RE: torsen tech 103/201

["Dave Eaton" <Dave.Eaton@clear.net.nz>]

scott, i'm all for keeping it simple, but you're still misunderstanding the
baseline...

if the torsen is at the bias ratio power-on in a turn, then there is *more*
tractive potential at rear of the vehicle than is being used.  why?  because
by definition the bias ratio means that the the torsen has *stopped*
allocating torque rearwards.  if it hadn't stopped shifting torque, even
more would be going to the rear.  in other words the realive traction inputs
to the differential from the fronts and rears means that the fronts would in
reality accept *less* torque than the torque bias ratio dictates, and the
rears would accept *more*.  to put it another way, if we're alking about the
locker, it could have a torque bias of (for example) 85% rear 15% front in
the same turn.

hence, at the bias ratio in a turn you are already seeing increased front
slip due to torque inputs vs tractive feedback.  and the torque ratio is
fixed until tractive inputs front and rear change.  so your scenario of loss
of traction at the rear causing oversteer is hypothetical in the extreme.

again, you need to re-think your scenarios scott.  if you think through a
power oversteer scenrio with a torsen, you will understand how unlikely it
is in reality.

also, reading the information from various sources, it is clear that the
designers have striven to avoid oversteer at all times.  and guys like georg
kacher from "car" are complaining about it....

hth,
dave
'95 rs2
'90 ur-q
'89 mb 2.3-16

-----Original Message-----
Date: Tue, 26 Oct 1999 14:01:51 EDT
From: QSHIPQ@aol.com
Subject: RE:  Torsen 103

This expressly means, if you are forcing slip do to steering, and it causes
a
traction input, traction input rules over slip angle input.  In the case
above, if the rear breaks traction torque shifts forward, and immediately.
If that overloads the tractive ability of the fronts, then torque shifts
rearward again.  We are getting close to the bite phenomenon.  Given the
above turning scenario, the ONLY thing that could shift torque forward is a
traction input rear.  It will shift and suddenly = U, it's a different and
priority torsen input.  However, if you haven't added any steering and
restored traction to the rear, the torsen will default to the rear bias = O
due to slip angle differences.  Each time the rear loses traction, torque
goes forward.  Each time the rear gains traction, torque goes rearward due
to
slip angle.  Can happen by lowering cf, or raising Trg.


Date: Tue, 26 Oct 1999 14:52:58 EDT
From: QSHIPQ@aol.com
Subject: RE: RE:  Torsen 201

Car 80q fully loaded, hi cf, 45m radius, accel 4m/s

According to 885140 this car will cause a torque dist of 38f/62r.  Let's
call
this an O dynamic chassis.  As you add acceleration (increase trg or lower
cf) you can cause the rears to break loose from traction argument.  As soon
I'm getting confused with the presentation Dave.  It is introducing
irrelevent (or unrealistic) variables into the discussion.  Let's stick with
*just* what the torsen does or doesn't do for now, it's easier.  We can
compare the locker or the open at a later time.  Torsens accomodating
differing speeds of rotation, is a presentation you didn't make clearly,
however it really doesn't matter, cuz it's irrelevent to the topic of
chassis
dynamics while turning.