[s-cars] By-pass valves

Sat Sep 18 09:25:54 PDT 2010

May I suggest the BPV from a Saab 9-5 Aero. These are the same valves that
MTM use. It's sometimes called the Bosch 110 Valve
http://www.hoppenmotorsport.com/BoschBypass.htm

On Thu, Aug 12, 2010 at 8:42 PM, Tony Curran <tony.curran at sympatico.ca>wrote:

> Bypass valve analysis from S4 group...
>
> http://www.s4biturbo.com/art-dvtests.php
>
> http://www.s4biturbo.com/art-dvtests2.php
>
> Tony
> 96 S6 with 034 bypass valve.
>
> -----Original Message-----
> From: s-car-list-bounces at audifans.com
> [mailto:s-car-list-bounces at audifans.com] On Behalf Of dgraber460 at aol.com
> Sent: August 12, 2010 3:51 PM
> To: captmagu at gmail.com
> Cc: quattro at audifans.com; benswann at verizon.net; s-car-list at audifans.com
> Subject: Re: [s-cars] By-pass valves
>
> Oh Yeah, now I remember reading that on the stall door at the truck stop.
>
>
> Dennis
> Denver
>
>
>
> -----Original Message-----
> From: Hap Maguire <captmagu at gmail.com>
> To: DGraber460 at aol.com
> Cc: qshipq at aol.com; djdawson2 at aol.com; benswann at verizon.net;
> esanborn at gmail.com; quattro at audifans.com; s-car-list at audifans.com
> Sent: Thu, Aug 12, 2010 10:23 am
> Subject: Re: [s-cars] By-pass valves
>
>
> Hey Dennis
> I've seen Dave Jones test a bypass valve by sucking on it. He is called
> Tufty
> or a very good reason.
> Hap, wit dakine Tuftyism not from Evahboost, Maguire
>
> n Aug 12, 2010, at 4:10 AM, DGraber460 at aol.com wrote:
> >
>  Thanks Scott, Dave, et al;
>  I understand the Bosch Audi OEM's operation pretty well as described by
> Dave
> nd Scott.
>  Having said that, my question was, and is, should the OEM plastic valves
> open
> n the bench with vacuum applied to the small control port? The Forge
> aluminum
> alve does, but neither of my OEM plastic units will, and I hear what seems
> to
> e air bleeding by the diaphragm when vacuum is applied.
>  They have never (at least in my ownership) been installed backwards, but
> ondering if they need to replaced and tossed, or if they are as normal for
> a
>
> tock OEM. I'm guessing from this behavior that the diaphragm is ruptured
> and
>
> hey are toast?
>  TIA
>
>  Dennis
>  Denver
>
>
>
>  -----Original Message-----
>  From: qshipq at aol.com
>  To: djdawson2 at aol.com; benswann at verizon.net; esanborn at gmail.com;
> graber460 at aol.com
>  Cc: s-car-list at audifans.com; quattro at audifans.com
>  Sent: Thu, Aug 12, 2010 7:36 am
>  Subject: Re: [s-cars] By-pass valves
>
>
>
>
>  Agree, many are mixing bypass valve operation with blow off valve.  I have
> not
> een any bypass valve that boost helps 'blow open' from below.  Most (all
> audi
> pps) are oriented as DJD explains with the boost 90degrees to the diaphram.
>
> he HKS sequensial bypass valve is oriented with the diaphram in line with
> the
> oost pressure.  However, it's operation is spring adjusted and operates as
> a
>
> tepped  'needle valve', so it's still the feed line on the device that
> dictates
> alve opening and close.
>
>  A blow off valve oriented with the diaphram in line with boost pressure,
> has
> o intake feed, it is an absolute boost pressure device that pops when the
> boost
> n the intake manifold exceeds a set pressure.
>
>  Scott J
>
>
>  -----Original Message-----
>  From: djdawson2 at aol.com
>  To: benswann at verizon.net; esanborn at gmail.com; dgraber460 at aol.com
>  Cc: s-car-list at audifans.com; quattro at audifans.com
>  Sent: Wed, Aug 11, 2010 11:20 pm
>  Subject: Re: [s-cars] By-pass valves
>
>
>
>
>  Mixing terms... and what you're saying isn't really accurate.
>
>
>  The valve, is normally closed.  Apply a vacuum and it opens.  Apply boost
> and
> t
>
>  remains closed.  The signal comes from the intake manifold.  The intake
> anifold
>
>  in a naturally aspirated engine is always in some state of vacuum.  This
> means
> >
>  that if you are not making any boost, there will be a vacuum in the
> intake...
>
>  inclining the BPV towards opening.
>
>
>  Positive manifold pressure will NOT  "assist to force or blow the valve
> open
>
>  when vacuum is applied to the control port" because those 2 things can't
> ever
>
>  happen at the same time.  If there is pressure in the intake, there is
