Re: Audi Kool-Aid, Pt. II (long)

[Josh Pinkert <flush@radix.net>]

At 10:42 AM 1/26/98 -0700, Lawson, Dave wrote:

> About 2 or 3
>years ago a discussion about the handling traites of Torsen cars was
>started and then went off-line between a few people. It would be nice if
>some of this info surfaced and I am sure many of us can benefit from it.

I would like to see this as well.

>1989 and the torsen car is a huge difference. During dry and 7/10s
>driving there is not much difference but when road conditions degrade
>and driving at the limit, the torsen car is quite different. You can
>break the back end out on the wagon much easier than the ur-q. This is
>very noticable on icy pavement. I have to work the ur-q very hard to get

I'm sure other listers can back you up here, but I've owned two torsen
equipped quattros, both of which I haven't had any problems with at 10/10.
Some of your 'balancing' problems might be a result of the wagon factor.
My former torsen quattro was an '88 90q.  I hammered it quite a bit, and it
was the BEST snow vehicle I'd ever driven.  It could grunt through deep
snow and climb icy hills with little trouble.  Point and shoot...  My
current is an A4q.  While I haven't really had a chance to explore the
slick road handling (snow/ice), I have been autocrossing it.  There's a
good amount of understeer, and if I stand on it while understeering hard
(coming out of a hairpin), the torsen will make some groaning noises.  But
it's completely controllable and predictable.  The tail is always well
planted when on the throttle...through all speed ranges.  OTOH, I did
manage some trailing throttle oversteer...more like drift, while moving
decelerating through a fast switchback.  But again, nothing twitchy or
uncontrollable.  Of course, ice is a different story.

My guess is that any flaws in a quattro system would much more pronounced
on a slippery surface at 10/10 than on a grippy surface at 10/10.  But then
again, in terms of all out performance, one really needs to evaluate the
effects of the different quattro systems across all types of road surfaces.

>Audi knows that for 10/10ths handling you don't put a torsen in the
>center diff position. Just review the quattro race history and you won't
>find one mentioned anywhere. For this type of application they turn to
>different technologies including no center diffs or sometimes viscous
>couplings.

VCs are slower to react and not as abrupt as a torsen.  This might make
them better suited to re-distributing power at 10/10.  Hmm...I wonder why
Audi stayed with the torsen on the new S4 (although they did alter the bias
from 50/50).



- Josh Pinkert
- flush@radix.net
- '98 A4q 2.8
- ISO '72-'73 or '78-'83 Porsche 911