batteries are only about the 10% heavier than the very heavy differential, spare tire, and fuel tank. But actually further forward (as the fuel tank and spare were flung completely to the bumper). Our two battery modules are pretty high though.


Including the spare does change the comparison, and keeping those two modules forward helps the longitudinal distribution.



jetdexter said:


> Regarding the battery box, it is further in front for sure, but not as much as it appears. Most of the modules are a few inches from the firewall with a lot of space in front.


Yes, but the entire transmission was behind the firewall. Not a huge deal, just one of the contributing factors. This isn't as extreme as the common conversion technique of keeping the transmission, plunking a massive DC motor where the engine was, and stacking modules all the way to the grill. 

Has the car been back on the scales yet? I realize that the bodywork and interior are not complete yet.


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## jetdexter (May 30, 2018)

brian_ said:


> Very nice. But did you consider alternating the orientation of the modules so that the interconnecting bars could be shorter


I hadn't thought of that, but getting between them to bolt terminals is very rough as it is. If there were two opposing each other with a little loop I am not sure you could get to the second side. Doing it this way you always have a bit of space opposite where you are bolting. That is a very interesting idea though worth checking into for another build.



brian_ said:


> Looks solid. How did you handle the combination of aluminum and steel? If they're just clamped together directly, it's a electrolytic cell waiting to happen.


No clamped connections. Any interaction with steel in the box is bolted. All the steel will be coated and painted to minimize this opportunity - as well as them being in a very dry box.


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## jetdexter (May 30, 2018)

*Re: 1974 BMW CSE*



brian_ said:


> It may just be that some photos are of the incomplete box, but are all of the modules on tracks? My understanding (which may not be correct) is that the Tesla Model S/X modules are supported by rails in grooves on the long edges of the modules, and that the top and bottom covers can stand the modules being stacked on a shelf, but are not structurally suitable for support in the vehicle.


Brian,

Yes you are correct in both regards. And yes, all the modules are sitting in tracks. We used 3/8" x 3/4" aluminum (if I remember correctly) with a groove cut into them. In the photo of the box with 3 modules in it you can see a batch of these strips running front to back ready to receive the vertical modules. 

In the closeup photo of the custom copper buss bar you can see the welds we put in the ends as a stop. The opposite ends have bars that unbolt to let the modules in or out. 

Also, the photo that shows the very top battery resting on it's belly: There is a battery support for that unit before the end cap goes on the box. It holds that module by the rail as well. The support was just missing for the photo.


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## Tremelune (Dec 8, 2009)

This is an incredible amount of work! I feel like the fun bit starts around now...There will be setbacks. Keep going!


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## jetdexter (May 30, 2018)

Tremelune said:


> This is an incredible amount of work! I feel like the fun bit starts around now...There will be setbacks. Keep going!


Yes, you seem to be right about that. My strengths are pretty broad yet very shallow . I know a little bit about a lot of things, which is what has allowed me to take on such a project. But I am probably stronger in the area coming ahead. I am a bit better dealing with wires than I am plates of steel. So it has been a very enjoyable few weeks since the last update. 

For example, I got my Brembo/Tesla parking brake calipers rewired into a proper controller (up till now I was just hot-wiring them and carefully engaging them without overdoing it). I am using the Pantera Electronics controller which works fantastic. Not a huge fan of the plastic box he put the assembly into, I will probably rework that. The heavy gauge leads in and out have to pass through the lid, which only snaps on, so any tension at all pops the lid off. He makes a few variations, but mine uses a simple single trigger input to engage. I will connect it to the park position of my shifter, so that whenever I put it in park, the brakes engage (like a Tesla and others).

I also cleaned up my temporary "Just want to drive the car" mess of wiring into a still temporary but serviceable solution with fuse block and terminal strips. My eventual plan would be a more OEM style wiring harness with multi-connects and such. But this will do just fine for the next few months of testing and refining.



















We've also done a lot of refining of the dash display. It's amazing how many hurdles we had to jump through to get a nice solid connection, and fluid, reliable feedback. But it's been worth the efforts as we now have a very nice dash display working. My final display will be shown through the stock BMW Tachometer gauge hole in the dash. I want to preserve the classic look of the car. But for now this display is also a touchscreen controlling various aspects of our 057 controller.

Here's a little video showing the progress.


https://youtu.be/w7PYgomvSP8

All that and I found a hack to get a video preview image in this forum

Thanks guys fro the helpful comments, and the priceless information I have silently dug up in the threads here. 

Cheers-


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## Tremelune (Dec 8, 2009)

> My eventual plan would be a more OEM style wiring harness with multi-connects and such.


What's your plan for this? My wiring looks like your wiring currently. I was going to either steal the Nissan Leaf harness fusebox I had lying around, use one from a ~2000 Chevy Impala that this video discusses, or piece one together with DillBlox, Deutsch connectors, and a junction box.

The OEM stuff doesn't allow for much customization (my project seems to need a couple unusual relays), and the DillBlox stuff winds up being a bit more compact the more fuses/relays you use, but...it's hard to argue with free stuff lying around. I'm not sure if I'll have the space for some of the bigger Leaf boxes in the end.



> It's amazing how many hurdles we had to jump through to get a nice solid connection, and fluid, reliable feedback.


