[A4] Re: Quattro, Torsen, Haldex and others...

Gordie's Garage audidoodie at comcast.net
Mon Dec 27 17:51:34 EST 2004

Audi uses the EDL (electronic diff lock) to transfer power from side to side
in the Quattro IV.  It just uses the ABS sensors to apply slight brake tot
he wheel that is spinning (jus like any ole traction control system) thereby
providing power to the other wheel, so it can pull out with with grip at
only one wheel.  If you want to 'feel' the EDL, just find some glare ice,
stop and accelerate sufficiently to spin the wheels.  You can feel the
brakes from side to side as it tries to find a wheel with some grip.  You'll
spin all 4 wheels, albeit alternately.  With my old 86 4kq, I could spin 3
of 4 wheels simultaneously with the center and rear diffs locked.
Not sure I believe the 0-100% and 100%-0.  IIRC, when I worked at an Audi
dealer we learned a 70%-30% split either way (f-r & r-f) for automatics and
40-60 for the man trans.


> > This is interesting...
> > http://www.williamtoll.com/images/nytawd.jpg
> >
> > Check that out.  Notice "can one wheel drive car".
> > The demonstration I saw this was clearly not the case with a Quattro IV
> > equipped A4.  Now, given
> > that this was a marketting demonstration, it could have been rigged.
> > But just ask easily, Audi
> > could be overstating the facts.  I wonder. Hmm...
> That IS interesting, and it shows that VAG seems to have the most flexible
> AWD solution out there, being the only one(s) that can go from
> 0-100%/100-0% front/rear wheel torque split, along with driving only 1
> wheel. So what exactly are we debating?! ;-)
> Dan D
> '04 A4 1.8Tq MT-6
> Central NJ
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> A4 at audifans.com
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