[Biturbos4] Wheel spin - Thread Hijack - Wheel Spin

[j y]

With the current thread - I guess we've found some more marketing hype about Quattro versus fact. Anyway, my tech found out something very interesting about the Quattro system on S4s when he removed my driveshaft. Going under the assumption that a true AWD car will still provide power to the front wheels when the driveshaft has been removed, my tech found out that this is not possible in the S4. No, in my tech's observation, the Quattro system on the S4 is rear wheel biased. If the driveshaft connecting the front and rear wheels is removed, then there will be no power transfer from the rear to front wheels, and the S4 will not operate like FWD car (as he expected), with the connecting driveshaft removed . He observed this with his own eyes. According to my tech, the S4 is not a true (fulltime) AWD car. Might help explain why the original poster could not move forward when his real wheel stuck. 

Quincy Chiang <b5quattro at shaw.ca> wrote:EDL is part of the quattro IV system, whether you have ESP or not. Like Keman said it's a reactionary system, it uses ABS wheel sensors to sence wheel spin. It brakes the spinning wheel (with no/low grip) to in effect fool the open diff to thinking that the other side (which has more grip) is slipping in relative terms, so that the open would automatically send power to that wheel. Clever, but it's no where close to actual LSDs in terms of effectiveness.

When quattro IV came out, Audi advertised that this new system is the first that can keep going with 3 wheels slipping. Obviously you successfully foiled their claim!

Quincy

----- Original Message -----
From: northrup 
Date: Wednesday, April 13, 2005 9:21 am
Subject: Re: [Biturbos4] Wheel spin.

> if you have ESP, I'd imagine that the "brake pressure" will be 
> automatically applied for you.... at least that's how it works in 
> non-audi 
> cars. 
> 
> As for me, i applied the brake pressure as Keman mentioned to get 
> going. 
> It worked - but i was disapponted to note the open differential 
> setup. 
> 
> I installed a Quaife LSD in a previous front wheel drive vehicle, 
> that 
> directed power to the wheel that had traction - it was quite a 
> nice 
> addition.
> 
> On Wed, 13 Apr 2005, Single Malt wrote:
> 
> > Does this apply to B5 models with ESP as well (does
> > ESP imply EDL)?
> > 
> > --- Keman wrote:
> > 
> > > The front and rear differentials are open, all you
> > > had working in your
> > > favor was the torsen center differential, since
> > > there was more torque
> > > required to spin the front wheels than the rear, and
> > > the torsen will
> > > multiply torque to that the side with the most
> > > resistance.
> > > 
> > > The problem is, anything times zero, is still zero.
> > 
> > 
> > --
> > Single Malt
> > '01.5 S4
> > Garaged at 9200ft
> > just outside Denver, CO
> > 
> > 
> > 
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