Can I ask more about this as well? I'm using hand-twisted 22-20 AWG wire or CAT5e for my CAN wiring, and I'm not taking great pains to keep the twists near the ends. I'm kind of just taking it on faith that it will work for 6-foot runs when all is said and done.


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## jetdexter (May 30, 2018)

Tremelune said:


> What's your plan for this? My wiring looks like your wiring currently. I was going to either steal the Nissan Leaf harness fusebox I had lying around, use one from a ~2000 Chevy Impala that this video discusses, or piece one together with DillBlox, Deutsch connectors, and a junction box.
> 
> The OEM stuff doesn't allow for much customization (my project seems to need a couple unusual relays), and the DillBlox stuff winds up being a bit more compact the more fuses/relays you use, but...it's hard to argue with free stuff lying around. I'm not sure if I'll have the space for some of the bigger Leaf boxes in the end.
> 
> ...


So I have an AV/IT background and I started out with a couple of different cables that were just not providing a reliable connection. So I started digging and wound up sourcing 50 feet of actual CAN bus cable, which is 120 ohm, twisted and shielded. I am connecting ground on only one end of course (My raspberry Pi CAN interface). But I am running a good 12 feet from my trunk to the dash. What I hear is that 1 meter is easy- use lamp cord if you like  But once you get over that it gets iffy. But your 6-foot run could be VERY fine with CAT5. Using just one of the twisted pairs I assume, not one wire from two pairs

I hope this answers what you were looking for!


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## jetdexter (May 30, 2018)

Sorry I quoted you incorrectly  But my first answer is up in there within your quote...


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## blwnhr (Apr 4, 2019)

I just stumbled upon this thread, a fine project, please keep posting updates.

Is your drive unit a regular Model S/X or is it a P(erformance) unit?


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## brian_ (Feb 7, 2017)

blwnhr said:


> Is your drive unit a regular Model S/X or is it a P(erformance) unit?


I don't think there's a difference. Model S/X drive units come in two sizes:

small, used at the front, and at the rear of non-Performance AWD variants
large, used at the rear of non-Performance RWD and Performance AWD variants
Other than this motor size, power differences between variants of Tesla Model S/X are the result of battery and software differences.

This car is using a large drive unit.


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## jetdexter (May 30, 2018)

blwnhr said:


> I just stumbled upon this thread, a fine project, please keep posting updates.
> 
> Is your drive unit a regular Model S/X or is it a P(erformance) unit?


Yes as Brian said the only real difference is between large and small drive unit, and I am using the large. However, I am using the 057 Tesla controller, which is a fantastic unit. They mate the controller to the Drive Unit and have a few configurations- some of which allow for more power. (Which to be totally honest, means that they are simply limiting power in the units that produce less power, but that's not how it's advertised). 

That being said, I am using the unit between their base and performance unit. Which produces in the neighborhood of 475HP with full voltage. I am running 14 Tesla modules, so I won't get all of that, but plenty to be sure. 

Glad you appreciate the project. It is amazing to drive on the roads now that we have gotten it this far!


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## blwnhr (Apr 4, 2019)

jetdexter said:


> Which to be totally honest, means that they are simply limiting power in the units that produce less power, but that's not how it's advertised.


Yes, it's difficult to get a straight answer on this, some say they P units have different AC/DC inverters to facilitate the extra power, some say it's all software. Honestly it doesn't make sense for Tesla to manufacture two different inverters, especially when it's so easily controlled in software.

For reference I'm collecting parts for a conversion using the large drive unit and I'm chasing the most power I can. I purchased a complete rear subframe (brakes, suspension etc.) less drive unit as I wanted to do some more research before purchasing the drive unit.

Thanks for getting back to me.


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## jetdexter (May 30, 2018)

Yes of course. And I was interested in using the whole subframe for it's modern suspension as well as the brake setup and handy motor mount built in  But my car was far too narrow to be able to use it. 

I might be converting an 80's Rolls Royce which could take great advantage of that. I'm not looking for a new line of work, but since starting my car people seem to be calling. I'm converting another BMW 3.0 for one guy now- we are halfway done with it (using a small drive unit as he didn't want gobs of power, and conserve some weight for batteries as they are about 100lb lighter). And now there's a guy who grew up with a Rolls as a kid but drives a Tesla now, so there you go.


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## blwnhr (Apr 4, 2019)

jetdexter said:


> But my car was far too narrow to be able to use it.


Yes, my car is 8" too narrow (to standard track and I'd like some "dish" so more like 10" needs to come out). I've developed a replacement subframe design that utilises all the original Telsla suspension and geometry, it just requires shorter axles (uses Tesla CV's both ends) and a short coilover.

Anyhow, I'm muddying up your thread. Top work, will continue to follow with interest.


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## jetdexter (May 30, 2018)

I haven't posted an update for a while but I've continued to make progress on the coupe. 

Got the air dam on (which came with a free crack on the front which opened up as soon as it was screwed on). We temporarily fixed it and will have to do a proper repair when the car goes to paint.










She’s looking better and better every day!

We took her on our furthest run yet and got into some twisty turns at speed. The steering and the front weight felt good, but I’m looking for much more testing there. I’ll take her to a track to discover the limits. She’s a daily driver but I do want to know exactly where I stand with her after all the modifications. That’s what I did with my first 911 so that I could find out exactly when I should expect to be going backwards

It’s pretty intoxicating behind the wheel, that’s for sure.


