RE: real quattro

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

my point is simply that "part-time" awd systems have been around for years,
and used by nissan, porsche, lambrghini and others, to very good effect.
generally the theory is all the same, with all the torque going to an axle
until slip where torque is sent to the other pair of wheels.  whether the
chassis is fwd-baised or rwd-baised is immaterial.  (interesting insight
into this is the "performance car" interview with the porsches' designer of
the original c4 system).

what interests me in the design is the ability of the processor to change
the handling dynamics.  i expect, at this premature time, to find the s3 and
ttq quite differet handling animals...

the point is moot really.  why?  because even with a state-of-the-art active
system, you will certainly have times were little or no torque is going to
an axle, so you are not strictly speaking awd at that time.  also, with the
generation 1 system locked, you will have times where the same is true, that
0% torque is going to an axle.  whither awd then?

anyway, this whole argument is a little premature (par for the course?).
lets drive the cars equipped with the devices, and then make up our minds.
i'm certainly keen to drive the s3 as i'm almost convinced tracey to part
with her mk2 vw gti :-)

btw, has anyone thought of the differences between the haldex implementation
and the ususal vc-based awd implementation (e.g. subaru, lancia)?
intersting ain't it?

driving report next week...

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

-----Original Message-----

Date: Thu, 9 Sep 1999 08:59:09 EDT
From: QSHIPQ@aol.com
Subject: RE:  Real Quattro II

Dave E writes
>some examples of similar awd systems to the haldex come to mind:
>1) nissan atessa (used in the skyline notably the gtr -aka godzilla) where
>100% rwd usually then torque sent to the front axle on slip to a 40% limit.

rwd to awd
>2) lamborghini ditto.3) porsche c4
rwd to awd
>4) the 1997-98 toyota corolla wrc rally car (toyota looked at the haldex,
and ended up delevoping something very similar).
rwd to awd

The first question we must ask, based on "similar" technology, is, why fwd
to
awd?  A baseline chassis dynamics problem?

>not sure how you can say whether or not the haldex is "an active
>differential in terms of performance or advantages".  i personally have yet
>to drive one, and when i do next week (s3) will prpbably find it quite
>different to it's other implementation (ttq) when i drive that.  afaik,
very
>few people on the list have actually driven a haldex quattro.

And you will compare it to what?  I think you can say it based on the
history
of it's use, and the baseline that fwd to awd gives what in terms of chassis
character.  If the haldex locked goes 50f/50r you have understeer, then
more.
 If you have haldex locked 25f/75r you have understeer, then oversteer.
Sound familiar?  This isn't real quattro, this is fwd with extra traction.
>From it's baseline design, we know what the inherent handling of the car
will
be.