leigerreign New Reader
Dec. 7, 2009 9:10 p.m.

So ive decided I want to make an E-VR4. Yes a 3000GT VR-4 electric vehicle. I want it to retain its 4WS, AWD, and track manners.

I also want to lighten it up as much as possible. Not stripped, but on a nice diet. Most of the weight in that car is up front....so by deleting the engine and tranny....id shave about 900lbs there.....plus no exhaust, gas tank, etc....

Unfortunately, i would be adding hefty batteries and electric motors.

My idea was to measure the center of gravity (front to back) on the car and place the electric motors in the driveshaft tunnel (sticking into the car) at that point. Machine flanges for the motor shafts that mate to pieces of the stock 3 piece driveshaft and put power thru the stock rear end.

For up front, I want to take another rear end differential and mate it to the stock CV boots by machining flanges for the rear end that would snap in the stock CVs and bolt to the stock axle flange on the differential. Plus, i would locate the differential in the stock location of the stock front diff so all steering geometry is maintained.

As for the other stuff (AC, PS pump, heater core water). I will use a 1HP electric motor to run these and the diesel generator is water cooled so if heat is ever needed it can be supplied from that.

Speaking of that, I intend to place a DC diesel generator up front for long distance trips that would be capable of fully supporting the cars electrical needs on highway trips. It would be removable for daily commutes tho (engine hoist it in and out when needed)

Looking good so far?

As for my questions....im torn between using an AC or DC motors. AC is more efficient and lighter but it comes with the added expense of a 24VDC to 240VAC inverter which just really sucks.

Also, i want to do this on a budget. Where should i look for used motors and generators? Im located in Ormond Beach, FL...right next to GRM headquaters. Are there auctions i should be attending or something better?

Thanks guys!

MrJoshua SuperDork
Dec. 7, 2009 9:51 p.m.

http://www.diyelectriccar.com/

(no method is cheap)

erohslc Reader
Dec. 7, 2009 10:12 p.m.

Rather than mount/demount the Diesel Generator set, why not put it on a small trailer? That way, for long trips, you just hook it up, and go! Will give you a lot more room for batteries, extending your 'around town' range between charges.

Carter

Vigo New Reader
Dec. 7, 2009 11:31 p.m.

I am intending to attempt a much less ambitious electric propulstion system on my 1990 caravan.

Even starting with much less complex ideas than yours, it still seems like a pretty steep learning curve, and expensive as far as parts. I hope that i set a goal i can hit.

kreb Dork
Dec. 7, 2009 11:54 p.m.

Wow, you're biting off a hell of a big piece. FWIW I think that the 3000GT's a poor choice due to it's heavy weight. Not to be a drag, but you're better off starting with an old Honda and going the conventional route. Then, if you want to try something real involved, do so at that point.

VanillaSky Reader
Dec. 8, 2009 12:15 a.m.

Can I help?

Dec. 8, 2009 6:06 a.m.

this is not a sports car but hopefully it will still give you some inspiration. This is being done by a guy on gasp another forum I visit . Hes a pretty smart guy, and hes doing this in spare time with spare money since hes in college. Its pretty motivating...

tuna55 Reader
Dec. 8, 2009 6:43 a.m.

Sounds like a great Volt-esque plan. I'd love to see it come to fruition. Make the generator removable for track days or something...

DeadSkunk New Reader
Dec. 8, 2009 10:36 a.m.

Google "electric drag racing" and you'll find a whole new world of stuff.

Nashco
Nashco SuperDork
Dec. 8, 2009 11:57 a.m.

As mentioned, that's a seriously heavy car to be trying to make a sporty EV with, especially if you think you can do it on a budget. If you're really set on AWD, perhaps consider a lighter chassis like an Impreza or Civic; with a chassis that light, you can use a single motor mated to the stock manual trans and use all of the stock axles, trans, mounts, etc making this a MUCH easier/cheaper/realistic project. Heck, I bet there's even off-the-shelf adapters out there for the Honda. As mentioned above, get on the diyelectriccar.com forums and start reading, you've got a lot of learning to do. It's a very steep learning curve and you need to run some basic performance calcs to see what you'll need for motors, batteries, vehicle weight, etc. to balance your performance goals and budget limitations.

