Torsen Test Redux w/ 88 80q

Dave Eaton Dave.Eaton at
Wed Jan 23 19:58:14 EST 2002

that's correct.  what you describe is effectively poor man's edl in

also bear in mind that ice in not close to 0 in traction terms.  usually
around 1/4 to 1/5 of the traction available on dry tarmac, according to the
studies i've read.  that is enough for the torsen to operate quite
effectively in a torsen 1 system.  sort of like the old days when 4-wheel
driving in sand.  sand needs weight on it to return good traction, the only
thing worse that too many kg/cm3 was too few.

'95 rs2
'90 ur-q

-----Original Message-----
From:	Huw Powell [mailto:audi at]
Sent:	Wednesday, 23 January 2002 11:30 a.m.

> sorry to contradict listers here, but in the scenario noted (i..e *zero*
> traction at the front, with a torsen 1 system), the car will not move.

noneed to apologise, I don't know what I'm talking about anyway!

applying the info in the paragrpahs below, it seems that the torsen
owner stuck with the front of their car on the proverbial "zero
traction" ice (or teflon?  rollers?), could apply their brakes lightly
to reduce spin up front and generate some torque, which might then allow
for some motion of the car?  In other words, apply the brakes to "go"!

Correct me if I'm wrong...

> the pricinple of the torsen (often misunderstood on this list), is that it
> allocates torque *across* the unit. i.e. it will allow approx 3x the
> to move to the end of the diff with the most traction *from* the end with
> the least (i.e. that is the *input* torque to the system), leaving the
> remainder for the end with the least traction.  if the torque isn't there
> the 1st place (as in this case), the torsen has little torque to allocate.
> in the case where one end has zero traction (i.e. it is in the air), then
> effectively little or no torque goes to the other end.
> in the later quattro systems, edl takes car of this by using the
> disc brakes to the spinning wheels (within the control parameters of the
> system).

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