Boost loss?? (after MC rebuild/upgrade & T3/K26 turbo)

[Jim Green]

--- Ben Swann <bswann at worldnet.att.net> wrote:
> On Thursday, June 13, 2002 2:01 AM, Rick Houck
> [SMTP:rhouck at neo.rr.com]
> wrote:
> > Ben,
> >
> > I have a 10v turbo engine that I rebuilt to
> install in my 1990 coupe
> > quattro, and I have had some teething pains as
> well. I am now reliably
> > running 20 PSI of boost (over atmospheric
> pressure), which may be 2.3
> bar,
> > depending how you look at it.
> >
> > It takes only a small crack opening up somewhere
> to bleed off pressure. I
> > have popped just about every fitting at one time
> or another, so I would
> see
> > if you can do some kind of pressure check to find
> the problem. Don't
> forget
> > to check the boost gauge line and even the
> original hose into the ECU.
> Also
> > check the intercooler joints to see if they may be
> expanding and leaking.
> >
> > Good luck.
> >
> > Rick Houck
> > Ohio
>
> Ok thanks for the suggestions.  I have been over all
> of this, been looking
> for over 2 months now before finally consulting this
> list.  I have not been
> able to identify any possible leaks in the intake,
> iIC's was strapped
> already.  I am seeing a solid 18-20 vacuem on my
> guage at idle.  I am
> pretty sure the system is tight.  I keep looking.
>
> Right now my biggest suspect(s) are:
> 1) The T3/K26 turbo just won't produce the boost.  I
> have been assured this
> is not the case, but this is the major change in the
> system.  Well I did
> open the exhaust, a tad,  but I wouldn't think that
> would reduce boost so
> much, although the upgrades followed the premise of
> less boost with more
> flow = greater power.
>
> 2) The wastegate is stuck slightly open - possibly a
> piece of debris got in
> there somehow.  I don't see how to verify this
> without removal.  Based on
> my experience re-installing with manifold etc.,
> wastegate removal is
> something that I don't want to get into unless I am
> confident the problem
> is there.  It doesn't completely make sense that
> this would be the problem
> either, since boost spools up incredibly fast, which
> wouldn't be likely if
> the wastegate were open.  Perhaps there is some easy
> way to disassemble the
> wastegate from the top, at least easier than the
> contortions required to
> remove it.
>
> I thought I'd get more feedback on this, but it must
> have been lost in the
> heated theoretical discussion I referred to earlier.
>  I thought my problem
> was relevant, as the T3/K26 is supposedly very
> similar to the RS2 turbo.
>  Now I am not convinced I made the correct decision
> in my selection.

Don't get discouraged, I think you'll like the turbo.
If you suspect the wastegate, take the cap off and try
moving the plunger up and down.  You may be able to
tell if it's sticking.  The only other thing I could
think of is a plugged exhaust system.
HTH,


=====
Jim Green
'89 90tq EFI
http://www.geocities.com/jeg1976/car_home.html

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