Bryce

Toyman01 HalfDork
Dec. 8, 2009 12:55 p.m.

Building a EV is something I always wanted to do, but could never afford. A few things you might consider:

Most ev conversions run through the stock transmission because they need the gear reduction just like a gas engine.

Most automotive AC compressors take 5-25 hp to run. You would be better off changeing to a more electric friendly system. PS pumps are going to have a similar problem. 1hp just isn't going to get the job done.

The diesel generator is going to be rather large. A 6kw system just isn't going to supply enough power. If it takes say 25hp to push the car at highway speeds, by the time you figure losses, the gen set is going to need to be in the 30-35hp range which converts to 22-26kw. That is a honking big generator that probably won't fit under the hood.

Having never built an ev I migh be way off base though...

DeadSkunk New Reader
Dec. 8, 2009 3:55 p.m.

If you run a stock trans, I'd think you'll need to change both differentials to get a lower (numerical) ratio. I don't think electric motors are available in the same RPM range as a stock gas engine.

Nashco
Nashco SuperDork
Dec. 8, 2009 4:01 p.m.
DeadSkunk wrote: If you run a stock trans, I'd think you'll need to change both differentials to get a lower (numerical) ratio. I don't think electric motors are available in the same RPM range as a stock gas engine.

???

Your average DC brush motor turns similar speeds to a gas engine, just has a different torque curve. Most applications find that second-fourth gears on a typical 5 speed are the only useful ones, usually just picking either 2nd or 3rd when they take off from a stop based on the drive cycle they expect. For performance driving with a cheap DC motor, you'd probably want to use a clutch and be able to shift as necessary. You DEFINITELY won't need any different differentials.

Bryce

leigerreign New Reader
Dec. 8, 2009 4:16 p.m.

You guys are awesome. Thanks so much for the advice and guidance. Ive been doing alot of research and it seems a few small tweaks here and there should be sufficient.

I like the trailered generator idea....but i want to retain the sporty look of the car, so if possible ill fit a generator under the hood.

I could definitely use the stock trans but i was hoping id be eliminating weight by just running two differentials....seeing as the torque curves work out well for my stock rear end gear ratio. Plus, if i use the stock trans then i cant do the under-hood removable generator idea.

Hmmm.....so much research to do. I really want to build this.

MrJoshua SuperDork
Dec. 8, 2009 5:08 p.m.

You can do it but you need a good controller and lots of good batteries. The motors are not the hardest part. A couple of refurbished GE 9" motors with the timing advanced can provide a great deal of propulsion.

Look up "Joule Injected". It is a 240sx powered by a direct drive (no transmission) siamese 9" motor setup, 25 Optima Yellowtops, and a Zilla 2k AMP controller. That setup delivered a 13 second 1/4 mile time on street tires. The dyno showed 600ft lbs of torque and 150hp. Your AWD setup will somewhat make up for the fact that you are carrying more weight.
To be quick you need lots of good batteries, motors that handle high amps, and a really high quality controller. You are looking at the Zilla, Soliton, or soon to be released Netgain line of controllers if you want any zip.

AC seems like it would be better, but very few high power systems are actually available or available at any reasonable price (sub $10k). There is a system using a Curtis controller that is semi reasonably priced, but it is still fairly low power. The only way I would currently suggest AC was If you could find a system like Nascho snagged and use 2.

Soon Netgain is releasing the 11"HV motor. This motor is claimed to be designed in a way that allows it to handle the typical high amps (torque) of current performance DC motors, while handling the high voltage required to carry that torque into high rpms. They are also built to stay together at high rpms (a current weakness of your average DC motor). That motor with a good controller and a powerglide behind it would be a great performer.

DeadSkunk Reader
Dec. 8, 2009 8:41 p.m.

Nashco, Are there DC motors that can go to 6 or 7 thousand RPM in a car useful size? Most of my experience was with DC pump drives that were maxxed out at 4500.

