PosiTrac

["Al Powell" <APOWELL@agcom.tamu.edu>]

Jeff said: (massive snip...)

> A classic example of control limits in differentials is the case of the
> RWD Detroit muscle cars of the late 60's/early 70's when Posi-Traction
> was the rage.  A stiff torque bias in the clutch packs made for awesome
> traction and performance on dry, and arguably some help if stuck in a
> snowbank, but if you ever drove one in low traction conditions;
> rain/snow/ice, you had better have a clean pair of underwear in the
> glovebox!  Holy S**t!! I can still remember some of the most memorable
> intantaneous 360's.

OH, yeah.  I am still the proud owner (not yet sold...) of a 1977 
chevy Monza Spyder with the 305 V-8, 4-speed and Positrac.  I have 
driven it thousands of miles aross the hills and mountains of 
Washington and Idaho on snow and ice. 

One of my hardest-learned habits in that car was NEVER to decelerate 
when entering a tight corner on snow and ice.  If I did that, the 
posi rear end would lock up and slide that sucker STRAIGHT ahead and 
aim you into the ditch.  Since the nose is quite heavy in that Monza 
with the V-8 up front, the rear end was light and the effect was MOST 
interesting.  After I powered out of this a few times, I figured out 
that the trick to cornering on snow and ice was to FEATHER the 
throttle all the way around the corner until you are ready to 
accelerate.  In that case, the posi unlocks and the car tracks 
beautifully.  Can't speak for other posi rear ends, but it's the best 
trick for that one!!

Technology.  Ain't it wonderful???????????



+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Al Powell, Ph.D.                 Voice:  409/845-2807
107 Reed McDonald Bldg.          Fax:    409/862-1202
College Station, TX 77843      
Http://agcomwww.tamu.edu/agcom/satellit/alpage.htm

"Some people can tell what time it is by looking at the
sun...but I have never been able to see the numbers."
             [From 5th/6th grade essays....]