RE: Haldex Research results II

["Dave Eaton" <Dave.Eaton@clear.net.nz>]

> -----Original Message-----
> From: owner-audi-s-cars@lists.boldfish.com
> [mailto:owner-audi-s-cars@lists.boldfish.com]On Behalf Of QSHIPQ@aol.com
>
> In a message dated 9/9/99 7:04:40 PM Central Daylight Time,
> Dave.Eaton@clear.net.nz writes:
>
> >
> >  2) you're not correct about this 50% maximum torque transfer thing.
there
> >  is nothing which i see in the design which limits torque transfer
(unlike
> >  the torsen).  as far as i know, based on the haldex literature i have,
the
> >  coupling will transfer 100% torque either way.  just like the
generation 1
> >  quattro system.  when the coupling is locked (joined, whatever) you
have
> >  100-0-100 torque transfer possibilities by definition.
>
> How is that possible Dave?  If the primary drive axles is fwd, then you
have
> lock, if the front slips EDL kicks in,  Trg reduces.  Hardly just like the
> gen I system, in fact it's not at all like it.  My understanding of the
> Haldex system is you either have all fwd or 50% rwd.  For it to be more,
you
> would need to have different FD ratios to the rear axle, in the front
> transmission.  Claiming it has more than 50% capability, means that the
> Haldex is capable of massive understeer and massive oversteer coupling and
> uncoupling the rear axle.  Not the case here.  If EDL is used on the front
> axles, the transfer of torque can not exceed the highest Trg of the
highest
> traction front wheel, by definition.  EDL is a potential mess here.

you're misunderstood the effect of a locked clutch between the axles.  once
that sucker is locked, the effect is exactly like a generation 1 locker.
solid link, and torque can flow front to rear 100%:0 and visa-versa.
depending upon grip of course.  examination of the haldex documentation also
makes this clear.

certainly edl operating across either axle could limit the torque transfer
but for example, picture the front 2 wheels on ice and the rear on tarmac.
pretty much 100% torque to the rear regardless of edl operating across the
front axle.  only when edl operates across the axles with the torque
transfer be limited all the time.

massive understeer and oversteer?  not sure, depends upon the computer i
guess, and the application.  need to drive the audi application to find out.
certainly most testers say that the ttq and the s3 are capable of lift-off
oversteer.  we'll see:-)

> Again, looking at the comparo, I'm convinced that Haldex should take on
the
> gen I locker locked in position 2.  I'm not enamored with the Haldex,
sorry.
> It's a step from the torsen, but 180 degrees from the norm.  One major
flaw
> in the logistics, IMO.  Audi hasn't had big gains in proving btdt wrong in
> the torsen arena.  Better luck here?  I'm not as optimistic as you.
Another
> 6 years of "proving" everyone wrong, that makes a total of 16.  Even if
they
> prove to be batting 1000 with the Haldex, that's still less than a .500
> batting average.  Quattro advantage indeed.

mmm... toyota's performance with a hang-on-clutch in the wrc machine would
differ about state-of-the-art.  with their haldex copy they were within a
whisker (500metres) of the world championship last year.

about the haldex, the road testers disagree with you about the experience.
interesting call to say that, with sales at 10-year highs, that the punters
don't disagree with you as well.  like i've said, lets leave the black board
and drive the machines.  very big call to pan the technology without having
done that methinks...

dave
'95 rs2
'90 ur-q
'88 mb 2.3-16