[s-cars] Question about turbo chatter and BPV

[James Bufkin]

I don't own a urS4, but a good friend of mine does and I helped him install 
a Stage 1 pair of chips yesterday morning.  The chip install went fine and 
the 287 HP was definnately there, but when I sat in his car and we went for 
a test drive, I was hearing a definate turbo chatter at the top of the revs 
between shifts.   I could especially hear it when driving next to parked 
cars or concrete barriers.

I told him I think his BPV is faulty cause that noise is indicative of 
turbo stall, just like the rally cars used to make (I really like the 
sound, but its not good for a street car in the long scheme).   He said his 
car has been making that noise for a year or so.   Good thing the guy 
rarely takes his car about 4K rpm when he's driving...     So we went back 
to my place and removed the BPV, It looked okay.   There was a trace of oil 
on the side facing the turbo, which was odd, but could be explained by the 
fact we were pushing the motor to test the chip.   The vacuum line to the 
Valve was intact as well.

Is the only possibility a torn boot inside the BPV?

James



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James Bufkin, P.E.
Bufkin Design & Engineering, Inc.
Austin, Texas
ph: 512-236-8070
fax:  512-480-5927
cell:  512-914-2659