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

Taka Mizutani t44tqtro at gmail.com
Tue Mar 8 22:15:13 EST 2005


Keith-
Thanks much for the informative commentary.

Can you elaborate further on the Nissan system and which car you're thinking of?

I thought ATTESA-ETS as used in the R34 Skyline GT-R (last iteration)
was computer controlled center and rear diffs, more like the Porsche
959. I know that the car has some sort of computer controlled rear
diff, they made a big deal about it in their literature, although I
can't really read it. :-)

I don't know what differences there are between this particular
iteration and that of something more readily accessible to us in the
States- like the G35x and the FX35/45.

Aren't these computer controlled diffs basically acting the same as
Torsen in terms of the end results?

Finally, I don't see why anyone doesn't make a Haldex system that is
the reverse of how it is setup on most of these cars- why can't they
make one that is RWD until slippage occurs, like the X-Drive you
mention? Is it due to packaging? I think making something like the
Volvo S60/V70 AWD into a RWD biased system would be nearly impossible
without a complete redesign, due to the transverse engine layout,
transmission setup and the like.

However, with something like the G35x....???

Taka
needing an ME to figure out some of this stuff

On Tue, 8 Mar 2005 19:30:53 -0500, Keith Maddock
<keith.maddock at gmail.com> wrote:
> 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
>


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