(no subject)

[Edward R. Wendell IV]

Rokas,

EDL as Audi refers to it is perhaps one of the most misleading 
automotive acronyms ever. It doesn't lock the differentials at all. The 
center diff is the famous torsen, a mechanical type of limited slip 
differential. It works completely on it's own controlled by internal 
friction and worm gears. The front and rear diffs are standard open 
differentials identical to the one in your front wheel drive car. The 
so called Electronic Differential Locking is actually an offshoot of 
the ABS system that is used to control wheel spin on the front and rear 
diffs. Using the input from the ABS wheel speed sensors, the EDL 
control unit (not sure if it's actually part of the ABS controller) 
applies the brake to any wheel that is spinning faster than it should 
due to loss of traction. Due to the action of a standard open diff, 
applying the brake to a spinning wheel causes power to be applied to 
the non spinning one.

As to how to drive it or whether or not you can feel the EDL working I 
have no idea. I've only had limited time in a friend's a4 and sadly 
didn't get a chance to flog in in a snowy lot, at least not yet : ).

Roy Wendell
Clarksburg, WV USA
86, 87 5kcstq