FilipeS3

Hello:
I would like too know if the quattro system is always active ? or better, if the 4 wheels are always pushing or not, because some guys say that the quattro system only works in dificcult situations of traction. Are they always pushing or in normal driving only the front wheels push ?
Thanks a lot, sorry my english.

Filipe Jesus

2001-s3

I was told by a 'Reporting Engineer' from my dealer that there are no pre-configured ratios like in some other 4wd cars (ie 60/40) etc.. The S3 quattro system is supposed to be infinitely variable & is constantly being computer monitored / controlled to achieve maximum traction. - So there are no 'normal' ratios (I asked the same question that you did)..
Furthermore, in normal driving you won't see the ESP symbol on the dash flash while the car's brain is adjusting wheel spin / braking - you'll only see it flash when you are pushing the ESP (normal) tolerances - ie. thrashing the b@lls off the car & actually making it work.. The light is a warning to the driver that you are really making the car work - take it easy!.. I haven't yet been able to do comparisons to see how much better the ESP is at driving than I am!>..

AudidudeNZ

The haldex is the centre differential and is responsible for dividing torque between the front and rear axles. It is used in VAG AWD cars that have a transverse mounted engine (Golf/A3). The longitudinally mounted engines (Passat/A4/A6) use a torsen centre diff and this is the traditional quattro setup. Audi muddy the waters by calling the haldex setup in an Audi "quattro" (A3/S3)and the torsen setup in a VW "4motion" (Passat).

In normal straight ahead driving it is 100% to the front (the torsen system is 50/50).

As soon as any slip occurs between front and rear there is virtually instantaneous (within 15 degrees of road wheel rotation) transfer of torque to the rear wheels. Remember that when turning there is always slip between front and rear - the fronts turn more than the rears.

Therefore your advice that the S3 quattro only works in "difficult situations of traction" is very wrong. It is always working EXCEPT in straight ahead travel (and who needs it then??). Except of course if there is wheelspin and then of course you will get all the advantages of AWD instantaneously.

Do not confuse the Haldex with the ESP system - the latter does only come in in extreme situations and is able to control the traction AND braking forces at all 4 wheels independently, As part of this control it takes control of the Haldex as well to optimise F/R torque split.

I have driven both Haldex and torsen systems extensively and hard, and this experience combined with information gleaned by wasting huge amounts of time on this forum for the last 6 months has lead me to the following conclusion about the two setups:

Haldex is more capable than torsen of delivering traction to the road at the extremes of adhesion, simply because it has a wider operating range - 0 to 100% vs 30 to 70% in the torsen.

HOWEVER: because the Haldex can transfer so much torque and so quickly, it has the potential to unblance the car more in some extreme situations. This, I believe, is responsible for the "TT problem" which has now been addressed with aerodynamic mods and ESP. I have never experienced this yet but it is always on my mind when pushing the limits. The S3 is much more stable aerodynamically than the TT.

In practice, in slippery conditions, the torsen feels more benign and predictable. The haldex is quicker and more exciting. My friend has an RS4 and when he is battling understeer my S3 is squirting out of the corner in full traction. You get a delicious RWD feel exiting roundabouts and sharp corners (except if you overcook it. Then you get huge understeer).

Sorry to be so long winded (regulars are used to me ).

Cheers