[torsen] Re: Torsen torque split clarification

QSHIPQ at aol.com QSHIPQ at aol.com
Mon Dec 4 11:35:13 EST 2000


In a message dated 12/4/00 9:54:25 AM Central Standard Time, 
graydon at apollo.kettering.edu writes:

> It was _my_ opinion that if you adjusted the friction unequally (front vs
>  rear), you could achieve a static torque bias to the rear so that more
>  torque goes to the rear under all conditions.  That might stop the
>  instability of the centre torsen a little.  I'd sure like to try it. 
>  
Hmm. defining that might be tough graydon, and could very well bring more 
problems than solved.  If you agree that a T* car has O at a given split, 
let's say 65r/35f, and you will have O from 65r/35f>78r/22f, then you shim 
for 71r/39f and have +/-6.5 torque transfer f/r.  Any number other than that 
will cause a U problem somewhere in the torque applied traction equation, 
without a serious weight redistribution, which I consider a given.  

I think you are looking at it backwards, Jeff G looks at it correctly IMO.  
If you have a baseline chassis that is of fwd U character, looking at the 
above example, you could have 43r/57f +/-21.5 of predictable U, with a larger 
BR.  Drive the car like a fwd car, stop trying to make an fwd car be a rwd 
car (thinking of how much money audi spent moving the A4 btcc engine 6in 
rearward comes to mind)

Addressing any or all of this in terms of ABS/edl function is another 
consideration.  If this doesn't allow abs function, then I'm not at all sure 
that the locker wouldn't end up being the better way to skin the cat.  When 
you start working thru the practical engineering of this whole idea, that 
locker doesn't seem all that bad.  That appears to be audis way of thinking 
to this day.

Bensingers comments on "...reckons O to be at xx/xx split..." means that you 
have O and U in turns.  This enfatuation with O in a U chassis car doesn't 
make any sense to me at all, you might have reduced the traction argument U 
slightly, but you haven't really addressed fully the problem of turning 
causing changes in torque allocation.  In your example, raise HP or lower Cf, 
you are back to square 1 in terms of effective resultant chassis behavior.

SJ



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