# Convert Mazda FD RX7 twin turbo rotary



## RXHEAVEN (Jun 9, 2008)

I am a newbie to everything EV, just wondering what sort of ballpark $$$ figure would be required to convert a 2000 Mazda RX7 Twin Turbo Rotary to be an electric car.

I would be looking at a range of around 100miles/160km per charge and respectable acceleration. Must be able to do Freeway speeds as well.

I don't even know where to start on this.

Thanks


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## RXHEAVEN (Jun 9, 2008)

I already own the car. Is that cost purely for the EV gear?

Also, surely it can be done a lot cheaper?
What are the chances of 10k-12k ?

Do you generally re-use the factory gear box and driveline?
Can u maintain ABS function etc. 

Cheers


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## RXHEAVEN (Jun 9, 2008)

What battery pack, controller, motor would someone suggest for this project. I do a 25km round trip to work each day, so could even charge it nightly if it were to bring the cost down significantly


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## xrotaryguy (Jul 26, 2007)

Charging it nightly is the standard practice. Actually, in a perfect world we would all be allowed to charge at work too.

I don't know if the Porsche guy added the cost of the kit car into the $60k figure, but even if he did, the conversion cost would sill be $45k or so. The good news right now is that real car range is finally possible with Li ion batteries. The bad news is that Li ion batteries are still very expensive.

Look at that guy's conversion and start pricing out the cost of all of his components. You will get a clearer picture of where the money went pretty quickly. 

BTW, might have guessed from my screen name, I think that your choice of donor vehicle flat out kicks ass.


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## DVR (Apr 10, 2008)

It depend on what you want/expect performance wise. 10-12K is doable but would most likely have disappointing performance compared to the ICE motor. However for that budget you would easily do the 25K round trip to work and have a top speed of maybe 50-60 mph but you will have to use lead acid batteries so it will be a heavy and bulky battery pack. You might have trouble fitting them in an RX7.
Look at KIWIEV's conversion of the TREDIA to get an idea of whats involved and the sort of performance you might get for a similar budget.

The only way you will get 100 miles per charge in a RX7 is to use Lithium batteries and you'll be easily doubling your budget to do that. But they are Smaller, much lighter and last about 5 times longer.

Sorry to be a downer but them's the facts


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## xrotaryguy (Jul 26, 2007)

> It depend on what you want/expect performance wise. 10-12K is doable but would most likely have disappointing performance compared to the ICE motor.


Ever driven a 3rd gen Rx7? This is the understatement of the century.  It took the Corvette about a decade to catch up to the performance of the 3rd gen.

An FD is a fantastic starting point for an EV. The chassis is extremely light. The brakes are certainly up to the task and upgrades are readily available. Suspension upgrades are easy to come by.... the list goes on for ever.

If you're not looking to spend 60k on a car right now, you could always build it to cover about 30 miles (one way, charge at work) at a reasonable speed like 55 mph. Then, at some later date, you could save up for some LiFePo4 batteries and make it fun again.


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## RXHEAVEN (Jun 9, 2008)

really good info so far guys, keep it coming, thanks a lot


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## Zer0 (May 9, 2008)

Fantastic vehicle choice! I have always loved the FD3S, one of the best looking vehicles of all time IMHO. I wish I could own one, but I digress...

To answer some of your earlier questions:
In a basic conversion, you do re-use the factory gearbox and driveline. Most times, an adapter plate is machined so that you can mate the electric motor to the existing transmission. ABS/Airbags/power steering and other functions can be maintained, but require some work-arounds depending on how those systems function (vacuum, hydraulic, electric). A lot of people who have done conversions (not me ...... yet) have found great solutions to these problems. Hopefully one of them can chime in and let you know where to start looking. Otherwise, keep looking at conversions that have already been done and try to get a feel for what you want.

Are you looking more for range/economy with this conversion, or power/performance? Just like ICE engines, these choices make a huge difference in what you want to look at buying. 

