My scoob has developed a whistle when on boost, it is suddenly not accelerating as well as it should. It doesn't appear to be smoking, either under the bonnet or out of the exhaust. Any ideas?

 

Sounds like the dumpvalve may be leaking? Or a leak somewhere else?

 

That was my thought, but where is the dump valve on these blighters. 94 WRX

 

No idea, I've yet to find the bonnet release on mine
There will be a helpful person around in a minute I expect though

 

The dunmp valve on the MY94 Scoob sits to the front left of the intercooler. It's a very small unit (in comparison to later ones), and has tubes going to it from opposite sides (as well as a vacuum tube at the top) unlike the later ones which have one axial and one radial tube..

Find the intercooler, find the turbo. Look between them and you'll see the wee dump valve.

Of course it may be something else entirely... you could have an air leak somewhere else between the turbo and throttle body, or you could have lost a bit of pre-tension on the wastegate actuator. Either are easy enough to fix though

Hope this helps,

Pat.

 

A problem shared, I have a similar one, check all boost and vacuum pipework. Long tedious task I know. From my experience I have a small split in the plastic pipe from under the IC to the turbo. Done a temporary repair for now and it is a lot better. Also changed the seal between said pipe and IC, they do perish with age. I still have a little fall off of boost pressure but it is noticeably better. Good luck.

Dukey