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## jetdexter (May 30, 2018)

Amid the world ending, I’ve been able to make some nice progress on the coupe. Even though we are only prepping it for a couple months of testing and refine the Tesla, steering and brake modifications (then take her back apart to paint) we couldn’t help ourselves but to put the complete trim on the exterior. Most of the trim was in rough shape (no surprise there but we got it all on. Really glad we did too because we kept discovering body issues along the way that we worked out. 










It sure is nice to see her looking good- and it’s fun that there isn’t a drop of bondo on this car right now. Just clean straight metal. 
Now that’s she’s fully licensed and insured I am venturing into traffic situations (and yes. California still has plenty of traffic even during the crisis. Lucky for me I was self-isolating inside the coupe).

All of the outside trim is now in place along with brakes and turn signals. I put in a 3rd brake light in so I could tell my wife that the car has modern safety features. I do appreciate my modern seats and seatbelts. They aren’t harnesses but I do feel very confident in them.

The biggest addition is the new bumper. Like everything else that came on this car my original bumper was beyond bringing back. When they federalized the car in 1993 they had a four-year-old weld the steel section and center mount support in place. Gobs of weld were everywhere. But even aside from that the bumper would’ve cost a year of college tuition to have straightened and re-chromed.

Lucky for me there’s a guy who bought an early bumper then straightened and re-chromed it to put it on his 2002. When he then found that it won’t fit his 2002 he sold it to me 

It looks mighty good on her. It looks even better against the photos with the old bumper

Cheers,

Paul


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## jetdexter (May 30, 2018)

Last week I got some work done on the digital display that we will be fitting into the old Tach position. I want to leave the vintage look of the wood instrument cluster, and I intend to use the speedo, temp (for hottest temp of battery or drive unit) fuel gauge (for battery life) and clock. But the RPMs is the only thing that has no value to us. So I am fitting a display into that position. 

The rectangular display you've seen in previous posts is great for testing, but I am now working on a square display I sourced on Alibaba into that position.

I learned the art of 3D printing and created some mounts for the unit and have her installed. I still have to install a video driver board behind the display- those are being printed as we speak. 



















And here is a super short video of how it all came together HERE:


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## jetdexter (May 30, 2018)

It's been forever since I've updated this thread, but I have made a lot of progress on the coupe. I will try to catch up and post the last few months progress here over the next few days.

For the cooling system, I am using a Kawasaki 1000cc radiator with a Bosch pump and a small reservoir. The 3/4" hose runs first to the Tesla drive unit, then into the Tesla DC/DC converter then back to the reservoir. We will also pass through the Tesla charger (which is near the DC/DC converter) but we haven't yet begun to use the charger so I'm not bothering with that for now.

Tyler cut in the reservoir behind the passenger side headlights. The radiator fills it up and the pump draws from it. It's amazing how that pump will NOT keep prime unless gravity is forcing water down its throat. We struggled with this a lot until I found placements for everything that did just that. Even then you have to squeeze the hoses to force water through that pump. But once it's primed it works perfectly with a nice flow (I am able to watch the flow as the water level is just below the inlet into the reservoir). 











And here's our little radiator. Electric fans are behind it. The battery box is just behind that, but there is gap to force air below.











On the inside I had threatened to install the E93 rear headrests. You might remember I am using E93 (convertible) seats because this is a daily driver and I really wanted the integrated seatbelts and security. Anyway, I purchased the front seats as a set with rears, so I wanted to install rear headrests for when I take the kids to school. Brett did some handiwork and they are now installed.

Here's a B/W photo because the headrests are black and the seats blue (for now).












Finally, we have gone Keyless entry While I love the look of the old key, I have a modern steering column/key, and with all the technology I figured why not go keyless? Besides, I missed the whole 50's and 60's when that was what you did to your hot rod. So now was my chance...











Cheers,

Paul


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## jetdexter (May 30, 2018)

Sound Deadening- We sprayed topcoat to the inner doors and floors then applied DynaMat to the entire surfaces. I'd say it's around 40lbs worth, but completely worth the weight and effort. The feel of the car is so tight now, which is dramatic when driving. Our custom seat mounts look much more finished painted and poking through the material. We will wrap up this work next week.
































Digital Dash Display- A few weeks ago I posted the progress of physically mounting the color digital dash display. With a lot of perseverance with video scaling, and nice work from Jeff on Raspberry Pi programming, I was able to finally get the mounted display to show our live information from the Tesla unit. There is some fine-tuning to be done, but it's just about there. The photo makes it look like it is brighter than the other gauges, but in real life, it blends in far better than I had even hoped. Very excited for how this came out. Currently I am working on converting the Speedo, Temp and Fuel gauges to Stepper motor control so that we can have the classic gauges telling the modern information.












Dash Work - I wouldn't be able to bring the car within 10 miles of home with the dash looking like this:











I came across a guy on eBay who was amazingly local who had purchased a set of Leather wraps for an E9 dash- but then had sold his car before installing them (buying the parts is always the easy part Remember that I am using E93 leather seats, so I took a bunch of photos of my seats and met the guy to see if the leather would match. 

