Building an electric RX-8, need help.
 

Hy guys.

I'm working on an electric car. It should be one of (or the) fastest electric cars on the planet. The power will be over 350kW.

First I wanted to build my components in my 1988 BMW 3-series but I wanted some more attractive car. The RX-8 looks like a perfect donor but I would first like to know some stuff before buying it. I hope that you can help me...

1. How much space is available when the motor and transmission is removed? Photos would help a lot...

2. The weight of the car without motor and trans?

3. How much power and torque can the RX-8 diff take? Are there some stronger after-market diffs available?

4. Any other problems with the car that I should be aware of?

I'm very familiar with European cars but not with Japanese one...

Here's a drawing of the motor that I will use:

http://img5.imageshack.us/img5/8367/11inchmotor.jpg

Two of them will be bolted together. They will use the same shaft that will be bolt on the cardan (the shaft that's usually between the gearbox and the diff, I'm not sure if that's the english word for it :uhh:).

Can two of them fit under the hood or even in the gearbox tunnel?

One motor is 70 kilo's. The batteries will be in the trunk - 350 kilo's.

I hope that you can answer a few of mine questions :)

Sorry for my bad english

Cheers :beer05:

Sorry to inform you, but there is already an RX-8 with power OVER 9000

^Um what?

https://www.rx8club.com/rx-8-racing-25/weight-stock-rx8-parts-81791/

The weight of stock RX-8 parts

The power level....IT'S OVER 9000!

Not my AT! *sobs*

I'm right there with you pal. :tear:

I don't think the car will be able to turn or brake with 350KG mounted high behind the rear axle?

^Yes. One of the reasons the 8 is so quick is its 50/50 weight distribution. Having 2 70kg in the engine bay and 350kg weight in the back seems like that will throw it off quite a bit.

OP what are your intentions for the car? Drag?

To help the environment. It's called going green or some nonsense.

BS, electric cars don't help the environment, they just require more coal to be burned.

At this point the only truly eco-friendly cars are hybrids and super-efficient gas/diesel cars, they're the only ones that really do something to reduce CO2 emissions. Electric cars won't be clean until we find a way to produce the majority of electricity cleanly, and we're nowhere close to that at this point.

with out getting into nano tech or the work ive done in the past.........


2 words.... solar power. no coal needed. Also -- No coal ever... natural gas is better for power plants

Well power plants are more efficient at converting fossil fuel into electricity from the chemical reaction. That doesn't mean I approve of electric cars because batteries will always remain crap compared to a true fuel source.

See, imo, saying that electric cars will require more coal to burn is silly. I think our power grid is so out dated it isn't even funny. If we had a proper nuclear power grid in this country we could eliminate all the coal power plants. Coal is so outdated it isn't even funny. Electric cars pollute none (besides the disposal of their batteries, I guess, or potential accidents). Its only the shitty form of power generation we use (coal), that causes pollution. Get rid of coal, and upgrade the shit out of our powergrid, and voila we can produce ample clean energy.

And don't tell me its unreasonably expensive to upgrade our powergrid..

Even if 10% of the $2 trillion that constitutes just last years deficit was used to upgrade our power grid a lot would change. But nooo..we spend money on such shit and so foolishly it isn't even funny.

I love how no one has answerd any of his questions

I agree with Star Mazda and Ross_Dawg with the weight distribution thing. Maybe by placing some batteries up front and some in the back? With all the parts not needed for an electric motor (radiator, alternator, water pump,...) surely some space would be available in front.

I wouldn't want to keep the heat-producing engine right next to the batteries.

I ripped off my BMW, his weight was 700 kilos. I estimate that he would have around 1250 kilos with all the electric components inside.

The electric motors won't produce as much heat as ICE's so the heat won't be a problem at all. I can put as many batteries in the front as I want to get a 50/50 weight distribution.

About the pollution... It's not truth that plug-in electric cars are more polluting than ICE's. Even if the electric energy is entirely produced of coal the electric car is 40% less polluting than an ICE powered car (EV's have an efficiency of 90%, standard cars around 20-30%). In my country (I'm from Croatia) the most power is produced by hydro power plants. Besides that, my company is dealing with renawable energy (wind farms, bio-mass ect.). I'm producing more energy than I can ever burn in a car... So don't worry about pollution :)

98% of the batteries can be recycled (lithium batteries). The lead-acid batteries are out dated, no car producer will ever use those to power a car.

I know all that stuff about electric cars, pollution ect. I didn't came here to talk about that...

If someone is interested in EV's, visit this page...

http://www.diyelectriccar.com/wiki/

P.S. Can someone answer my questions, please? :)

Not sure on actual dimensions, but it looks like your coupled motors are only 36". Should be plenty of space when removing the mill and tranny.

The curb weight of my '06 is listed at 3075 lbs. The weight of the motor and tranny is ~270 lbs. By some quick figures, I come up with around 1200 kilos.

No idea on this one.

After spending time on here, looks like most problems are engine or ECU related. Since you will be getting rid of those....

We call it a drive shaft (or propeller shaft if you prefer). Its carbon fiber on the RX8. Not sure what kind of torque they will take, and using a DC motor, you have a LOT of torque available pretty quickly.

Should be able to, yes. See above.

around 308 lbs for the motors (plus mounting hardware). With the batteries, she's gonna be tail heavy as an old RX7.. :). You will probably need to upgrade the suspension to something a little heavier.

I hope that I was able to answer some of your questions! And your english (american) is spot on. :)

I'm an industrial electrician, and I'd like to know how your project turns out.

Tchuss!

Thank you a lot!

I will post my progress here when I start to build the car.

Some pics of the engine space and gearbox tunnel would be great :)

I'll break out the digital camera and see what I can do about a few pics under the hood. I don't have the capabilities to bring it up on a lift, so the transmission tunnel will pose a few problems.

I've read on the boards here about some high-power engine swaps, and believe that the car's carbon fiber drive shaft should be fine to around 500 horsepower, and the standard differential should be fine up to 650+ horsepower. I have no idea how many kilowatts that is.

I'd imagine the torque value would be more important, as electric engines are more prominent in that factor.

There is one problem that you will run into doing the conversion. The steering rack is electrical assist. I don't know that this is going to operate without the PCM. You would be removing that when gutting the engine bay. You may have to fabricate a steering rack, steering shaft and associated goodies. The automatic transmission, I believe, also communicates with the PCM.