Of course I can't resist commenting in this section, having owned a few rear / mid-engined cars. I'm not going to go into the physics or dynamics. Instead I'm going to recount some anecdotes. I am *very* familiar with the rear-weight-bias "pendulum effect". One time I went through 5 full oscillations before I got it back under control. Eventually I learned to cool my heels. Better not to go there than try to save it at the limit. Of course, I've decided to go racing in SRFs, so that's easier said than done.
My first car was a '58 Volkswagen beetle. Oddly enough, the center of gravity of the car is very close to the geometric center of chassis. This was proved to one day, when, trying to get a little more lift from our short-throw jack, we pushed it a bit further forward so that was nearly amid-ships, and as we lifted, we were astonished to find the car perfectly, (though precariously) balanced -- with all four wheels off the ground. The center of gravity of that rear-engined car is only a couple inches behind the mid-point between the front and rear axles.
Needless to say, that car had treacherous handling characteristics -- perhaps illustrating the difference between center of mass, and polar moment of inertia. The center of gravity might have been near the geometric center of the car, but at the limit, very counter-intuitive things would happen. They could happen either slowly or quickly, but they were rarely what you expected. Auto-crossing that car, I learned that lifting mid-corner is a recipe for disaster. You lift before you brake, and the instant you're done braking, you get back on the throttle. Doing anything else would send you into a spin.
When I was 16, I spun the car on a freeway cloverleaf. I thought if I could go through there at 40 mph in the dry, I could do it at 35 in the wet. Nope. Those 4 1/2" tires, it let go. I tried to correct, but the snap-back got me, and the next thing I knew I was looking at the car that had previously been behind me. What's funny about it is how slowly the initial over steer had been. It was on the order of a degree per second, but I could still feel that I had lost control of the car. Even more astonishing was how quickly the correction sent me back in the other direction. It was almost instant, like you experience with a go-kart.
Fast forward a few years, after I had bought this first-generation supercharged MR2. Fun car in dry weather, but incredibly spooky in the damp. Even partial throttle would produce wheel-spin in the wet. Modest acceleration, enough to keep up with traffic, would have the car all twitching and tail-happy. After a while, I got used to it. But one day I almost did myself in again. This time it was throttle-on over steer. I went around this corner that in dry weather I was used to taking flat. But that night, it was foggy (not even raining), and then next thing I knew, I was looking at the curb. I thought for sure I was going to hit the curb, and paniced. Through sheer reflex, I lifted, counter-steered, and was astonished to find I had not hit the curb, but was pointing down the road as I had originally intended.
So, rear-engined cars aren't always counter-intuitive. You cope with throttle-on over steer the same way you would in any other RWD car. It's trailing throttle over-steer that gets you: the only cure is to get back on the gas, before it even happens.
I've driven Spec Racer Fords at a number of tracks, and I can say that they are even harder to drive in the wet than that MR2. When they let go, the initial oversteer is very slow -- just like that day in the Bug (which I will never, ever forget). You think you can correct it, but you can't. Counter-steering seems to have no effect, neither does applying more throttle. If you don't sense the spin before it comes, you're done for.
I haven't driven an Elise yet, but I'm hoping that they're a little more refined than all that.
If there are any worried Elise owners out there who would like to work on their reflexes, I can offer a few suggestions. The first is to take any opportunity you can to get into a go kart. Indoor or outdoor, (indoor to start with), it will teach you how to sense and recover from an impending spin in an environment where losing control is not catastrophic. If you live near San Francisco, I recommend Go Kart Racer in Burlingame, CA. The dynamics of a kart are very similar to the dynamics of a rear- or mid-engined car, only more treacherous. If you can deal with one of those, any street car will feel like it's in slow motion.
Failing that, I recommend a Force-feedback steering wheel, and Need For Speed: Porsche Unleashed. It's worth setting up a windows 98 virtual machine for the sake of this game, as the rear-engined physics are accurate. Sensing an impending spin is really a full-body experience that can't be simulated. But this is a cheap way to learn how to respond to the steering feedback. You'll feel the steering go light just before a spin. Eventually, this will train your reflexes to recover from trailing-throttle over-steer.
Last edited by emdash; 05-10-2013 at 08:11 PM.