override 15mph diff-lock-off? - warning will robinson

[Dave Eaton]

according to audi (sae 880321), if you lock the rear diff, it can or will
lead to instability under braking, particularly if you hit mixed traction
surfaces.

the assumption obviously here is that abs is disabled.

with the generation 1 quattro, as soon as the rear diff is locked and you
brake on mixed traction surfaces, a lot of steering input is required.  with
rear locked and centre free, 180 degrees of steering is required.  audi
considers this outside the limits of controllability ("for a driver of
average ability").

with both diffs locked, over 600 degrees of steering input is required.  in
other words, kyagb.

with a torsen (which unlocks on overrun, and so is very similar in this
regard to a unlocked differential), i would expect that you would be looking
at something close to the 180 degree steering case.  not easy to control,
not pleasant, and not safe in other words.

dave
'95 rs2
'90 ur-q
-----Original Message-----
From: "Alexander van Gerbig" <Audi_80 at email.msn.com>
To: <one at humanspeakers.com>, <quk at isham-research.freeserve.co.uk>
Cc: <wbr90 at yahoo.com>, <quattro at audifans.com>
Subject: Re: override 15mph diff-lock-off?
Date: Wed, 31 Jan 2001 13:37:05 -0500

    Isn't it potentially bad for the diff be locked for long periods of time
at higher speeds?

Alexander van Gerbig -- '88 80