Question about FWD, RWD, 4WD and their impact on cornering.

I've been wondering......how does the behaviour of a car change between a front wheel drive, a rear wheel drive and a 4 wheel drive configuration.

For instance....let's say I'm taking a corner in a car that can "magicaly" change it's traction configuration. The first time I go trough the corner in neutral (no traction on any tyre), the next time I go around it with rear wheel traction, the next time with front wheel traction and the last time with all wheel traction.

Which is more likely to cause more oversteer, understeer or neutral handling?? Which configuration would be faster trough the corner (suppposing that the car doesn't slide and that it has the same mass and grip)? and finaly....what is the physical explanation for that??

My guess is that 4WD produces neutral handling, RWD oversteer and FWD understeer but I don't know why that happens.

The best explanation I ever read of this was in Paul Frere's classic book "Sportscar and Competition Driving", which is a must-read for anyone interested in how vehicles handle. The full explanation is far too detailed to go into here, but suffice to say that RWD will usually produce eventual oversteer (but not necessarily, depending on the way you drive and whether your car has enough power to break rear traction), FWD will nearly always produce understeer, and 4WD usually gives neutral or slight understeer tendency. Having said that, I've driven MX5s and Ginetta G15s (rear ENGINED, as well as RWD!) which I've had understeering through corners by going in too fast and not getting enough power down early - it's the nature of physics and the way a car turns into a corner that the front wheels will always push a little, giving initial understeer. I've also seen FWD Golf GTis on opposite lock as the mass of the rear end eventually breaks away under extreme provocation - it depends on how you drive and how you have your car set up, as well as on which wheels are driving.

I watched a 911 that was set up to push, but usually under steady state cornering on a fixed radius ie a circle the more heavily loaded or hardest working tyres break first.

graham

I have found every porche that i have driven around the track to always understeer (some like pigs!)due to squat understeer from the motor being so far over the rear wheels, even gutless ones!
I was once asked to honestly give my opinion on a very highly developed turbo 911($$$)to the owner and all I could blurt out was "it,s a vee dub (beetle) on steroids, um sorry? ".

nice one,
The tecnical term for an ill handling 30 odd year old pile o **** is "its a drivers car"