bypass valve

[JShadzi at aol.com]

   Hey Todd, I noticed that too at the show, but that is not how the cars were run in actual race trim.  The true IMSA/GTO bypass valve was actually an EGR valve that Audi Sport modified, and consequently, made the wonderful, trademark turbo chirp as heard in the TransAM cars too.  Those stock vavles would not last 5 minutes out on the track, especially at the ungodly boost and CFM levels run on those cars.
Javad

<< FWIW,
  Down at the Monterey Historics, we saw the hood get popped on
the IMSA 200.  Or was it the Trans Am 90 GTO.  Either way, point
is, it had a factory Bosch bypass valve.  Maybe only because at
the time nothing better was available and they changed it at
every pit stop.  I dont know.  But it was there. Heh Heh. 
  That said, a friend just put a Forge Valve and then a Baily
Valve on his ur-S4.  Both gave noticable better and more
consistent boost.  Even on a Brand new TT they made a small
difference. Enough so that they both bought one. :-)
l8r
  Todd

--- Peter Berrevoets <pjberr at home.com> wrote:
> 
> I see your point in the potential for failure in the diaphram
> of this bosch
> unit.
> 
> However, several performance tuners and most notably Dahlback
> Racing in
> their gazillion HP 20V Turbo motor are using this valve. The
> Dahlback in
> fact uses two in parallel and uses quite a bit of custom
> fabrication to do
> so.
> 
> Perhaps there is some merit to using the Bosch valve. I know
> they make good
> products, is it perhaps the method of deployment that is in
> need of
> modifying rather than blaming the valve itself?
> 
> my $0.02
> 
> Peter Berrevoets
> 1990 200TQ
> Toronto, Canada


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