Gents - since an aborted attempt to replace my AST with a metal one, I'm having a few boost issues. The cars on stock twins, Apexi filters, Apexi ECU, decated exhaust. I put everything back together and it wont boost past 0.4bar. It pulls as rapidly as it did before, but as soon as it gets to 0.4bar you can feel the power tailing off. I understand the second turbo wont spool up properly if the first hasnt. Its feels like it's revving fine though.

I've taken the boost pipework apart and put it back together again, checking for cracks and loose connections, but all seems to be fine. I plan on doing the KOKO test from here after finding a few threads recommending it on here and other forums, but before I do, has anyone else experienced this on stock twins?

I just want to get it back and working again for the summer - I plan on taking it off the road and going single this winter!

 

Someone on another forum has suggested that 0.4bar is just wastegate pressure - can anyone confirm this? If so it might just be a pipe popped off in the rats nest...