re: adjustable boost for your turbo audi

[pjrose@servtech.com (Phil & Judy Rose)]

>>Date: Sat, 29 Aug 1998 21:51:28 -0400
>>From: RABE <brabe@snet.net>
>>Subject: adjustable boost for your turbo audi
>>
>>I found an easy way to make your boost adjustable on a turbo audi.  Go
>>buy an adjustable air pressure regulator (i got mine at sears) get it as
>>close to 0-25 lbs as you can but you can use a big one too ( mine goes
>>to 125 psi.  Take the hose off the back of the wastegate run a line into
>>the car.  Run another line off the tee out of the manifold that sees
>>pressure.  run the pressure through the regulator onto the back of the
>>wastegate.  open the pressure regulator a little bit, like an eighth
>>turn and drive the car.  Keep an eye on the boost.  If you want more
>>turn it slowly till you get it where you want it.  Be careful not to go
>>too high.  TAP told me the stock computer on a 5kt is programed to 9psi.
>>If you want to RE: send it to j-yr-be@snet.net
>>                                                Jay


This boost mod sounds similar to one I saw described recently for the dorF
Probe GT. In that case, the entire wastegate frequency valve was eliminated
and replaced by a "T" fitting which carried a bleeder valve to the car's
interior. For higher-than stock-boost, the instructions were to open the
valve a bit, but not enough to induce fuel cut-off by the ECU. Increased
boost by up to 6 psi was claimed (6 psi max is stock, and the ECU shuts off
fuel at 11.99 psi).

Jay retains the frequency valve, but limits its maximum effect with the
regulator valve. Something along similar lines was posted on the Qlist a
week or so ago, and I'm surprised no comments were forthcoming. What are
the hazards involved in these approaches? Any timing issues? Is it
applicable to the 3B engine?

Phil Rose
'91 200q
'89 100 (112K, automatic, for sale)
'89 Probe GT

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