si325i

and having the battery in the boot is better

sempers

Cosworth427; No misunderstanding - absolutely agree that the fronts cannot fully unload.. otherwise there would be no traction to produce acceleration to perpetuate the weight transfer, and the fronts would come back down Laterally we can achieve 100% transfer, but I don't think anyone (bar bikes?) can do it longitudinaly!

However, whoever made the comment about transfering weight forwards is plain wrong. You can *reduce* or slow the rearward weight transfer in many ways, but you ABSOLUTELY *cannot* stop, or reverse it, that's all! You can do things to ensure that a given FWD car has more weight on the front than a given RWD car too, but that's not the point

Now, assuming that everyone is familiar with the traction circle concept, consider a hypothetical car rolling round a circle at a constant speed. No drive is being applied, it has 50/50 weighting, and all tires are at their maximum lateral capacity.

Then we press the go pedal.

Assume it's RWD: Weight transfers back, the traction budget increases at the back, as does the traction requirement - we now need to provide forward acceleration AS WELL as the original lateral requirement. The traction available at the front reduces, and we will likely head for understeer. If we have power and we hit the pedal really hard, the additional traction budget will be outweighed by the forward demand, and the back will come round.

Play about in the middle ground and the car can be balanced on the throttle.

Now assume we're FWD: Weight transfers back, the traction budget increases at the back. No drive here, so we have excess capability. At the same time, the front traction budget reduces AND we have to provide an acceleration as well as maintaining the lateral capability. Simply put that ain't going to happen any way. The front pushes wide. The only ways to get it to point straight are 1) to back off the throttle 2) to compromise the back by left foot braking or similar.

Flipsides, on the way into the corner you are FAR more likely to turn a car with driven rears (RWD / 4WD) around because the engine overrun is adding braking to the rears at the very time when their traction circle is the smallest.

For this very reason RWD is more 'difficult' to drive. If you're at peak lateral ability, backing off is as sure to snap the back around as standing on it too hard.

Anyone who's still awake: I highly recommend Caroll Smith's Racecar (Driving/Engineering) etc books. For a real seminal text, I believe Milliken and Milliken is the business, but it's probably over my head

- Mark

scooby_si

has anyone mentioned torque steer yet lol
Si

Dracoro

IIRC torque steer on a FWD happens when there are uneven length driveshafts. If they're perfectly even then torque steer shouldn't happen.

My old Corrado VR6 didn't torque steer, nor did my mk2 16v but my dads old passat (e reg at the time) did like to be undecided in which direction it was travelling under heavy acceleration

si325i

i though torque steer was when one wheel was getting power and the other not.?? uneven length driveshafts? i think not.
Si