Re: Final thoughts on Torsen diffs ... for now.

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

> >Date: Thu, 5 Mar 1998 23:26:37 -0500 (EST) >From: audidudi@mindspring.com
(Jeffrey J. Goggin) >Subject: Final thoughts on Torsen diffs ... for now. >
>>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...

yes i appreciate this, but that is assuming a break in traction, which would
make the measure of slip directly proportional to propshaft speed. the gleason
article talks about torque differentiation *before* slip occurs.

so then, how does the torsen differentiation happen *without* slip occurring,
as the article says it does?

and scott's (worst case) thesis also depends upon torsen "hunt" *before*
traction loss occurs.

> >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.

great, i'd love to hear from an expert - not that we all aren't experts mind
you...

;-)

> >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? >

yup, but you're going pretty hard, but it's very satisfying to get right...

the 20v ur-quattro corners flatter than the rs2 and so is easier to place, if
not quite as fast (although the 20v would be quicker on the twisties i would
imagine).  the rs2 also has higher absolute limits than the 20v...

dave '95 rs2 '90 ur-q