I like this physics engine. I am not exactly sure how good it will be for cars. It seems to be quite a bit of overkill but I suppose I can put it to good use. Any suggestions to get the cars in game to drift? Ive noticed that they generally always go where pointed or immediately spin out.
You need to model force-dependent slip, where a tire that still has traction allows some amount of sideways slip, that is dependent on the rolling speed of the tire and the sideways force of the car. I haven't looked exactly at the contact constraint used in the modeled car, so I can't tell you exactly where to put that in, but I know it helped tremendously when I wrote my ODE car sample a few years ago.
The problem with wheelsidefriction (I think thats what you were talking about) is that it makes everything linear. Sure the car will drift around corners but it never grips either. The weight of the car should be able to add/subtract from each tire's ability to slip or grip.