MrJoshua SuperDork
Dec. 8, 2009 8:43 p.m.
DeadSkunk wrote: Nashco, Are there DC motors that can go to 6 or 7 thousand RPM in a car useful size? Most of my experience was with DC pump drives that were maxxed out at 4500.

Im not Nashco, but other than a Jim Husted modded motor or the netgain HV, you are pretty much into the red above 5k.

xci_ed6 Reader
Dec. 9, 2009 12:05 a.m.

Lightweight AWD electric calls for 4 separate motors and controllers. Possibly linked by some kind of traction control system.

Nashco
Nashco SuperDork
Dec. 9, 2009 12:46 a.m.
DeadSkunk wrote: Nashco, Are there DC motors that can go to 6 or 7 thousand RPM in a car useful size? Most of my experience was with DC pump drives that were maxxed out at 4500.

No, like Josh said 5k is pretty typical...however, I consider that pretty darn close to gas-burner range when you compare it to my AC motor that does 15k RPM. The gearing is well within useful range when dropping a DC motor onto the original (gas-burner) trans.

Bryce

neon4891 SuperDork
Dec. 9, 2009 12:57 a.m.

here's my $.02

Last time I checked, electric motors have a flat TQ line. Full TQ from idle to red line.

As for driveline, DC should be fine. Most cars I deal with cruise at 1500-2500, and dont go above 5k unless driven hard.

neon4891 SuperDork
Dec. 9, 2009 12:58 a.m.

Great, now I want to try some EV conversion

MrJoshua SuperDork
Dec. 9, 2009 6:01 a.m.
neon4891 wrote: here's my $.02 Last time I checked, electric motors have a flat TQ line. Full TQ from idle to red line. As for driveline, DC should be fine. Most cars I deal with cruise at 1500-2500, and dont go above 5k unless driven hard.

That depends on the controller. If you have a controller with a really low amp limit it is possible to have a motor that behaves that way. Typically what happens is you have high torque at low rpms that falls off as the rpms rise. This is true of both AC and DC. AC can carry the torque higher, but tends to have slightly less to start with. What you are more likely to end with is a flat hp curve.

This link :Crazyhorse Pinto Dyno shows an extreme example of what is possible. Again, it takes LOTS of batteries and 2000 amps to do that.

kb58
kb58 Reader
Dec. 9, 2009 8:18 a.m.

I can't get past the donor platform. Once upon a time I was interested in a 3000GT, but when I learned it weighted, with driver, 4000 frickin pounds I lost interest. Consider starting with something like the Honda Insight (I think that's the name, their first hybrid that was a sales flop.) Much ligher and far, far more aero. (I'm assuming you'd strip out all the existing drivetrain and add your own.)

turboswede SuperDork
Dec. 9, 2009 10:05 a.m.

Here's an interesting take on the AWD EV:

http://dpcars.net/dp1e/info.htm

http://dpcars.net/dp1e/index.htm

Not cheap or very handy on the street though :(

leigerreign New Reader
Dec. 15, 2009 3:21 p.m.

Okay so after much research, ive decided two 3 phase AC motors are the best choice coupled with inverters. Two of these in direct drive will work well, and i found a supplier that offers a 530Nm (peak torque), which is about 390ft lbs, power motor that will fit my size requirements as well, and better yet theyre only 68kg each.

Also, ive discovered through the 3si forum the weights for everything I will be deleting....and after all is deleted the car will weigh 2400LBS!!!!! I think thats huge! I mean, the car is 3800lbs stock. Meaning, that with a direct drive setup and just one cluster of batteries for autocross use.....i could be carving cones at 2800lbs!!! And thats before extreme weight loss procedures! I know that seems heavy for most cars but i think thats a major accomplishment for a 3S.

As for the electric generator idea....im sticking to it. I just need to find somthing within my means. The motors and inverters/controllers themselves are going to be awfully difficult to afford on a college student's budget alone.

So far, this is not really grassroots material.......im looking at about $15k with everything id need (body and interior "upgrades" as well.)

Hopfully i may be able to find somthing more economical. Im still searching.

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