My (very) hypothetical, probably bad, idea

I have a perfectly good FWD sports coupe. It has beautiful lines, handles well, fantastic V6 engine. Just about everything I could want.

Except that's not quite the case, I want two more things. One of those is a hybrid, one that can spend most of its time driving around town on the electric motor(s) and only run the gas engine when needed (road trips, etc.) (Chevy Volts work like this.)

The other thing I want is a RWD sports coupe. Something that is basically exactly what I have, only driving the other set of wheels.

Gears are turning, in my brain...

What (other than time, money & skill of course) would be stopping me from combining all three of these things? Put a full battery-electric drive in the boot, powering two big motors at each rear wheel, along with some kind of low-drag disconnect clutch on the front axles. Use the electric drive in RWD mode for day to day commuting and the gas engine in FWD for long trips where electric would run out of range. It could work!

If you guys were gonna build something like this, how would you do it?

I wouldn't even need any seamless changeover, pulling over & starting the other engine would be fine. The only major complication I can see is running the power steering pump when the gas engine is off.

Why doesn't somebody make a kit to do this?? :P

Whoops, I just saw HungaryBill's thread. This could probably have gone fine in there.

Except ... I'm not drunk. :P

Electric power steering? And didn't someone kinda do that already with a fiero?

You could use an electric power steering pump. No reason the idea can't work, you could use a whole Leaf powertrain and part of a Leaf battery pack. The hardest part might be converting the rear suspension to a driven setup.

What about a series hybrid configuration, where the gas engine simply drives a generator to charge the battery pack?

Doesn't McLaren's super car already do this?

Supposedly one of the new Prius models is/was going to be available with a separate motor and drive train for the rear end to make it partially awd. The whole works out of the back might be the easy button.

It could work, but...

On the scope front, you'd be completely reworking the back of the car. New uprights to start with, because you need ones with holes for driveshafts, bearings, etc. Unless your car was available with AWD, that means you're probably fabricating an entirely new rear suspension. Preserving the existing handling of the car while doing this is going to be hard.

You're going to be cutting most of the trunk floor out and fabricating a new structure to hold everything, which is going to invalidate the crash structure design from the manufacturer. The car will probably wind up being less safe in a rear end collision.

The motor and battery controller stuff is fairly complex. There's DIY kit stuff for doing this with lead-acid batteries, but lithium ions are a step beyond that and I don't know how doable that is on a kit level. You're also talking about adding 500 pounds of motors, batteries, driveshafts, etc to the trunk. That's going to eliminate most of the storage space, and will likely also significantly alter the handling of the car.

So it's going to be a long, expensive project. I'm sure it could be done, given enough desire, but it's almost certainly a lot cheaper, easier, and faster to just sell what you have and buy a Prius and a 350Z.

I work with some insane brilliant kids and they had the same idea. They started with an electric motor/generator chain driven to the transmission input. Worked in 3 modes.

1. Straight 23 horse diesel that had enough power for straight cruising. Clutch on the output of the motor/generator disengaged it.

2. Electric drive only. Clutch decoupled diesel engine.

3. Dual mode where diesel and electric were hooked up both churned out power for acceleration, power shifts to diesel and motor/generator would charge batteries.

It also sit as a generator to charge batteries with regenerative braking. Adding a couple of motors in the rear would be doable as an add on. I think Jaguar runs this setup.

Bruce