[s-cars] Worthy projects (was Alum..was UrS $)

QSHIPQ at aol.com QSHIPQ at aol.com
Wed Apr 25 14:37:28 EDT 2007

In a message dated 4/25/2007 10:49:24 A.M. Central Daylight Time,  
keith.maddock at gmail.com writes:
>Someone else might remind that a torsen  in a Audi is probably never
>50/50 unless standing still. For normal  driving, Torsen torque
>distribution will always match the F/R weight  distribution (assuming
>same tire/surface friction coefficient F vs. R),  up to the max bias
>ratio of course...

Very true Keith, more specifically the ONLY center diff with 50/50 torque  
distribution is an OPEN DIFF.  The torsen mimics the locked diff in that  torque 
distribution follows weight distribution in straight line acceleration  (up 
to max TBR).  
Regarding 'future', what it's really going to take from one of these two  
players is a Torsen coupling differential lock or a Haldex coupling differential  
lock (specifically Haldex with a differential, couplers don't have center  
Both have the technology is my understanding, need the buyer.   Currently, 
audi and volvo appear to prefer the fwd with rwd coupler for the  Haldex.  
Cheaper, better gas mileage, and most likely better default  (understeering pig) 
If you have never driven a coupler over center diff, it changes your desire  
in a big way.  My DD landcruiser with supercharger has full time awd with  
center diff, VC attached, and the ability to lock the center over the  VC.   The 
best of all worlds IMO.

>PS Scott - I don't suggest you ever apply more than 2.25V (CAN-LOW)  or
>2.75V (CAN-HI) to a CAN bus , regardless of how much you want  to
>lockup the haldex.. :)
We've had some interesting discussions with Haldex on the issue.   Their 
claim is that full lock is well within the design parameters of the  device.  It 
also might be worthy of note that the 'overheat' problems  identified are not 
associated with full lock, but with limited slip  torque allocations prior to 
full lock.
S"torsen boy" Justusson

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