Final thoughts on Torsen diffs ... for now.

[audidudi@mindspring.com (Jeffrey J. Goggin)]

>central to this point is whether the torsen uses *rotational* shaft
>speed differences as the determinant of the torque bias to apply, or
>whether it uses forces *from* the driveshafts *into* the diff to do this
>(ie. effective traction, or torque reaction).  I am convinced that it is
>the later.

Take a look at the bigger picture here ... how are the four contact patches
connected to the center diff and, ultimately, how do they communicate with
each other?  Through the propshafts, which rotate, faster of slower, as
appropriate to the circumstances...

Re-read Section 5.2 of the paper I posted *very* carefully (hint: substitute
the phrase "end of the car" for "wheel" to adjust for the front/back
orientation of the diff) and this should become clearer to you.

>btw, just in case it needs to be stated in this public forum, i welcome
>this discussion as it helps us all understand our cars.  no ill-feelings
>or heat from this kiwi bloke.  my (longstanding) invite to scott, jeff
>and others for a drive in a station wagon shopping basket in godzone is
>still on the table....

I'm glad to hear this (although I already suspected as much).  For my part,
I intend to do some more homework on this issue -- I believe I've tracked
down the author of the paper I posted and will be talking to him soon and
I've got calls into the Gleason Corp. that haven't been answered yet -- and
will post back here when I've got some additional info (and not just hearsay
and speculation) to pass along.

BTW, one thought I had while driving home this evening: Perhaps the reason
us Type 44 owners have experienced the "Torsen hunt" and the Ur-Q owners
haven't is the fact that it's very rare that a 200q will lift an inside rear
wheel, even driven at the limit, whereas an Ur-Q will lift an inside rear
wheel nearly as often as a dog lifts its leg on a fire hydrant (I've yet to
drive an Audi that lifts a front wheel ... will an RS2 really do this?).
Food for thought, eh?

Until then...  :^)
 
______________________________________________________________________
    _                _
   / |      _| o    | \       _| o   Jeffrey Goggin
  /__| | | / | | __ |  | | | / | |   audidudi@mindspring.com
 /   | |_| \_| |    |_/  |_| \_| |   http://people.delphi.com/audidudi
______________________________________________________________________