jhoeppel

Anybody know how the quattro and the ESP systems interact? That is, I know that the haldex clutch is supposed to engage as soon as 10degrees of slippage is sensed in either of the front tires, and then it begins to share torque with the rear wheels. But from what I've gathered, the ASR (fwd)/ESP(q) systems also seem to be triggered by wheel slippage, amongst other inputs. How do these systems interact? Does quattro engage first, and the ASR or ESP systems only if things continue to deteriorate?

I was playing around in a lightly snow-covered parking lot this morning (not too aggressively, as I was arriving at work and it was their parking lot!) but my seat-of-the-pants sense was that the transition to quattro was seamless. Not sure the ESP system ever came on, as I was looking out the windows steering, not paying attention to the speedo display.

~john
1st time quattro owner ('01 180TTQC)

M power this!

your Haldex is very quick. but as the car feels (now all 4 wheels) slip, it enacts the ABS to stop the slipping wheels and cut engine power at the same time. ESP is more a spinning of the car. it still uses ABS but looks at steering wheel angle and arc the car is traveling. if they're not the same, it grabs the brake needed to correct that. if you didn't feel anything, you still had traction.

jhoeppel

The ESP button was normal (light not on), and I didn't feel any ABS action at all, so from your response I'm thinking it didn't need to activate--in fact, none of the wheels slipped. Not too much snow, and brand new M3's so I suppose I shouldn't be surprised. But I'm just not used to the (front) wheels not breaking loose and spinning when horsing around in a snowy parking lot, new tires or not.

Kewl! Thanx.

mkysteel

Also looking for some technical advice, it seems to me that the conditions for the ESP/Traction Control and the Haldex to engage actually contradict each other.

i.e For the Haldex system to engage, it must detect the front wheels slipping in order to transfer some power to the rear wheels. However as soon as the front wheels would have slipped, the ESP would have also detected this and limited power/applied the brakes to the relevant wheel in order to control the car. Thus the haldex system would be disengaged before the driver was able to even experience the benefit of having 4 wheel drive?

It seems very contradictory, I'm struggling to understand the relationship between the two systems. Is it better to turn the ESP/ASR systems off if the benefit of having 4 wheel drive is actually desired?

Any help greatly appreciated!! :-)


Audi TT MK2 3.2 V6 Quattro

Eddy B

Agreed. Blows my mind that there's not more info on that.