[s-cars] Bypass valve questions

[Steve Marinello]

There are plenty of opinions out there, and testing of valves, too.
Generally, they seem to show the stock and improved Bosch valves tend to
leak and that they're not real consistent.  My only comparison is this:  I
have an RS2 modified S6 avant with a stock valve.  I acquired an S6 sedan
with a Bailey valve as the only engine mod.  I have been repeatedly annoyed
by days, or particular runs during a day, when the avant just doesn't seem
to be making power.   Doesn't seem to be an issue with the Bailey, but
that's a stock engine.  Finally swapped them for a little while and, voila,
consistent power, if only for a few days.  Bailey back to the sedan,
Hyperboost on order from Stratmosphere.  Just wish I'd bought the damn thing
when they had their 20% off sale.

Also, one well known listers expensive repair/replacement of an RS2 turbo
that inhaled a failed Bosch valve makes me think I don't want to replace it
with another, even improved, stock valve.

But I really was going to go for the XS valve and just happened to pick up
the Stratmosphere catalog and decided it was time.  Done.  Over.  Can't wait
for it to get here...well, actually, I can, but you know how it goes.

Steve

----- Original Message -----
From: "Sean Douglas" <quattro20v at telus.net>
To: <Djdawson2 at aol.com>; <s-car-list at audifans.com>
Sent: Friday, June 20, 2003 9:18 PM
Subject: RE: [s-cars] Bypass valve questions


> Dave: Try this website - everything you wanted to know about BVs.
>
> http://dv.mistertam.com/
>
> Sean
>
> Sean Douglas
> 1997 Audi S6
> 1990 Audi 90Q20V
> Surrey, BC
> Canada
>
>
> -----Original Message-----
> From: s-car-list-admin at audifans.com
> [mailto:s-car-list-admin at audifans.com] On Behalf Of Djdawson2 at aol.com
> Sent: Friday, June 20, 2003 1:14 PM
> To: s-car-list at audifans.com
> Subject: [s-cars] Bypass valve questions
>
>
> --
> [ Picked text/plain from multipart/alternative ]
> All,
> I recently finished with engine upgrades (RS2 stuff).  Following the
> upgrades, I soon noticed the telltale mid-rpm moaning of a failed bypass
> valve. Looking around, I noticed Hoppen carried a version of the Bosch
> part... suffix of 110 (as opposed to 114 or 108).  There was a long
> story about 400 and 500hp MTM engines, and this bypass valve being a
> good solution.  I ordered away.  After installing the part, I could
> immediately notice the difference.  Huge lag between shifts, and what
> seemed to be a missing top end hit.  There isn't much to replacing a
> bypass valve... but I double checked.  All was OK (no, I didn't install
> it backwards).
>
> I removed the part.  I hooked up the small manifold port via a hose to
> some low pressure regulated air (10psi).  It was leaking away.  The
> diaphragm must be shot.  My original doesn't do this.  So then I hooked
> up air to the valve on the boost inlet port.  The original (108) starts
> to seep air at 19-20psi. The new (110) valve begins to seep air at
> 24-25psi.
>
> Well, I'm not going to bother with another Bosch unit.  It would be one
> thing if you got some reasonable service life from it, but what the
> heck?  Anyone have a suggestion about a good aftermarket alternative for
> our type of application (about24psi boost, in this instance)?  I'm not
> looking for anodized purple, or neon illuminated... just a bypass valve
> that is effective. TIA, Dave in CO
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