urquattro boost pressure

[Fluhr <ejfluhr@austin.ibm.com>]

Did I mention I have been indoctrinated into urquattro ownership, with
a perpetually sick car?  If I hadn't before, you know now...


The car was running great before and through some of the last track
event.  During one session, I noticed the boost pressure dropping
steadily each lap around the track.  I pulled off, and my brother and
I spent the rest of the day trying to figure out what happened.  The
intake hoses were OK, the turbo was OK, nothing seemed to be wrong
except for the screeching noise that developed above 7psi of boost
pressure.  After goofing with it for a few hours we, buttoned the
intake back together and went home.  Miraculously, the car was working
almost fine again, although I am still down ~2psi of boost pressure
over max before the track event.  The turbo appears in good shape,
with no radial or axial play at all.

Now, however, I have noticed something else.  The spool-up of the
turbo is less than it was before.  It used to hit around 5psi of
pressure @ ~2600rpms.  Now it reaches 3K before I see 5psi.  Max
boost pressure is still 13-14psi above ~3400rpms.

Any ideas?  At the track, the exhaust pipe cracked 3/4 of the way
around the back of the resonator.  At the time, I thought it was
due to an old exhuast system.  Now I wonder if I could have
excessive backpressure in the exhaust system that is causing my
slow spool-up.  Is this possible?

Thanks,
Eric
'85 CGT (the workhorse), '82 urq (the perpetual patient)
---
Eric J. Fluhr                                Email:  ejfluhr@austin.ibm.com
High End Processor Design                    Phone:  (512) 838-7589
IBM Server Group                             Austin, TX