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RE: Bites of dead horses, last post for me

the difficulty with all current awd systems is, as phil has said, their
integration into the electronics.  with "edl" audi has added a (mechanical)
feedback loop into the operation of the chassis.  and a method on indirectly
controlling torque shift in the chassis.  with "esp" there is a further
feedback loop to decrease torque input to the system if required.

all the manufacturers are attempting similar things with their various
systems, with similar reasoning.

clearly the more direct this control is, the more integrated it can become.
imho, we will be seeing more and more "active" differentials.  you could
argue that the elements of this are already in place in the nissan attessa
system used in the r34 nissan gtr.

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

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

Date: Wed, 22 Sep 1999 10:47:42 -0400
From: "Eric Renneisen" <renneie@hlthsrc.com>
Subject: RE: FW: Bites of dead horses, last post for me

>> Is this the reason for Audi going on to the haldex system and
>> its computer control - the unpredictable nature of the torsen
>> when at the limits of performance?

> There are two reasons:
> a) Torsens are expensive mechanical devices.  Failure in the
> field means replacement - they cannot be rebuilt except by the
> factory.
> b) Many aspects of vehicle performance are now electronically
> controlled. An electronic device can be integrated much more
> easily.

Umm, I thought the whole Haldex thing was just a way to put
"quattro" (synchro, really) in the smaller cars that won't take
longitudinal engines--an evolution of the VC synchro system
essentially. The Torsen is still alive and well, but I've been
wondering if Audi will ever evolve EDL into a cross-axle system.
It seems to me the major costs would be in the development of
the software. Three open diffs and a few more chips would be
very cost effective, methinks.