AvramD

Does anyone know if sustained 2 & 4 wheel powerslides are possible with EDL? I know that it senses differences in wheel speed between left and right, and slows down the faster wheel (I assume that it's going on speed & not torque since it's just using the ABS sensors). I was told by someone at AoA that EDL does *not* compare front to rear axle speed.

In theory then, it should be possible for it to make the left & right wheel speeds match on an axle, and maintain that matching speed *with wheelspin*. Furthermore, it ought to be able to make this happen on both axles, independantly from one another.

How close does it come in reality? If it doesn't do this, has anyone looked into chipping the EDL? For that matter, is EDL controlled by the same chip as the ECU? Is it even possible to reprogram the EDL?

The thing that is so cool about EDL at least in theory, is that it *is not* traction control. What we as drivers really want (IMO) is to be given access to as much traction is available, and then allowed to exceed it *uniformly* as we see fit (assuming enough power is available). So, I'm wondering how close EDL gets to this, and how much closer it *could* get.

I know a lot of us have these dreamy visions of owning an RS4, and lighting up all fours at a stop light. I'm wondering if it could ever really happen, even with a million lb-ft of torque. Of course the question is just as relevant even to an unmodified 1.8t owner in low traction conditions.

It seems to me that uniform power distribution under slip conditions - give as much power to each wheel as the ground there can handle, and then deliver extra power in direct proportion to how much each wheel can handle. Now this is dreamland, but any selfrespecting 4kq owner can tell you that simply making all wheels spin at the same speed comes pretty damned close to delivering this!

Anybody else have differing opinions? Anyone done any emperical testing to see how it really behaves? Most important, does anyone *really know* what the algorithm is?

AvramD

2nd to last paragraph should star out with

"It seems to me that -the best control would come from- uniform power distribution..."

For example, if 3 wheels have 100 lb-ft of traction, and the fourth has 50 lb-ft of traction, and you deliver 350 lb-ft* , then each wheel gets exactly the right amount. Then, if you deliver 10% more torque, an extra 35 lb-ft, each wheel gets 10% more than it "needs", i.e. 3 get 10 lb-ft, and the other gets 5 lb-ft.

Note, as always this is a simplification, since once a wheel starts to slip, the friction coefficient changes - the algorithm would have to be very dynamic. But you get the point 8-)

* recall that an S4's 1st gear ratio is 3.5:1, and it's axle ratio is 4.11:1, so in 1st gear, torque is multplied by 14.4, and it only takes 25 lb-ft of engine torque to get 350 lb-ft at the wheels. This scenario probably describes dirt or snow, and *every* quattro built has been able to deliver this much power.