It must have been my lucky day, because it was perfect. When I brought them back to the car I can't tell them apart. The funny thing is my upholstery guy can't find as close of match in all his sample books And the stitching is the same as well. I picked it up for a couple hundred bucks. 











Of course my Upholsterer wasn't quite that cheap, but he is my neighbor where my shop is and he was very kind to me. They had to first do a lot of repair to the dash. The instrument section was split open to twice it's thickness where it meets the wood. One of the mounting screws was broken off, and cracks everywhere. They did an amazing job at the repairs, then a wonderful job at the wrapping. 


































To celebrate the efforts we took the car out for our longest drive yet. Much further away than we could push her home if she broke down, that's for sure We drove to Norms and got lunch- the first day that restaurants were open in California! Then we took her for a 25 minute drive along the So Cal freeways. The car felt terrific at 80MPH and on the high-speed ramps. Can't wait to do more of that. It's probably the quickest E9 that's ever been on the road, but who's keeping score. It's certainly the stealthiest, since it is perfectly silent when getting up to speed in a few seconds. It is completely well-behaved too. 





















All in all, it's been a very exciting week, and I might be just a few weeks away from bringing the car home and driving it to work most days!


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## jetdexter (May 30, 2018)

I started working on the analog gauges. While the digital display in the old Tach position is nice, I still want to see the traditional Speedo, Temp and Tank gauges function (along with the clock of course).

The speedo took some patience for this hack engineer. A lot of measuring, 3d printing, then remeasuring, then printing, etc. But I've got it working and it's fantastic. I took the speedo apart, removed the mechanism. 












Using a common Stepper motor (this model is used by several manufacturers) I needed to extend the shaft to reach our needle (since it passes through the Odometer). Also, our shaft is larger diameter. I cut off our old shaft, then printed a small extender section which very snugly creates a nice single unit. 












Then I took some circuit board and cut out a shape that would fit. I installed a small motor driver board, then wired up the motor to it, and our leads which will exit the cluster, and wrapped those nicely.




















My 10th iteration of this mount worked perfectly. None of the holes are really aligned to anything, so it was tough to find a reference, but PLA material is cheap and recyclable so I just kept printing and adjusting until I got this nice mount. There is a top cap which then bumps the top inside of the can. 












Next up was the Odo. I do not have a transmission to feed me miles, so I have to do it electronically. Once removing two layers of worm drive, you are left with this 22 tooth gear. (22 spoke for this unit, the older unit I landed on using is a 19 tooth gear). I printed up a shaft that surrounds this gear on one end, and the output of a stronger, geared-down stepper motor on the other. 












Here's a nice shot of an old and new (at least that's my assumption) of debossed printed unit and flat printed newer unit. Both with very low miles I might add. I am going with the classic unit. 











I had to cut away the side of the can for the motor. It is a tight fit to the next can, but it works well. The motor very slowly, and very smoothly turns the odo. Notice the driver board fo this motor inside this cap.











After everything was assembled, it is all enclosed in this cap. This is a first iteration, so it should be cleaner once complete.










After all that was done, I am now forging my way into the Temp/Tank gauges. Pretty good progress there, but only one pic so far. I'll get those dummy lights working as well. I don't even know what they all originally did, but I might change that up anyway. For sure, a high temp, a low fuel (battery), but I don't know the others. I'll leave the original printing alone, and just insert LEDs in the tunnels. 












Oh- one more thing. I did buy a couple cans of vinyl dye spray, and paint my aging blue rear seats and door cards black for my temporary solution. The rear seats also had terrible sun damage so I used large sections of patching tape to seal them off. It's not perfect, but it will get me by until I can reupholster the whole interior. 

It's fantastic to have an interior that is all the same color! The rear headrests now match the seats as well. 












That's it for now. 

Cheers!

Paul


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## jetdexter (May 30, 2018)

We got the power steering and power brakes functioning. If you've followed this thread, you are aware that (for better or worse) the steering and brake setups were completely re-engineered. Mostly to make way for the Tesla battery box in the engine compartment. We installed a VW GTI power steering rack, a Bosch hydroboost brake booster, a Wilwood master cylinder and big brake setup.

Since we have been driving the car the last 6 months, we have ran these systems without power. Steering felt fine on the road, but turning those big tires in a parking lot was just as you would expect. Brakes were very weak since the setup simply requires boost to properly function. Lucky for us, the strong regenerative braking of the Tesla setup means that you step on the brakes _very_ rarely. If you have ever driven a Tesla you would agree that there are many drives where you simply don't put your foot on the brake at all other than for a full stop.

We have sorted out so many details with the conversion that it was finally time to tackle this one. To power both steering and brakes I had selected a BMW/Mini 12 volt power steering pump. It fit nicely between the PS rack and the bottom of the firewall. I gave it the 100amp service it wants (30 amps constant, but it will pull 80A or so if a soccer mom were to hold the steering at limit for extended periods of time).











The pump feeds the brake booster, which then feeds the power steering rack, which feeds the reservoir which feeds the pump. This all looked really good on paper a year ago, but I have been cautiously optimistic that it would all function and feel nice. I had done a lot of research, based on parts of this design working with other parts of other designs, but there was no real comparison as a whole.

