RE: The Definition of Spider Bite (tm -SJ) in a Torsen Center Diff

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

nope sorry not even close.  btw, the only comment i will make about your
"research" scott, is that i have't seen any evidence of it...

the basics once again:
1) in any turn the torsen locks the front/rear output shafts together and
proportions torque to the rear of the chassis.  based on traction inputs
(i.e. front/rear slip).  **as does the locker**.

2) only when the torsen hits the bias ratio of output shaft torque
differences will it limit torque transfer (at the bias ratio) and allow
output shaft speed variances.  unlike the locker which cannot limit torque
transfers....

3) neither the locker or the torsen have any knwoledge of slip angles.  they
proportion torque based solely on tractive differences between the front and
rear axles (front/rear slip).  both allocate torque to the axle with the
most traction.

4) it is realtively simple to construct scenarios for **both** the locker
and the torsen for u-o-u in a turn.  based only on tractive inputs.  for
example.  locker in a high speed/high cf turn sends most torque to the rear.
oversteer slide, torque must then go to the front overloading traction.
rears have recovered tractive ability (torque is now at the front) and get
the torque back again.  easy huh?  and i haven't even mentioned low cf.

dave
'95 rs2
'90 ur-q
'88 mb 2.3-16

-----Original Message-----

To summarize:  A torsen center diff chassis, in a turn, *can* suddenly and
without prediction, shift from an oversteer to an understeer to an oversteer
(ad infinitum) condition in a single turn.  This phenomenon I refer to as
The
Spider Bite (tm -sj) and is a nature of the torsen center differential.
This
creates a 'challenge' in controlling a center torsen vehicle in a high
performance - high cf environment or a low performance - low cf environment.
I come to this conclusion based on my research into how a torsen
differential
operates.

Definition of Spider Bite (as I understand the device, based on my research
and Dave E's):
Torsen center diff car enters a given turn, turning radius fools torsen into
allocating torque rearward -O-, which (depending on all the variables in
885140) *can* overload the rear tractive ability, which then changes the
variable affecting torque shift from a slip angle one (turning radius) to a
tractive variable (traction at the rear wheels), which per 885140, is
"independent of the forced slip resulting from the vehicles circular path",
and this shifts torque forward, causing -U-. which then *can* regain
tractive
force rear, which results in -O-, because once tractive force rear is
regained, torque shifts rearward due to turning radius.  This scenario *can*
cycle several times in a single turn.

This assumes all variables the same as 885140 except accleration(Trg)=cf
(they are the same variable for all intents and purposes).  Changing *any*
variable, *can* increase or decrease the chances of Bite, but can't
eliminate
it.

Single yes/no question Dave (/others):  Looking at the above scenario v your
research, isn't the definition of bite as I presented above, possible (I
didn't ask: *likely*)?  After the answer, you(/others) are welcome to
address
the errors of my thinking.