Guess that problem: Round 1 (have I killed it?)
 

Gents, just spent the best part of two days swapping an old y-pipe for the later spec one (the small straight hose in the middle of the y-pipe was leaking oil, which in turnw as dripping onto the hot turbopack :icon_tdow). While I'm at it I removed the air pump and fitted my SuperNow Response Up (blanking plate) kit. I got it back together, up and running fine, took it for a drive, gently at first. Stopped, popped the bonnet and checked everything again. Started increasing throttle inputs, seemed to be find, boosting upto .79 bar fine, kept an aye on the Apexi PCF Commander. All seems fine.

Then, I came off a roundabout, accelerated up behind a lorry as we rounded a shallow bend. Road ahead was clear, dropped it down a gear, accelerated in 2nd, into third, it revved quite high and then pop, pop pop pop missfires... I backed off and disengaged the clutch and it started to idle rough. Pulled over and called my fellow petrolheads Matt and Dammit, who came out to console me.

So - we decided to limp it a mile or so back to mine and do a poor mans compression test. Here are the results:

Front housing video

Rear housing video

Boost gauge at idle.

You can hear a consistent pattern in the compression 'tsch' 'tsch' 'tsch', we expected 'tsch' 'tsch' nothing, 'tsch' tsch' nothing. You can also hear that the front sounds different from the back housing. I've included a video of the boost guage fluctuating at idle.

I'd appreciate any advice/thoughts at what the problem could be, and anything to try to try and put my finger on it. I've got my fingers crossed that it could be a leak somewhere where I've perhaps not tightened properly or a gasket gone on a blanking plate or something. I'm expecting the worst though :(