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Old 08-01-2015, 10:09 PM   #1 (permalink)
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Adding these electric motors to the back wheels of my FWD gas car?

I have a 2006 Impala SS. It is FWD and I want to add electric drive to the rear wheels. Since it is a big V8 in a FWD car, when you gas it hard, weight goes to the back tires, leaving the front tires without good traction. I'm sure you guys all know about that. Either way, it is a very fast car... once it gets going.

So I would like to put 2 of THESE motors in the back of the car- one on each wheel. This means that one would have to be set up to spin the opposite way, which the site says is possible upon request. They also have single-ended versions. So I'm just posting this here to see just how possible/viable it is to do.

My main concern is whether or not those motors can work together with each other, the gas engine in the front, and the car's transmission. Also, how reversing would work. I'm assuming the electric motor controller would tell them not to work, or to spin backwards, in reverse, but I am not sure.

If you are interested in all the reasons and the end goal, read on. However, most people can probably tell me if this is possible just from the TL;DR/

Here my full on goals and reasons:
My engine has more torque(327lbft) than is practical in a FWD car, but I feel like I can solve that problem, and make my car incredibly fast, by adding these high torque motors to the back wheels. The primary goal is speed, particularly speed during the launch of the car. Once the car is in 2nd gear, I would like the electric motors to just stop, because they probably won't be helping after the car is over 50 mph, which is when the gas engine can really shine like it should.

So, if at all possible, I would like a controller for the rear motors that I can hook up to the car's ECU that I can set up to do that whole "turn off after 2nd gear", or 50mph, thing. I would use this in conjunction with a flash tuner for the actual car engine that would be set up for an open exhaust(courtesy of an electric cut-out, allowing me to go back and forth between stock exhaust and pretty much straight pipe) and all out speed. I would get this tune custom made by some pros at a dyno after the electric motors were installed.

For this idea, I would like to use the flash tuner to force the car to stay in 4-cylinder mode(it has active fuel management already) and rev limit the 4 cylinder engine to 2200 rpm, which is how it is already limited. Trying to go above 2200 rpm in 4-cylinder mode will just re-enable 8 cylinder mode. Then I would use the electric motor controller to only enable the electric motors after the throttle is pushed beyond a certain threshold, like maybe 40%. The idea is that the electric motors will only help the 4-cylinder engine in acceleration BEYOND what 2200 rpm would allow. So I would find out the throttle % for 2200 rpm in 4 cylinder mode(lets say its 34%) and then I would tell the electric motor controller not to engage until the throttle is at 40%, giving me a little leeway before the electric motor kicks in when im cruising. I understand that I would probably have to then have the electric motors start at whatever ampage is necessary to accelerate the car organically at whatever speed I am going, which may be difficult unless the controller can have a different setting for each individual gear that the transmission is in.

Loose ends
I would like to have a decently sized battery, with maybe 20-30 miles or so of hybrid range, that I can charge up with power from the grid, allowing me to do all of this without having to load the engine, thus avoiding the whole "mechanical into electric back into mechanical" loop that would just make my economy even worse.

If the battery, which I assume will be in the trunk, ends up getting too hot, I will probably go with water cooling routed to a radiator in a wheel well(or both wheel wells, for double the cooling), assuming I find out that there is sufficient air speed in the wheel wells.. If not, then I'll suck it up and make a legit radiator in the front of the car for it.

I would also like to load the wheels on command, if possible, using a switch in the cabin or something. This way, if I had used all of my battery, but I wanna off my car's totally awesome launch ability, I could just drive around with the wheels loaded and charge the battery enough for a launch. Or, if I knew I was about to coast to a complete stop down a hill, which actually happens a lot for me, I could just flip the switch and get a little juice back. I am just assuming that automating this would be a little more difficult than is worth it, but I would like to have the feature.

Finally, the car needs to be able to go back to basically operating like stock at any time.

Speed mode: Open exhaust, super fast tune, electric motors on full blast from launch(or as much power as I can without them peeling tires), and then electric motors shut off at a certain MPH or gear.

Eco Mode: 4 cylinders, 2200 rpm limit, electric motors only for acceleration.

Stock mode: Obvious

Extras: A switch to operate the loading mechanism to recharge the battery. It would look nice next to the switch that would open/close my exhaust cut out.

SO, am I naive and foolish, or is this a viable project that I should spend my time/money on? Basically, if it is not too hard, I want to do it. As long as it doesn't cost more than ~$5k, money won't be the issue. Right now, I just need to know if it can work the way it does in my dreams.


Last edited by ciano22; 08-01-2015 at 10:17 PM..
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