I guess a lot of it depends on if you can come down a little on your original range expectation and what you mean by "respectable acceleration". As to the Porsche replica/conversion, I don't want to step on anyone's toes but 0-60 in 10-14 seconds may be great in the EV world, but is painfully slow and unacceptable for most cars. Especially when your donor car was originally capable of 0-60 in 5.4 seconds (if I remember correctly, that is the case for the 3rd gen RX-7?)

If your leaning towards performance, check out what people like John Wayland have done:
White Zombie Electric Drag Car
National Electric Drag Racing Association (NEDRA)


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## VDubber (Jun 2, 2008)

FYI, the worlds fastest street driven electric car is a Mazda RX7:

http://www.dragtimes.com/Mazda-RX-7-Timeslip-7519.html
http://www.evparts.com/galleries_zoom.php?GALLERIESTAG=1l
http://www.evalbum.com/047.html

But it is heavily modified, so maybe that doesn't really count.


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## RXHEAVEN (Jun 9, 2008)

Those drag cars are impressive. The Series 8 FD3S does 0-100km/h in 4.9 or 5.0 seconds in factory trim, depending on where you read the stats. I now realise how hugely expensive it is for a top notch conversion. Looks like waiting for Li Ion to come down is the way to go. I would still be interested in knowing ballpark figure of how much it would cost right now in this point in time to have say only a 40km range and performance of 0-100 in under 8 seconds. I realise the more often you boot it, the quicker the batteries would deplete, so how about a rough guess assuming the following.

40km range
0-100 in 8 seconds capability
80% of journey is just cruising along at 70km/h
5% of journey is pushing it as hard as it will go (full throttle)
15% of the journey is mild acceleration (just normal taking off from green lights) assuming light traffic to/from work etc.


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## VDubber (Jun 2, 2008)

25 mile range at 45MPH, that should be quite doable without LiOn. The great thing about electric is that you can carry around a huge peak HP, while still getting top mileage.

You would be looking at a single 9" or 10" motor, with a Zilla 2K and a higher voltage string of quality AGM batteries (Orbitol yellow tops or Odyssey PC2150/2250 have been proven tough). I would think at least 180V.

You could grab a PFC20 or PFC30 charger from manzanitamicro.com - they will charge up to a 450V pack from a 220 dryer outlet, or a 180V pack from a 110V outlet. You will also want to get a set of M2k regulators (one for each battery) - they will talk to the charger and keep your pack healthy.

One benefit is that the RX7 has minimal frontal area, so your wh per mile can be nice and low. The biggest hurdle will be finding places to stuff the 15 or more batteries.

Let us assume you get it down to 350Wh/mile. This will take some doing, but possible. 350Wh * 25 miles = 875Wh / 180V = 49Ah. Now you will get about 400 cycles at 80% DoD (one-two years), and 800 cycles at 50% DoD (two-four years). So 49Ah / 80% = 61Ah (Orbitols or Odyssey PC2150), and 49Ah / 50% = 98Ah (Buddy-pair the Orbitols or Odyssey PC2250). 

The PC2250 (or two Orbitols) is 86lbs. 15 * 86lbs = 1290lbs(!), or 15 * 60 = 900lbs. Given that those batteries can slam out over 2000A for ten seconds (@ 180V, even with sag that is well over 300HP), you can still have 0-60 in under 8 secs even with that weight. But don't expect to hot rod AND get 25 miles on the same day. And try not to break the stock drivetrain like the Mazda I linked to did...

$2000 - Zilla 2K 
$1600 - Netgain Impulse 9
$900 - Adapter Kit
$6000 - 20Kwh AGM Pack
$2200 - PFC20 Buck Charger
$600 - 15 Mk2 Battery Regulators
$400 - Wiring & Misc Stuff

So you could do it starting at about $13,700.

(I love how people don't think you can get good performance out of lead acid, almost all of the drag racers use it for some reason)

Please see White Zombie's younger sibling, Blue Meanie for an AGM-based daily driver with 0-60 in 6 secs and a 25mile range. He is using only a Zilla 1K, A 9" motor, and a 168V/47Ah pack (about $10K):

http://www.plasmaboyracing.com/bluemeanie.php


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## JRP3 (Mar 7, 2008)

VDubber said:


> (I love how people don't think you can get good performance out of lead acid, almost all of the drag racers use it for some reason)


Exactly, especially if you don't have long range needs, though I'd try to bump up to a Warp11 if you want performance, plus easy performance gains in the future when you can go lithium.


