Car is MY98 UK turbo, just had new VF23 turbo fitted and Link ECU.

Boost pressures are fine in any gear below 5000 rpm and on any throttle.
On full throttle, in any gear, after 5000rpm, boost drops down 50%.
Can hold the boost to a slightly higher 5500 on half throttle, then it drops of again.

Tried cleaning boost hoses from solanoid.

Scoty

 

when the boost drops,does it just drop straight down or oscillate up and down before holding the lower,50% less value?

 

Just drops straight down, even with the dawes on it. The induction kit goes quiet as if it had stopped suckin in air.

The actuator is new also, but not rulling out a faulty spring in the actuator?

Just replaced the IC, but it still remains the same.

Scoty

 

Yes !! It's the Samco hose that's the culprit They are fine at standard boost (what they were designed for) but increase the boost and the high velocity inside the pipe creates a pressure reduction causing it to be pulled in.

Lots more fun in store for you once you fix it

Andy

 

Intercooler hosing being sucked closed? It has happened before, similar story.

[Edited by john banks - 6/8/2002 9:22:59 PM]

 

Sounds like turbo inlet induction hose collapse to me. Try a jubilee clip around the hose at the mid point as it will help support the edges from distorting which allows the hose to flatten out.

Andy

[Edited by Andy.F - 6/8/2002 9:40:02 PM]

 

Most hoses have been exchanged to Samco including turbo air intake.
Could this still happen even with the samco hose?

[Edited by Scoty - 6/8/2002 9:42:42 PM]