Installing the pump was easy- we've done a lot of that. Fabricating brackets from various nearby mounting points, which mate to the Mini pump. Running the electrical was easy, but when it came to the high pressure lines I was literally lost. Tyler (who you know as the metal finishing master from this thread) called a mechanic buddy who told him of a guy he had heard of who used to work at Mesa Hose, a local hydraulic hose shop. Tyler called them and they said "That's Mike, here's his number". I'd never heard of Mike, but he and his dog Stanley live in Nebraska and come out a few times a year to work on very nice hot rods for a few weeks at at time. He and Stanley were busy with a project but couldn't resist the story of this Tesla BMW, so he came by the next day to check it out. He instantly knew all the devices, connection sizes, etc. He measured for what he would need and said that he could come back after the weekend to fabricate and install the hoses at our place.











Mike fabricated the custom braided lines and fired it up. We bled the system (which requires several repeats of letting the bubbles die off with long delays). In the end we now have fantastic brakes. The stock brakes were already amazing for their day, but I am quite proud of this setup which feels wonderful and stops the car immediately. I feel like they are a great match for the type of Tesla conversion we've got going here.

The steering feels good, but I need more drives to see if it might be a bit soft. If so, Mike will do what VW does, which is insert a thin sleeve into a hose to reduce the pressure before the rack. It is suprising that there is not an adjustable valve (there may well be but Mike hasn't come across one that handles this high of pressure). Inserting sleeves is what manufacturers do for reliable pressure reduction. Once again- this is not my world, but I find it fascinating.

While all of this was going on we were able to get our gas-charged struts in place to hold the hood up. I think this gained us about 40 pounds from the front of the car as the revered stock system is quite weighty. I'd read some threads here which had used some various designs. Some more obtrusive than others. I think that mine are quite out of the way. Of course the only thing I even need to do under here is check my 3 fluids.











That's it for now-

Cheers,

Paul


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## Tremelune (Dec 8, 2009)

This build is wild, man. I love seeing the technical details of the custom finishing stuff—speedo and what not. My car is on the road, but pretty much gutted at the moment...I look forward to nicing it up.

If I may ask, who's "we"? Are you a shop? Just someone with a garage?


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## jetdexter (May 30, 2018)

Tremelune said:


> This build is wild, man. I love seeing the technical details of the custom finishing stuff—speedo and what not. My car is on the road, but pretty much gutted at the moment...I look forward to nicing it up.
> 
> If I may ask, who's "we"? Are you a shop? Just someone with a garage?


Thanks a bunch! I'm just a car guy with an AV company who happens to have a warehouse, so I put a two-post lift in for the project We do a lot of custom rigging work in commercial AV projects, so one of my main guys is good with a welder and we've got some decent tools. I just brought my car home TODAY for the first time, so that is a huge milestone. This thread is about a month old, so over the weekend I will get it caught up. You might appreciate the rest of the custom gauges story. There's still more work to be done with a few bugs, but it sure is a pleasure to drive with that dash in there!


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## jetdexter (May 30, 2018)

More progress:

First, the 12v power steering pump is fed from a BMW/Mini reservoir which we had in a temporary location in the HVAC intake. I needed to test the system before cutting into the car for a permanent location. So this week we moved it to a very odd location above the hood latch mechanism. It is the only place we could put it where the hose can feed at a pretty steep angle downward, which is required for this system. It looks clean and is nicely serviceable.











I also installed all 4 door panels since they'd been dyed black. The wood is still terrible, but that is put off for 6-12 months. I picked up a cheap set of door speakers to fill the holes. All-in-all it looks buttoned up which is all I can ask for for now. I can't wait to have some custom leather panels done next year.











Most most fun I had was with the front bumper. I am using the rubberless older bumper in the rear. I wanted to try to match that up front, so I am playing with this concept. If I like it we will weld and smooth it then re chrome it. So far I think it looks good. Most people seem to prefer no bumper up there, but I like the chrome too much 










Still working towards buttoning the car up enough to present it to my wife in a month or so. Need to get the dash fully put back together and some carpet in. Just about there!


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## jetdexter (May 30, 2018)

More progress:

Brett got the carpet in which makes the car feel totally complete when you sit inside. Padding went down first:











Then black backless carpet:












Then it suddenly became a very finished car:










Yesterday I got the very dusty seats bolted back in:











We got more great progress on the digital display in the Tach position. The new high resolution round display is now starting up with our little animation splash shown here, before it settles into the data display. It looks cooler in animation, but I'm too lazy to post the video to YouTube just to share it here. I will once the cluster is installed next week. Jeff did an amazing job coding this thing up.












And lastly, I got a stepper motor installed into the fuel gauge housing. We are now reading Tesla Battery charge % on the gauge (well not in this photo as we just turned off the ignition, but you get the idea). The last one to do is Temp gauge.










I dropped off my pair of clocks at North Hollywood Speedometer for a rebuild. They will also repaint my MPH needle to white as it is currently an ivory color where the other needles in this car are white.

Once I get that clock back I can reassemble the entire cluster and put it in for hopefully the last time. Actually, I haven't resolved illumination yet, so it will come apart once more for that. There is no space for the old lamp style illumination, so I am thinking of very thin LED strips stuck to the wall of the cans. But I am putting that off for now.