> ressure
>
>  forcing the BPV to remain closed.  When there is vacuum in the intake,
> there
> s
>
>  vacuum at the BPV opening it up.  Furthermore, boost hits the *side* of
> the
>
>
>  piston (Forge) or diaphragm (Bosch)... never able to assist in opening the
>
>  valve, unless you have it improperly installed.
>
>
>  If as stock BPV is installed backwards, you will blow the diaphragm in
> short
>
>  order... it's just rubber, and it won't last long fighting 20+ psi.
>
>
>  The BPV's purpose is to alleviate pressure stall in the intake plumbing
> (and
>
>  therefore the turbo) when the throttle closes.
>
>
>  Anyway....
>
>
>
>
>
>
>
>
>  -----Original Message-----
>
>  From: Ben Swann <benswann at verizon.net>
>
>  To: esanborn at gmail.com; dgraber460 at aol.com
>
>  Cc: 'Quattro List' <quattro at audifans.com>; s-car-list at audifans.com
>
>  Sent: Wed, Aug 11, 2010 6:51 pm
>
>  Subject: Re: [s-cars] By-pass valves
>
>
>
>  No, just the opposite.  The Bypass valve is normally closed.  The control
> port
> >
>
>  is vacuum
>
>
>  actuated and tends to open the valve.  Positive manifold pressure will
> assist
> o
>
>
>
>  force
>
>
>  or blow the valve open when vacuum is applied to the control port.  This
> appens
>
>
>
>  only
>
>
>  when the throttle valve snaps shut while engine is under positive pressure
> -
>
>
>  like
>
>
>  between shifts.
>
>
>
>
>  So the mityvac test is not necessarily going to tell you if the valve is
> pening
>
>
>  properly and some valves have beefier springs for higher boost pressure.
>
>
>
>
>  Also, if the valve is installed backwards then it may not open or flutter
> when
> >
>
>  opening,
>
>
>  or open when it should not open.  Funny thing is the way most valve are
>
>
>  oriented, the
>
>
>  correct way does not look correct.  You  might want to verify that the
> irection
>
>
>
>  of the
>
>
>  valve is correct.
>
>
>
>
>  See: http://www.gtquattro.com/Bypass-Valve.html that has a picture of how
> the
>
>
>  valve is
>
>
>  connected/oriented.
>
>
>
>
>  Ben
>
>
>
>
>  [Date: Wed, 11 Aug 2010 17:56:43 -0400
>
>
>  From: Eric Sanborn <esanborn at gmail.com>
>
>
>  Subject: Re: By-pass valves
>
>
>  To: dgraber460 at aol.com
>
>
>  Cc: s-car-list at audifans.com, quattro at audifans.com
>
>
>  Message-ID:
>
>
>    <AANLkTin-vkgjJaotOtbbX3ToE1Ab-yLvLzkJ2293n-xq at mail.gmail.com>
>
>
>  Content-Type: text/plain; charset=ISO-8859-1
>
>
>
>
>  I might be misunderstanding what you were testing, but they should only
> open
>
>
>  during boost.
>
>
>
>
>  On Aug 11, 2010 5:12 PM, <dgraber460 at aol.com> wrote:
>
>
>
>
>  List-et-al;
>
>
>  I have been chasing a full throttle issue on my 3B'd URQ for a few months
>
>
>  now. The symptoms have been a flattening and lack of power under full
>
>
>  throttle. My boost gauge has always shown full boost at 19-20, and it
> throws
>
>
>  no codes. I started to notice the moaning (not whooshing) noise when off
>
>
>  throttle, which I had heard before and found to be an aluminum bypass
> valve
>
>
>  that needed cleaning.
>
>
>  Since it had been running an OEM Bosch plastic valve, I pulled the Forge
>
>
>  valve off the S-Car and cleaned it up and installed it. On the drive this
> AM
>
>
>  it seems to have cured the issue. Time will tell if total cure.
>
>
>  The question I have is that I tried to test all 3 valves that I have while
>
>
>  messing around last night. I have 2 plastic, and 1 Forge valve. I hooked
> up
>
>
>  a vacuum pump that pulls 14 lb hg to each valve individually and _none_ of
>
>
>  them would pull open. Then I used my little Mighty Vac hand pump and the
>
>
>  Forge valve would pull open and stay. Neither plastic OEM valve would open
>
>
>  with either test. Does this indicate both OEMs are toast?
>
>
>  I assume the vacuum pump did not have a check valve and therefore could
> not
>
>
>  "build" vacuum as the Mighty Vac did, thus letting the valves flutter but
>
>
>  not pull open. Sound reasoning?
>
>
>  Also - is there a recommended lubricant that keeps the aluminum valves
>
>
>  happy, and functional, or should they remain dry?
>
>
>
>
>  Dennis
>
>
>  Denver
>
>
>  ]
>
>
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-- 
Jared Robinson