[s-cars] EDL fails (but my new 22's worked great!)

[Keith Maddock]

Taka Mizutani <t44tqtro at gmail.com> wrote:
> Yes, but lockers are even better- the STi with locked center and
> Torsen rear does 4 wheel roostertails all day long in deep snow. :-)
> 
> The Volvo does asymmetrical roosters- the Haldex system transfers
> torque all over the place and causes the car to crab-walk up inclines
> while throwing snow all over the place. :-)
> 
> I'd like to hear Mike and Keith's input on Haldex- is it a better
> system than quattro IV w/ EDL?

My answer is no :)

I'll take a torsen center over a front-biased active coupling nearly anyday

My opinion could change if the front-biased active coupling was one of
the latest generation ones with "feet forward" coupling commands
(latest haldex's have a small electric pump to generate clutch
pressure before the wheels slip)  that was calibrated appropriately to
remove the FWD tendencies.

Even better is the rear-biased active couplings, I really like these
as long as they have good response times...  Lots of the American
truck "Auto 4WD" transfer cases are basically this but they have
really slow reaction times.  This is what BMW's X-Drive is, and it is
really slick, very well integrated with the stability control at least
on the X5 that I have experienced.  Perhaps Michael knows if that was
a Bosch or Teves stability control on those cars, and how much of that
benefit was the part of the stability control, and how much was from
the transfer case controller.

Still, for the price, its hard to beat a Torsen! :)  

What would be really interesting is to take Nissan's system which uses
a clutch to connect a center diff (rather than just a clutch to
connect the front axle), and then change their open center to a
torsen.  So you could have RWD dynamics and a great AWD dynamic, with
computer control. all in the same car.  Tasty...

Cheers,
Keith