Limited slip

["Smith, Kirby A" <kirby.a.smith@lmco.com>]

Phil said:
The rationale behind the speed-limited lock on the ALZ, BTW, seems to be
that a 
limited-slip differential needs centrifugal (centripetal?) force to
work, and 
this is not sufficient below 25mph.  Above this speed, the limited-slip 
function is available and the driver-operated lock is
counter-productive.

I say:
Velly intellesting!  I haven't a sticker in my 90q trunk to check, and
haven't yet had a chance to check my wife's 90q, but ALZ seems to ring a
bell with a recent casual tour of my Bentley.  A centipetal limited slip
-- my only experience is with the Chevrolet friction disk approach used
in my Corvair.  Is the lockup based on common-mode wheel speed, or
differential wheel speed?  Common mode, I hope.  Then ideally, one would
want to tune the manual lock disconnection speed to be just below (or
above?) the point of centripetal effectiveness.  And how is the
driver-operated lock counter-productive if both are operational, other
than interference with ABS?  How does ABS work if the common mode speed
is high and the differential is running in limited slip mode?  Is it a
centripetal actuation of a friction system?

         ....  Kirby  (kirby.a.smith@lmco.com)
                   New Hampshire, USA
                      2 X 1988 90q