Re: Torsens and recovery...

[Jim Griffin <JGriff@pobox.com>]

At 11:41 PM 02/21/98 -0500, Jeffrey J. Goggin wrote:

>In the case of my Ur-Q, when it lifts the inside rear tire during an
autocross, all torque is directed to it >and the car is effectively
"coasting" until the wheel returns to the ground ... locking
the center diff
>will allow at least one of the front wheels to continue driving the
car out of the corner.  Despite the >tradeoffs that come with a locked
center diff (more understeer, slightly sluggish turn-in, less
>responsive to throttle modulation, slower recovery from overdriving,
et al), I've proven to my
>satisfaction that it is consistently quicker (an average of .5 to .6
seconds on a typical course) with it >locked than unlocked.

I've always thought that locking the center diff on dry pavement is a
"no-no". Won't this beat up on the drivetrain? I will be trying
my hand at autocrossing next month with the QSW, and I don't want to
trash the driveline (the NTB boys already did that once!!) by
experimenting with a locked diff on dry pavement if it is going to cause
any harm. If it is wet, now that's a different story... :-)

>similar to that of a car with an open center diff, as well as the
same guaranteed minimum of 1WD >under all conditions without all of
the other problems associated with a locked center diff for street use
>(harsh ride, excessive tire wear, etc.).

How does it cause a harsh ride? I've never heard that before...

I have noticed, though, that when the diff is locked (i.e. in the rain),
it takes more brake pedal effort to stop the car. Why is that? I have
some theories, but I'd rather first hear your explanation...

>>If you cc'd the answer to the list it may clear up some confusion
among others as well.

>Done.  :^)

Thanks for posting it. It makes for interesting and informative reading.
MUCH better than a Mustang thread, that's for sure...



                  Jim Griffin - Maryland, USA 
    JGriff@pobox.com
- http://pobox.com/~jgriff 
       "Perception is often stronger than reality!" 
  '92 Audi 100S -  '87 VW Quantum Syncro Wagon 
    ~~~~~~~~~~~~~~OOOO~~~~~~~~~~~~~~