Cheers,

Paul


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## jetdexter (May 30, 2018)

More progress on the coupe this week. Mostly working on getting the instrument cluster assembled for the final time. 

Got the odometer driver board wired up and installed into its housing complete with logo




















Got the fuel (battery charge/range) and temp (most critical temp reading) gauges all wired up and installed into the housing. Here’s a fun little loop:











Up until this point you’ve seen nothing but messy wiring for all my testing. But I’m finally to the point of creating clean wire harnesses. Disconnects on each device end:











Monday I should receive my rebuilt clock and a repainted MPH needle from North Hollywood Speedo. Then I can get the cluster fully assembled and functional!

Finally Tyler got my front fuse/relay box installed under the hood. I will have one in the footwell and the trunk as well, but this one will serve water pump, cooling fans, headlights, horns, and such. All “up front” things.




















Got my license plate lamps installed. There was a time I thought I would never have a shot as clean as this











Got a bit more bright work installed, making the coupe a bit more inviting to step into:











I finally received this beauty in the mail. I can’t wait to get it installed:











Things are coming along!

Paul


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## jetdexter (May 30, 2018)

Still catching up this thread. Here's progress from a week later:

Today I got the instrument cluster fully assembled. I've been sharing bits and pieces of this for a long time now, but it's so great to see it all come together. Two years ago when I started up the project I dreamed up this digital display in the (not needed) tach position, then digitally controlled gauges for the speedo, temp and fuel gauges. Only with the help of talented friends bringing my mockup to life on the display and another friend helping with the analog gauge control could it have ever happened.

What's better is that it's all working in real life in the car. I'm headed out of town today for business but next week I'll be installing this into my new leather dash and taking her for a spin.

I look forward to new wood in the future, but for now I got it polished up nice enough. I was suprised how well the chrome came back- I thought it was corroded completely through. North Hollywood Speedo rebuilt my clock. Crazy thing is that they installed the face UPSIDE DOWN. I was so upset when I went to put it in. And it was the last thing holding me up from completing this. I wasn't about to open it up to fix it, or send it back to them to fix, so I shaved off enough of the mounting tab to allow the mounts to function that way.

I also tried a little trick to bring back the black in the surrounds. Mine were not only faded but discolored and splotchy. I didn't want to remove them to properly paint them (until I redo my wood) so I sprayed black satin spray paint on my rubber-gloved finger and wiped it into the surround. This did a nice job of bringing back just enough brightness in the black and getting into the crevices. 

Here's a little video of the full startup animation:






Anyway, I'm a little proud of the results as you can tell. Not bad for a total hack like me.


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## jetdexter (May 30, 2018)

I am perpetually two weeks away from bringing this car home. Still, more progress has been made this week!

I got so frustrated constantly adjusting the interesting but overly finicky hood latches. So I decided to mod them into a basic modern latch- using BMW E60 latches.










First, Tyler whipped up a couple of adjustable mounting plates.




















Then we could mount the new latches to the car's original mounts.











Then we had to extend the catches to reach into the deeper latch. (Not shown, but we had to extend them further towards the cabin as well).

Finally, we added a pair of springs, then:






This, in combination of our gas struts makes the E9 hood completely non-original but extremely enjoyable to use.

In other news, We got a simple 12v battery disconnect installed into the trunk. My battery is a little motorcycle battery which only needs to activate a relay turning on the Tesla batteries. Since my clock and at least one small computer will be running on the battery when parked, I wanted an easy disconnect both for safety reasons when working on the car but also to disconnect if I am going to not drive it for a couple of weeks. This trunk panel will be carpeted.











Lastly, I am reworking all of my temporary wiring with nice permanent wiring. Three fuse/relay boxes: One in the trunk near the battery which feeds the many Tesla items back there. One in the cabin footwell which feeds items there, then one up front which feeds radiator pump/fans, headlights, horn. One would have done it, but this distributed system seemed to make sense to me, and it seems simpler to work on/add to in the future.












This week I got the front two completely done and clean. The trunk is the most complex and that's next week.

Then I can get back to putting the dash back together, carpet the trunk and bring the car home. That's if I don't find any more "must have" projects like these hood latches

Cheers!

Paul


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## jetdexter (May 30, 2018)

This was a great week of progress and the car is back to Operational status! The last several weeks I'd been working on these schematics. The first 3 sheets are the 12v systems and the last is the HV Tesla system. This represents everything in the car today. Not represented are power windows, stereo, electric sunroof and HVAC all of which will be implemented after I drive the car for a while. (Yes, it's low resolution because they aren't yet complete and I don't want to be blamed for helping blow someone's car up











First I finished up that front fuse/relay box which turned out very nice. The lines run along our battery box. Feeds our headlights, horns, coolant pump, radiator fans. Turn signals pass through here as well so it's all in the same wire loom.






























Then I moved to the cabin footwell fuse/relay box. No photos of that one since it's not fully mounted yet. The wiring is all done in there though. This box has the turn signal relay, a VW "convenience" relay (for 3 flash lane change function) and fuses for the dash and console items.

THEN I moved to the trunk which was a huge project. Here is the "Before" photo. This was the temporary wiring as I was installing and testing each of the various systems. Now that they are all working and refined, I am ripping all the wiring out to start over.











