Re: Question: 80Q "limited slip" center diff doesn't limit slip...

["Avram Dorfman" <dorfman@est.org>]

Hmm... I'm still not sure if I understand. You're saying that 4/5 of the
engine's torque was going to the front wheels, and that wasn't enough to get
up the hill? He gave it quite a rev while the wheel was in the air, I don't
think it's a question of not being enough torque.

The question remains, can the "limited slip" mechanism wear out and start
allowing full slip?

-Avram
-----Original Message-----
From: Phil Payne <quk@isham-research.demon.co.uk>
To: dorfman@est.org <dorfman@est.org>
Cc: quattro@audifans.com <quattro@audifans.com>
Date: Thursday, June 17, 1999 9:53 AM
Subject: Re: Question: 80Q "limited slip" center diff doesn't limit slip...


>
>> He went into a 2 level parking lot with a steep ramp, and drove up on =
>> the edge of the ramp so that the right rear wheel came off the ground, =
>> but all others were firmly planted. The wheel in the air spun free as =
>> the care came to a stop and started rolling *backwards* until the fourth
=
>> wheel hit the gound again (and then made a lot of noise and smoke 8-)
>
>> This doesn't match my understanding of "limited slip" which is this: It =
>> allows only a certain percantage difference in rotational speed between =
>> it's two sides. Namely, for the rear shaft to spin at 100 rpms, the =
>> front "shaft" must be spinning at some percentage of that, e.g. 60 rpms.
=
>> Well, if the rear axle is spinning forwards and the car's not moving, =
>> that's pretty much full slip, right? And if the car can go backwards, =
>> then it's really full slip, right?
>
>The Torsen senses _torque_, not rotation.  It was probably applying more
>toque to the front axle than the rear, but you were artificially not
>applying enough to overcome gravity and so didn't see the fact.  The
>Torsen Audi used in these cars doesn't go as far as a 0-100 split, so
>there's always about a fifth going even to the slipping axle.  The
>rear differential is (relatively) normal, so it spins the free wheel.
>
>--
> Phil Payne
> UK Audi quattro Owners Club
> Phone: 0385 302803   Fax: 0870 0883933
>