Re: A4 Electronic locking diffs... (kinda long)

[dan_masi@MENTORG.COM (Dan Masi)]

On Oct 12, 12:25pm, Andy Poling wrote:

> Now, upon reading what I've just written about the operation of
> Torsen diffs, I can't help but wonder if the center Torsen diff
> on my A4Q won't end up fighting with the EDL if, say, both wheels
> at one end lose traction.

No fight.  Say both rears are on ice.  The Torsen then causes 80%
of the power to go up front.  20% is left at the rear end, and
EDL will do it's best to get both rear wheels to drive.  The
key is that EDL doesn't work over the entire car... it's a
per-diff setup.  This would imply that it's never going to
brake BOTH wheels simultaneously, and that's the only way you
would end up fighting the Torsen.

> I think the result is that the Torsen will only come into
> play above 25mph when the EDL is no longer active

No need, plus awfully difficult to do, since the Torsen is
mechanical (can't turn it "on" or "off").

> I still think the ultimate solution would be Torsen diffs in
> all three locations, front, center and rear.  Can anyone offer
> a reason why this is a bad idea?

1) Weight
2) Cost
3) Space
4) Fuel efficiency

It'd be the ultimate solution if it didn't have any of those
drawbacks.  I guess the nice thing about EDL is that it
almost comes for free, in terms of hardware.

Dan Masi
'96 A4Q