markmark206

awesome, thanks for all the great information and pointers!

Sharm

Thanks for the info-I've learned a lot looking into it.

Jet Jockey/A4 Pilot

You need one wheel on each axle (F + R) to be without traction to not be able to move.

How else would a FWD car move? The advantage of Quattro over FWD is that you have two axles producing traction. EDL works only below 50 MPH on a Quattro car and not for long because it as an overheat logic built in that will disengage it to protect the brakes. If youâ€^TMre stuck in a snow bank this becomes apparent real quickly.

qfrog Ti20

I know what happens, because I've done it many times.

" You need one wheel on each axle (F + R) to be without traction to not be able to move. "

Torsen center diffs dont like being presented with a wheel off of the ground.... slipping some and totally off the ground represent two different loads to the center torsen. Under slippage the torsen can shift torque away from the slipping axle. Conversely a NO LOAD situation at either end of the center diff yields you not going anywhere. The torsen needs to be presented with SOME load, think about EDL.. why else would we need EDL ??? oh right to present some load to the center torsen so it will remain in operation and not go into a no load situation. Remember without any load presented at either end of the center diff (wheel off the ground gets you no traction for all 4 wheels) The cente diff dumps and till you have some resistance present at both ends of the diff you will have no power being properly distributed.

YES this does happen, I shyt you not.

Think of a FWD car equipped with an open differential with one wheel off of the ground, its not going anywhere is it... especially without EDL... now lets enable EDL... the car is going to present load to both sides of that diff and the car is going to want to move. Tho the torsen isnt exactly like this... it does behave in a simmilar manner under no load circumstances.

Yes EDL works below 50mph... but it doesnt do a whole lot I can do rolling burnouts in the snow with my manual A4. Speedo can see 50mph while I'm going along at 20 or less. EDL isnt helping much, rather its not doing anything.


The ONLY Time I've managed to get an A4 stuck in the snow was at Drew UNIV in madison NJ. I was visiting Angry Alex and I got my sedan high centered on some packed snow... there was very limited traction at all 4 corners, so little that the EDL was working full time to keep the diffs loaded. You could hear the ABS pulsation as the car spun its wheels because the body was resting on packed snow.

Now if you want to really rock out with teh caulk out, go get yourself a quattro II car (b3) and lock up the rear diff... Just you try to get that car to unload its center diff, hell in the winter you can do all sorts of things with a locked rear diff. See that was what came before EDL... a vacuum locking rear diff. With a locked rear diff you can keep the center torsen presented with a loaded situation at all times unless you are a total moron and get one of the front wheels off of the ground, in which case you're screwed just like you would be if you lifted a rear wheel without the rear diff locked.

Torsen doesnt know the front of the car from the rear... so any of the 4 wheels can be lifted and that will unload the diff. This isnt FOUR wheel drive.. its AWD, we dont have 3 lockable diffs, we have a torque sensing center differential which shifts power towards where it is getting resistance from given that the other end of the diff is being presented with some sort of torque resistive load.

If we have to get together and test all of this then we will just have to.