Inconsistent boost

[Marky]

I have a 97 GTB

It is running just fine, and 90% of the time does a pretty consistent 15psi (ish, the gauge cost me $5) on either primary or both.

Problem is the 10% of the time it doesn't want to, it decides to just run about 8 or 9 psi on primary and then 15 on secondary.

Car has factory downpipes and 3" from Y pipe back, pod filter, and I've already tried de gunking everything with some upper engine cleaner (which for the record is a fricken miracle product).

Is it just the ECU pulling boost back, or would it be the factory BCS sticking closed now & then? Tonight put foot down in third, sat on 9psi for a second or two (I mean quite steady), jumped to 15 for a bit, then VOD time so it's hard to repeat the problem.

Solution is easy (relief valve time) but something in me just likes the idea of leaving it ECU controlled haha

[Swindog]

it should run 9-11 on primary and 14-15 on secondary.

[Guest]

With a larger exhaust and cool nights you might find that you are boosting a bit higher though.

[WRXONP]

did u clean the solenoid ? properly?

but yeah i allways thought it was around 11 then 15 - but ive never had a TT before

[Guest]

What solinoid do you clean?

[94 Leone]

The dirty one.

[Guest]

 94 Leone said:

The dirty one.

lolz true

[Marky]

Thought I had cleaned it out (engine clean then CRC up the hoses, seemed to fix it), super intermittently it kept being a munter though. Don't think it was ecu pulling boost back at all purely cause it would sit on 9-10psi and just rando jump up to 15ish halfway through a gear

Went with the solution of removing it from the equation, just running 14psi on primary and secondary via a relief valve now, comes on boost way faster now and much "smoother" I guess, shortens the VOD a bit too which can't be a bad thing. Toyed with the using a hobbs switch or something and a spare solenoid I had in the garage but this way works just as well and I'm too lazy to stuff around any more

Jaseandjess - the factory boost control solenoid is tucked away inside the passenger's guard I think, hose 23 feeds to it and it then vents through hose 10 back the other way. You can trace it from the WG tee-off, up behind the battery and into the wing somewhere.

[Guest]

Cheers marky. I know the hoses. Should I just spray some upper engine cleaner up there or some crc?