NAC: Miata Torsen

[Dave Eaton]

no, you are confusing the haldex with the viscous diff (vcd).  the haldex is
a wet clutch driven by speed difference between the sides of the diff (axial
pumps operated by the relative speed difference provide the hydraulic
pressure to operate the clutch).  the vcd operates as you describe.  subaru
do not use the haldex, although volvo are the latest manufacturer to jump on
the bandwagon for their prototype 300hp s60 awd.

the haldex is a very nice device, fully programmable (the software controls
the operation of the leak-down valve), and fully able to be coupled into the
vehicles ecu.  quite possible to change handling characteristics for
particular situations - if you have the software.

hth,
dave
'95 rs2
'90 ur-q

-----Original Message-----
Date: Tue, 23 Jan 2001 21:19:11 -0500
From: Lawrence C Leung <l.leung at juno.com>

Haldex - Hydraulic (or is it Electric or electro-hydro, list help here?)
self proportioning. It does wait for a driven wheel to slip before it
reacts, but it is self-proportioning. It is also a non-wear part. Uses
hydraulic pressure generated by shear in the fluid to activate  (can you
say, Torque Converter in reverse?). Slip reaction can be electronically
assisted (Subaru Autobox cars). Slip is entirely within the fluid.