[s-cars] Weird boost issue

Theodore Chen tedebearp at yahoo.com
Mon Nov 28 18:35:01 EST 2005 

thanks, but mine is metal.  only the '95-later UrS6 got
plastic, i think.

-teddy

--- Aaron Taylor <atay at cox.net> wrote:

> Im assuming you guys don't have plastic crossover tubes.  If so, they crack
> at the mounting tabs.
> Aaron
> 
> -----Original Message-----
> From: s-car-list-bounces at audifans.com
> [mailto:s-car-list-bounces at audifans.com] On Behalf Of Theodore Chen
> Sent: Monday, November 28, 2005 3:59 PM
> To: Robert Myers; chris chambers; Scar
> Subject: Re: [s-cars] Weird boost issue
> 
> i'm following this with interest, as i seem to have the same
> problem.  my car is a '92 with MTM stage II+.  boost is
> inconsistent, sometimes peaking at an indicated 1.0-1.2 bar
> on the digital boost gauge (this gauge likely reads a bit
> low because the MTM stage II+ kit changes the pressure
> transducer from 2.5 bar to 3.0 bar).  other times, i get
> full boost (indicated 2.0-2.1 bar).  sometimes this happens
> during the same acceleration run.  first i get weak boost,
> and then all of a sudden it kicks in with full boost.  i
> cannot reliably replicate this.  engine starts and runs 
> smoothly.
> 
> i installed a forge bypass valve several years ago.  the
> intercooler-TB hose is a samco.  i just replaced the
> crossover-intercooler hose with a samco.  i'm not sure if 
> the crossover hose was stock - it's some kind of black fabric
> with reinforcing rings on it.  it seems to be in decent shape
> but i replaced it with the samco anyway.  the turbo-crossover 
> hose is orange and seems to be made of a similar material, and
> i believe this piece is from hoppen.  i have a samco hose to
> replace it but haven't done that yet.  the u-bend hose from
> the turbo-crossover hose to the bypass valve is rubber.
> 
> efforts so far: i replaced the clamps on both sides of the
> moisture trap, swapped in the samco crossover-IC hose, and
> tightened various clamps.  the lower clamp on the 
> turbo-crossover hose snapped off when i tried to tighten
> it.  it may have been broken already.  i replaced it with
> another gear clamp.
> 
> where else should i be checking?  considering the symptoms
> that the car is showing (going from low to full boost in
> the same acceleration run), i'm inclined to think it's a
> boost sensing/control problem rather than a boost leak in
> the intake path.  what do you think?
> 
> -teddy
> 
> --- Robert Myers <Bob at chips-ur-s.com> wrote:
> 
> > 
> > I have three ECUs each with a 3 bar Pressure Transducer of one form 
> > or another.  One with a Bosch 3 bar PT and two with VMAPs.  I have 
> > been inside all three within the last two days.  They are 
> > OK.  Changing one ECU for another does not have any effect on the problem.
> > 
> > My boost gauge registers something on the order of 0.5 atm vacuum at 
> > idle and responds to changing manifold pressure.  At present te 
> > maximum observed boost si on the order of 6 to 8 psi.  There is an 
> > approximate 20 psi missing.
> > 
> > I'm tempted to whack the wastegate with a BFH to see if I can jar 
> > anything loose.  Hmmmm...  Possible Forge BPV acting up?
> > 
> > At 10:57 AM 11/28/2005, chris chambers wrote:
> > 
> > >*This message was transferred with a trial version of CommuniGate(tm)
> Pro*
> > >damn too bad....
> > >
> > >My thoughts are more towards boost sensing not loss of boost.
> > >If you rule out a leak at the trap, I'd check the lines to the
> > >ecu and maybe the VMAP, do have a VMAP right?
> > >
> > >Your Boost gauge doesn't indicate a loss of boost does it?
> > >
> > >
> > >
> > >--- Robert Myers <robert at s-cars.org> wrote:
> > >
> > > >
> > > >
> > > > I wish...  :-(
> > > >
> > > > The water trap hoses are in excellent condition and the system hold
> > > > pressure so I'm convinced that this is not the problem.  Gotta admit,
> > > >
> > > > though, that that was my first item to check.
> > > >
> > > > At 10:35 AM 11/28/2005, chris chambers wrote:
> > > >
> > > > >Bob,
> > > > >
> > > > >I had the same problem earlier this summer.
> > > > >
> > > > >After ALOT of searching finally figured out the water trap hose
> > > > >somehow got deformed and even though I would clamp down tight it
> > > > >wasn't sealing completely. I shortened the hose removing the
> > > > >deformed end and reattached it to the water trap, problem fixed.
> > > > >
> > > > >Hope yours is as easy to fix as mine.
> > > > >
> > > > >
> > > > >HTH
> > > > >Chris
> > > > >
> > > > >
> > > > >
> > > > >Make April 15th just another day http://www.fairtax.org
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >__________________________________
> > > > >Yahoo! Mail - PC Magazine Editors' Choice 2005
> > > > >http://mail.yahoo.com
> > > > >_______________________________________________
> > > > >S-CAR-List mailing list
> > > > >S-CAR-List at audifans.com
> > > > >http://www.audifans.com/mailman/listinfo/s-car-list
> > > > >
> > > > >
> > > > >
> > > > >-- incoming mail is certified Virus Free.
> > > > >Checked by AVG Anti-Virus.
> > > > >Version: 7.0.362 / Virus Database: 267 - Release Date: 11/28/2005
> > > >
> > >
> > >
> > >Make April 15th just another day http://www.fairtax.org
> > >
> > >
> > >
> > >
> > >__________________________________
> > >Yahoo! Music Unlimited
> > >Access over 1 million songs. Try it free.
> > >http://music.yahoo.com/unlimited/
> > >_______________________________________________
> > >S-CAR-List mailing list
> > >S-CAR-List at audifans.com
> > >http://www.audifans.com/mailman/listinfo/s-car-list
> > >
> > >
> > >
> > >-- incoming mail is certified Virus Free.
> > >Checked by AVG Anti-Virus.
> > >Version: 7.0.362 / Virus Database: 267 - Release Date: 11/28/2005
> > 
> > 
> > Bob
> > Http://Chips-Ur-S.com
> > _______________________________________________
> > S-CAR-List mailing list
> > S-CAR-List at audifans.com
> > http://www.audifans.com/mailman/listinfo/s-car-list
> > 
> 
> 
> 
> 		
> __________________________________ 
> Yahoo! Music Unlimited 
> Access over 1 million songs. Try it free. 
> http://music.yahoo.com/unlimited/
> _______________________________________________
> S-CAR-List mailing list
> S-CAR-List at audifans.com
> http://www.audifans.com/mailman/listinfo/s-car-list
> 
> 



		
__________________________________ 
Yahoo! Music Unlimited 
Access over 1 million songs. Try it free. 
http://music.yahoo.com/unlimited/

More information about the S-CAR-List mailing list