[s-cars] Stromung Exhaust

[Tom Mullane]

Marc had mentioned this to me as well, but I took it mean installing a
bellows on the wastegate pipe to keep it from cracking off the side of the
main downpipe.  You are talking about a bellows at the base of the downpipe
where it meets the center/cat pipe, right?  If so, I would argue that this
is not needed; the factory system does not have one.

I also question whether or not a bellows would help at the WG pipe.  The
problem I see there with the current set up is that the factory bellows
between the WG and downpipe expands when the exhaust is pressurized and
tries to force the Stromung WG pipe toward the rear of the car and away from
the main downpipe.  A bellows here might exaggerate this effect unless it is
placed after the downward bend of this small pipe.  Perhaps the factory
bellows should be replaced with a shorter bellows that expands less?

Tom

Date: Tue, 7 Feb 2006 16:46:59 -0500
From: "Postupack, Jeff" <Jeff.Postupack at analog.com >
Subject: RE: [s-cars] Stromung Exhaust
To: "Taka Mizutani" <t44tqtro at gmail.com>
Cc: s-car-list at audifans.com, Kenneth Keith <auditude at gmail.com>
Message-ID:
       <8FDC0F9BE1F91D44BE964AA54AAA67B61A30C929 at wilmexm3.ad.analog.com>
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<snip>

Recently Marc Swanson offered the idea to integrate a flexible bellows
device at the Downpipe.
This reduces flex/stress at the DP due to the rearward steel moving
about.  Then I did the obvious thing
and checked out the new Audi S4, A4 at Audi Nashua and damn, that's
exactly what Audi
does.

So if I DO open the product improvement process, I'll try to address
both issues posted today.

All the best
Jeff