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## DVR (Apr 10, 2008)

VDubber said:


> (I love how people don't think you can get good performance out of lead acid, almost all of the drag racers use it for some reason)





JRP3 said:


> Exactly, especially if you don't have long range needs


His original post asked for 100 mile range.



RXHEAVEN said:


> I would be looking at a range of around 100miles/160km per charge and respectable acceleration. Must be able to do Freeway speeds as well.


Do that with lead? I dont think so.


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## JRP3 (Mar 7, 2008)

DVR said:


> His original post asked for 100 mile range.
> 
> 
> 
> Do that with lead? I dont think so.


Keep reading and you'll see he's significantly reduced his range requirements to 40km, 25 miles. Very easily obtainable with lead.


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## JRP3 (Mar 7, 2008)

VDubber said:


> $2000 - Zilla 2K
> $1600 - Netgain Impulse 9


Where can you get a Zilla 2K for $2000? I think it's more than twice that price.
http://www.cafeelectric.com/shop/index.php?main_page=index&cPath=1

Also, I'd at least go for a Warp 9 over the Impulse 9 if he's looking for performance.
Personally I'd try for a Warp11 and settle for a Zilla 1K, then upgrade the Zilla in the future if you want more performance. The old Zilla will certainly hold it's resale value.


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## DVR (Apr 10, 2008)

JRP3 said:


> Keep reading and you'll see he's significantly reduced his range requirements to 40km, 25 miles.


Read it again and you will see he revised it AFTER we told him whats possible



JRP3 said:


> Very easily obtainable with lead.


Told him that too



DVR said:


> It depend on what you want/expect performance wise. 10-12K is doable ...............
> 
> ................. However for that budget *you would easily do the 25K* round trip to work and have a top speed of maybe 50-60 mph but *you will have to use lead acid batteries* ..................
> 
> ...


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## VDubber (Jun 2, 2008)

JRP3 said:


> Where can you get a Zilla 2K for $2000? I think it's more than twice that price.
> http://www.cafeelectric.com/shop/index.php?main_page=index&cPath=1
> 
> Also, I'd at least go for a Warp 9 over the Impulse 9 if he's looking for performance.
> Personally I'd try for a Warp11 and settle for a Zilla 1K, then upgrade the Zilla in the future if you want more performance. The old Zilla will certainly hold it's resale value.


Ooops, I meant Zilla 1K


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## Manntis (May 22, 2008)

Welcome, fellow rotorhead! (or former rotorhead, since we're both interested in electric RX-7s as well)

I converted an FB using an AC55 motor, DMOC445 controller, and lithium ion batteries. The cost to convert the car was (_assuming prices at the retail rates I was quoted_ to give a worst case scenario) *$28,328* plus labor (welding, etc), shipping, broker's fees, and applicable taxes - not to mention the cost of the car itself.


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## JRP3 (Mar 7, 2008)

Lexus said:


> *Conversion Cost $15,000*


That is one sweeeeet conversion for $15K  Of course that was probably a few years ago since it's number 260 on the EValbum, lead prices alone will drive that price up now, but still pretty nice and a great example of what can be done with lead, especially AGM.


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## EVnewbe (Aug 6, 2008)

If you contact [email protected] and ask for Kelly. 

Kelly had his 944 Turbo Porsche converted to an EV and has been having a wonderful time. Apparently the gas station has not been used for the past three months. He gets 40 miles per charge and uses lead based batteries. For more information contact him. The car looks great and Kelly has a wonderful, powerful ride.

I'm thinking about converting a Fiat for my first EV. The 40 mile range is just right and I can plug in at work for a recharge. The company is really going green and this would be a big plus for them to crow about. Maybe your company is looking for a green project too. You never know until you ask. All I want is the charge at work each day. 

Have fun with your conversion.

EVnewbe


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