Re: The collective Trg to date

[Dave Eaton <dave.eaton@minedu.govt.nz>]

this is getting to be frustrating.....

there is a certain symmetry about this which makes me smile.  it is quite clear
that the open centre diff can bite, and big time.  this is not in argument. 
any yet i've had mail from people who say "what, never happened to me".

scott: you have not explained how a torsen can transfer 70% of torque to one
axle and then switch the same to the other axle in the same turn.  you
misunderstand that the torsen is *designed* to only transfer *enough* torque
(within the bias ratio) to ensure torque equilibrium.  it is not an
all-or-nothing device.

the case you have stated (again and again) would only occur with a total loss
of traction on one [virtual] axle at one point in the turn, followed by total
loss of traction on the other axle at another point in the turn.

i mean to say, how the heck do you drive?

as i have stated, (and no-one has refuted) the lift of an inside wheel while
cornering hard with a torsen produces an entirely *desirable* torque transfer
to the rear, followed by a re-distribution of the torque to the front when
wheel contact is re-established (again this is desirable).  no hunt.  no bite. 
no argument.

in the same case the open centre diff is a disaster, and the locked centre is
similar to the torsen, but without the benefits of increased power to the rear
and so is slower through the turn.

one other point about the torsen which has escaped notice is that the torque
distribution happens *before* axle slip up to the limits of the bias ratio. 
this is a major diffence to the vc diff.

wrt the s4, the decision to fo with a rear-biased setup was to improve handling
(decrease understeer) and seems to have succeeded.

dave
'95 rs2
'90 ur-q

>------------------------------
>
>Date: Mon, 2 Mar 1998 08:49:57 EST
>From: QSHIPQ <QSHIPQ@aol.com>
>
>Dave E.
>You are missing slip angle of the rear chassis.  If the angle gets high
>enough, the rear DS will rotate slower than the front, NO wheel is up, no
>torque lost (Trg).  The torsen can and will use total Trg, because you don't
>have a traction problem yet, you have a slip angle problem.  The difference
>between fwd/rwd torsen and a center torsen.
>
>ABS.  I reiterate that for now, acceleration is the issue, not coasting or
>deceleration (braking).  The benefits over Gen I so noted, the benefits over
>other Center Diffs might not be all you think.
>
>I encourage you to reread the "unlikely" statement again on page 10.
>Extrapolate "unlikely" to a driveshaft in a center torsen.  I believe the
>exact paragraph is Jeff and my exact definition of "bite".  A slipping rear
>wheel on a center torsen, doesn't necessarily mean that the collective
>transfer of Trg is reduced as you might find on a fwd or rwd torsen.
>
>
>S4.  What is the range 60/40 TO what?  Does anyone know?  Why would audi do
>that to begin with?  1991-1998 Torsen center 75/25/25/75, 1998> 60/40/xx/xx.
>What and why comes to mind.
>
>
>Scott Justusson
>