RE: Torsen Threads <*all*>

[QSHIPQ@aol.com]

Gary:
I'm interested in your methodology, regardless of your starting point.  I 
still see this as handing off a baton, whether your perception of that baton 
makes you a virual ruler, arbitrator, bandleader, or just satan.  My arms are 
sore.

Here's my scoop on the discussions to date, then I will let 'others' take 
over the wheel, as I have a Rally to prepare an S2 for (locked f/c/r diffs, 
btw)

The two conditions for torque allocation in a torsen center diff are:
*  Slip angle differences across a center axle
*  Traction at a given wheel

These are not mutually exclusive events.  That is to say, slip angle changes 
torque bias, so does traction.  Traction rules over slip angle in the torsen 
priority, cuz it is a traction device by design.

During your subsequent discussions, if ANY variable or thought is introduced 
re spiders, then it *HAS* to satisfy or affect one of the two above 
allocations of torque.

If it doesn't, then it isn't significant, or could be equalled with a change 
in another given variable.

If it does, it's worth exploring.  

Next, one has to ask what will the Torque Bias Ratio (TBR - tm)do in terms of 
chassis dynamics.  This isn't a huge leap, although it appears to be.  If TBR 
creates U or O, is more significant than the ratio itself.  If it *can* do 
either or both, based on it's design, then we (you, I, whoever) has the proof 
in the pudding that U and/or O can happen in the same turn with a bunch of 
fixed variables.

Bottom Line:  Dave's referenced SAE 885140 is a *must* read to anyone 
*wanting* or trying to introduce 'another' variable.  The methodology is 
quite specific in this paper, to get repeatable results.  Anything that 
wasn't significant, means, it isn't a necessary component (or reasonably 
assumed to be a constant)  to get a repeatable result.  

I am happy to discuss my experience and Dave's documents in reference to 
spiders, events and non events.  I personally think this discussion has 
gotten too far into the mud (revelation after 3 years?).  Given xxf/xxr is 
oversteer, and xxf/xxr is understeer, a torsen that shifts to O due to slip 
angle differences at less than max TBR, then suddenly loses traction due to 
that slip angle (or a ramp up of another given variable, like gas pedal 
increase) which shifts torque maximally to a U condition (that only has to be 
50f, btw) has a potential problem.  Given that cf, wheelbase, weight, 
acceleration, radius, and power are all constants in the torsen TBR 
methodology, one can easily claim that a change in any of these constants 
makes a change in the TBR, which dictates when slip angle becomes a traction 
issue, which dictates when traction becomes a chassis dynamics issue.

Since Dave E only has more questions (no answers to 885140 quiz), Phil is 
claiming alignment significant, I will relax with archived thoughts for a 
while.

Good luck, I hope this new idea works for you.  When you are done, I'm happy 
(as always) to give my .02.  

Scott Justusson
QSHIPQ@aol.com