[BiturboS4] boost pressure decreasing...

[California Fields]

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I've noticed that my peak boost is no longer around 16-17 psi as was the case
when I first installed my GIAC-X and boost gauge.  The peak boost now reaches
about 15psi, and that's usually only when I floor it in a tall gear (5th or
6th) at lower rpms (2,500-3,500rpms).  When I really rev it up (>4500rpms), it
is more around 12-14psi...whereas before it seemed to hover right around 15psi
until above 5500rpm when it would taper off slowly.

Could this mean that I have a boost leak somewhere? Or, could this be a sign
that the turbos are going?  I haven't really noticed any other symptoms except
*maybe* a slightly louder turbo siren whine (but hard to say).  No DTCs
detected by VAG-COM.
Any input helpful. Thanks.
------------------------------
Carter Fields, San Francisco
2001.5, GIAC-X, Miltek 3" cat-back, Strat. shifter, Strat. DVs, A-pillar boost
gauge
------------------------------
>From: Matt twentyV
>To: BiturboS4 at audifans.com
>Subject: [BiturboS4] V8 Tuning Potential
>Date: Fri, 31 Jan 2003 14:16:08 -0800 (PST)
>
>So we've had this debate now about whether the V8 S4
>could be tuned to 400hp. So I went to look at
>tuning options for BMW- which like the upcoming S4,
>uses highly tuned NA engines out the door.
>
>In a nutshell, forget it unless you add a
>supercharger.
>
>For the E36 M3, you can find exhaust and chip
>combinations that have dyno data showing 10-15hp
>increases. There are also a few supercharger kits
>out there that advertise 80hp or so at 8psi.. $6k.
>
>For the E46, some tuners claim 7-8hp increase but
>don't show dyno graphs. I found one supercharger
>kit for the E46 330i
>(http://www.activeautowerke.com/Supercharged/E46-330isupercharger.asp).
> For the E46 M3, there is
>some message board activity indicating AC Schnitzer
>is developing a system that will reach 400hp... for
>$13k!! I'm guessing that involves an entire rebuild
>to use new pistons to reduce the 11.5:1 CR. As
>someone already mentioned, adding boost to an engine
>at that high a CR is problematic.
>
>Matt Rooke
>'91cq- 20vt chipped
>'00S4- 30vtt stock
>
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