It's been over a decade since the last of the Kappa sports cars from General Motors rolled off the assembly line. In the United States, the platform-sharing lineup consisted of the Saturn Sky and Pontiac Solstice, but abroad, the Kappa was known as both the Daewoo G2X in Korea and the Opel GT in Europe. Whatever version you got, it shared a lot of parts with many other cars. Radios, steering wheels, HVAC controls, and more.
This is typically seen as a bad thing. Sports cars should be special, and sharing parts with the lowly Chevy Cobalt was never seen as a premium feature. The parts-sharing and cost-cutting measures went further than you think, though. In at least one instance, it has unintended benefits.
In an apparent effort to save money, the Kappa cars all use the same wheel bearings front and back. This may not seem that unusual, but it is pretty strange. Most RWD cars from BMW, for instance, have two different sets of bearings. The rear wheels are the only ones being driven. Therefore they are the only set with splines to mate up to a CV axle. If you shop for Saturn Sky or Pontiac Solstice wheel bearings, you'll notice they are all the same no-matter the corner you need. Likewise, the back of the front spindles even has clearance to accommodate an axle.
The reasons for that are unclear. So I'm going to go off the deep end on this beautiful Monday morning to explain. Join me, won't you?
I used to own a Sky Redline. It was a lot of fun. With a tune and a set of new MAP sensors, it was a 280-wheel-horsepower car with great steering, a short wheelbase, and the transmission right out of a pickup truck. If I still had it, I would be crawling underneath trying to figure out a way to convert it to all-wheel-drive.
Conventional AWD would be a huge pain to add. Just ask friend of the website Tim Roman, who converted his S550 Mustang to spin all four tires in anger. It takes a lot of time, skill, and patience to do. I only have the first of those things.
The easier way to do this would be a hybrid system, similar to the one I'm putting together now for my lightweight sports car project. In essence, this means a homebrew electric front drive unit combined with a battery and inverter. Without going extremely high voltage, you could still get 50 kilowatts to the front tires, a respectable 67 hp.
There's at least one good mechanical part about the Kappa platform which enables this, in theory. The engine is set very far back in the engine bay, which means there's a fair amount of space between the front face of the accessory drive and the back of the radiator. I think if it needed to be, the radiator could be shrunk vertically and made thicker to add some more space for a motor and differential.
The hardest part about all of this is making room for the axles in the suspension. The front shocks would have to be relocated, changed out, or both. I think the best solution would be to add a fork at the bottom of a new, shorter strut to go around the driveshaft, similar to the Corvette E-Ray's arrangement. This would take a lot of time and expertise to get right. Likewise, I'm willing to gamble that a fair amount of the underbody structure would have to be cut up and then reinforced.
As far as other details like battery location, that's an easy one. The Kappa's trunk is laughably useless anyway, so filling it with power-dense batteries would finally give it a purpose. Likewise, this would offset the weight of the new front drive unit.
Overall, this is just a theory. Converting an admittedly niche car to an all-wheel-drive hybrid would be a big project. The fact that some of the Kappa platform's parts-binning makes this doable at all is funny, though. It would definitely be cheaper than putting a V-8 in the car, which is easily the most common big mod people do to these things.
If you're looking for a project and you've got a couple grand burning a hole in your pocket, it's worth getting a little weird.
