[BiturboS4] Blown turbos

[Ti Kan]

Edwards, Dave writes:
> I have read a number of posts from Americans about hearing a 'siren-like'
> noise, and some replies saying that its normal. All I can say is that over
> here we don't have any reports of such a noise. Just maybe there is a
> difference between US and Euro S4 which means the turbo is noisier for the
> US car, but I can't think why.

There is no difference between US and Euro S4 as far as the turbos
themselves go.  The number of reports of noisy US turbos is simply a
matter of a majority of S4s on these forums being in the US.  When you have
more people from one group, you're going to hear more from them, and
those with problems are going to be the most vocal.

I have a US S4 and the turbos are nice and quiet just as you described
in your previous post.  A little whistle that's audible with the window
open at low revs and quickly fades to inaudibility past 3K rpms or so.

> The S4 clutch should be fine for a stage I or II upgrade. Having said that
> with the reports of clutch problems on this list, maybe Audi has used a
> substandard part in the US model? I have not read any reports of early
> clutch failure on Euro S4s.

Here we go again.  No, there is no difference between US and Euro clutches.

Where there are differences between a US and a Euro spec car, it's
related to safety, emissions and other regulatory compliance, as well
as fuel quality and expected operating conditions.  Audi does not use
different parts between the US and Euro models in a gratuitous manner,
that would increase cost where it's unnecessary.

Another factor to ponder may be the driving style.  Many US drivers
like to go from stoplight to stoplight with jackrabbit start acceleration.
While the S4 could do that just fine, this amounts to clutch abuse
if the driver is ham-fisted (ham footed?).  Perhaps this might explain
the problems with the turbos and other intake system woes with all those
sudden spikes of boost and vacuum.  Where European city streets are often
narrow and crowded, the driving style would no doubt be quite different.
Where the S4 really shines in Europe is when it stretches its legs flat
out on the open highway.

-Ti
2003 A4 1.8T multitronic (soon)
2001 S4 2.7T
1984 5000S turbo
1980 4000 2.0
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