To the right is myTesla DC/DC converter. It takes the 320 volts of Tesla batteries and turns it into 12v to power all our auto systems. I am feeding a pair of 100 amp mega fuses. One of them runs directly to the BMW/Mini electric power steering pump (this is the same fuse as they use in the Mini). The other 100A fuse feeds our three distributed fuse/relay boxes.










My motorcycle battery passes through a cutoff switch before entering the system. This switch will be accessible above the carpeted trunk floor. Since my clock and Raspberry Pi computer will always be running, I will disconnect if I am not driving the car for 10 days or so of if I am working on the car. Otherwise, all the battery does is run through the ignition switch which then activates the DC/DC transformer which charges the battery back up.










Then I wired up my parking brake controller (since the Tesla has no "Park" function, and hand brakes don't typically lock the wheels, so I am using the same Brembo electric parking brakes that Tesla (and many other cars) use. When I put the shifter in park, the parking brakes activate automatically.

Then my 057 Tesla control box got wired up. Everything was loomed nicely and it is all tested and stable.

Notice that Brett is now making a little wire path tunnel on the upper level preparing to carpet that section.











Here's our false floor, which is getting carpet this weekend. A vertical panel hiding the upper batteries is also going in.










Finally I moved to the console. I had been frustrated with the stock mounts for the console as I've had it in and out these last 6 months. Like the dash of these cars, they didn't make it fun to take in and out (which to be fair, shouldn't need to happen a lot). But I figured I might need to be in here a few more times (for one thing, I want to wrap it in leather next year). But I also needed a platform to install my computers. So I did this custom bracket method, which allows for very easy assembly and removal. It just won't win any points with BMW Classic.

First, a couple of angle brackets which can easily be screwed in, unlike the ones that went downward.










Then I cut a piece of wood and painted black. I figured that BMW would appreciate the plywood for originality sake.










Then I began to wire up the computers and the shifter. Molex connectors allow for disconnecting and removing the shifter and all computers. There's the Rasberry Pi which runs the digital display, then a small Arduino computer for Speedo, temp and fuel, then a smaller computer for Odometer.










Next I peeled off the Audi emblem from the shifter and designed a CSE emblem for its place. For $26 an epoxy "domed" sticker printed on foil is already on its way. The cheapest part of the whole car. I can't wait to pop that on there. I do I fear it will take a few revisions of that to get the exact fit just right.










Wiring is done, though not fully dressed. Got the HVAC face in (thought it's just a dummy for now). I don't know how I will approach that in the end. My first plan was to use a 1"tall x 8" wide touchscreen for HVAC, seat heaters and password for Valet mode- but I've gone all soft now to the classic, so I may leave the original controls in.










Which leads me to this: My original mockup (on bmwcse.com) showed an Apple CarPlay unit, but I don't think I want to take it that far. I picked up this vintage Blaupunkt unit and I'll finish a piece of wood to install it into. That will give me a small tray between the shifter and the stereo face. I'll eventually add an Aux in to it so I can connect with bluetooth.










Next week we should have trunk carpet, new windshield, dash and instrument cluster, and lower dash sections all in. And I'll hotwire a basic sunroof switch so that I can open and close it for my drives. I'm finally LESS than 2 weeks from bringing her home!

So that's it for this week's progress. It's been 5-6 weeks since I've driven her but next week I'll stretch her legs out. Meanwhile she's still nice just to look at. And there's my buddy's E9 which is currently getting trunk floors and weeks away from Tesla batteries wiring up and spinning those wheels with watts!

Cheers,

Paul


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## jetdexter (May 30, 2018)

Another good week of progress for the CSE! It is officially coming home next Thursday! Well, that is if our drives and testing continue to go well. Here's what I got done this week:

First, Brett handled the carpeting in the trunk. He shaped a piece of plywood to hide the Tesla modules on the upper shelf. Then he carpeted the whole place. I know it's not original, but it creates a nice clean and very usable trunk for this daily driver. Notice the tabs for lifting the lower section for access to the wiring and such below (no spare tire here). The 12V disconnect is peeking through as well. 











Tyler went back to his crafting table and whipped up this beautiful box for our charging port. I will rework this in the future so that the wire exits the bottom rather than so far into the trunk as it does now. Also, for now I am using a 110/15a slow charger until I get my Tesla charger programmed up.




















We then painted it to give it the stealth look...











...And the car took its first charge through the proper connector. 











I went back to work on the console. I cut a piece of mahogany for our stereo. Since our computers are on the shelf behind I had to design a bit of a hybrid approach to the console where I don't use the non-AC parcel shelf running under the stereo. I have a small "phone tray" section which covers the wiring between the shifter and the computers. 











I then cut in the Blaupunkt unit. This wood is not yet fully stained in this shot. 

The real point of this shot was to show the CSE emblem on the shifter. I am especially proud of this. I measured the Audi Sport emblem and had a company print an epoxy raised sticker on foil with my logo, to my shape. It isn't perfect but it is much better than looking at the Audi logo.











Then Tyler and I pulled the cracked old windshield out and swapped for my new clean glass.




















The dash got put back together and things are looking very suitable inside. I did get my horn connected. 











Now that the car was all back together it was time to take her for a drive. It had been six weeks or more since my last drive. She'd been so "couped" up that she really wanted to run free.











Apparently I couldn't contain my enthusiasm.











I took a couple of photos before putting her away for the weekend. Notice I am halfway done swapping the headlights out for Hella Halogens. I wasn't going to bother and I liked the old lights. But a connector was broken on one of the low beams so I had to replace it with something, so I went this route.











I'm still on the fence about my 17" wheels. I love the grip with all the power i've got, but I keep watching listings for 16" sets and will probably pick some up at some point to at least try them on the car before settling one way or the other.











So it's been a great week. Next week is just a few last things on my list. I've got to get an alignment as the front end is completely custom and we just set it where it looks pretty straight I've got to do a bit more moulding work. I'm going to wire up the sunroof, get my windshield wipers on and such. Every day next week I will drive it further and further with a follow-car so that I can get back to the amount of comfort I had with its reliability before ripping out all the temporary wiring these last several weeks.

Cheers!

Paul


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## jetdexter (May 30, 2018)

I finally drove the car home! After 26 months in the shop it was the greatest feeling of accomplishment that I've ever felt (other than marrying out of my league).
























In case you forgot exactly how far this car has come:

In July of 2018 I bought what my ignorance thought was a decent car. Fair interior, fair steel with some known rust here and there. $11,000 because it was barely running with no clutch and the owner didn't want to fix things up to maximize the value. In the end I learned that $100 would have been too much for this car. Had I paid $40k for a better car I could have put $10k or so in my pocket

The car had apparently been stored underwater when not in use. I have since seen just a few cars with more rust. My media blaster even stopped blasting early because he was afraid that the car wouldn't hold itself up. He was upset with the project and drove it back angry. I didn't really understand this at the time, since his job was just to blast- I wasn't asking him to repair the steel...

Since Brett and I were only prepared for basic bodywork we were left not knowing _what_ we could do with this car. I considered dumping it and buying a painted and ready to go shell that Coupe King had for $40k or so. But since they didn't actually _do_ the work or _see it done_ in this case, and couldn't prove that there wasn't rebar and Bondo galore, I didn't feel comfortable enough - not after what I'd seen could be covered up. I called a couple of metal guys on Craigslist, which led me to Tyler who's become a good friend. Working at a respected shop he had properly restored metal for countless Porsches for check-writing clients such as Seinfeld. Tyler gave me a rate I stomach to come to my shop with some tools and start cutting out rusty bits and fabricating in new ones.

_This is some of the stuff we saw:_

Rebar and fiberglass holding together the inner fenders/strut towers.











Swiss Cheese like this on just about every single panel you could imagine. This thread has photos of so many of the custom fabricated new pieces that Tyler replaced with.











Frame Rails that looked like this.











Sunroof that looked like this from inside- which required 2 months of fabricating from scratch an all new frame and a new top opening.

































Then we put a Tesla Motor and a Battery Box in:






















And for the last year I've been dealing with Brakes, Steering, Suspension, Interior, etc. All so that I could begin to enjoy this car on a daily basis.

If you've followed this thread you know that I am holding off of paint for 6-12 months because I still have to engineer and fabricate air conditioning and much more. I also still need to implement my BMS, 220v charging (currently I am *slow and careful* manually monitored charging, and other Tesla bits. We continue to weld to this car almost every day. Friday we welded a stud on for my hood release handle. We can't afford to damage our paint with all this fabrication to still commence. Every time we weld now, we grab the green primer and fog it in!

For months I have been saying that I am 2 weeks away from bringing this car home. But this time it finally happened. Friday afternoon the car left the shop under Tesla power and drove into my garage. It looks comfortable in its new home while receiving a midnight snack.












I've got a buddy who's a globe-trotting nature and commercial photographer (you can tell how serious he is by the beard and tattoos). He came down and we took some photos and video of the car in Laguna Beach. The photo session was fun, but the drive was FANTASTIC. (And the pilot car was my buddy in his Alfa, so it was a great time for all)






















So while there are still _many_ projects to do on this car, this closes the chapter on a 2 year long story of creating a reliable daily driving Tesla-powered E9. I'll take the kids to school in it tomorrow morning then go to the office where I will spend most of my time daydreaming of how the AC will function.

Cheers,

Paul


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## Tremelune (Dec 8, 2009)

Wow. That's pretty bad. I've been burned pretty hard like that, but I ate it and sold the car. I didn't have the heart to put more money into it! Now you can say you really rescued this thing, and it has a new—almost futuristic—lease on life, with the hot body of a true classic. Good stuff. I love that muted green, but it'll look great in orange too. I'd go with Porsche Tangerine, personally...


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## jetdexter (May 30, 2018)

Tremelune said:


> Wow. That's pretty bad. I've been burned pretty hard like that, but I ate it and sold the car. I didn't have the heart to put more money into it! Now you can say you really rescued this thing, and it has a new—almost futuristic—lease on life, with the hot body of a true classic. Good stuff. I love that muted green, but it'll look great in orange too. I'd go with Porsche Tangerine, personally...


Thanks for that! And Porsche Tangerine is about my favorite all-time color, and about what I was thinking. I like it better than the brighter orange BMW used for these (Inka).


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## jetdexter (May 30, 2018)

Here's a little video my photographer buddy made for the car. I call it the "BMW CSE Lifestyle" video


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