Right, a handful of photos from tonights endeavour.
Arrived at my friends house to fit the GFB DV+, r8 Coilpacks, and replacement of the Cam Follower.
He's a bit of a dab hand with a spanner. One of his rally school Impreza's up on stands next to the trusty Golf. I realised he also has enough spare parts dotted around to build another Mk2 Escort.
First up was the Diverter Valve
Do not underestimate this clip on the back with the sensor. It took far too long (like, an hour) to get the thing to come off. I would invest in the right tool to do it, mine appeared to be jammed on.
Rebuilding the DV with the GFB parts was painless, and on that went.
I was pretty confident the issue I had with boost was the DV, but I'd been recommended to swap out the coil packs for the R8 type, and the Cam Follower.
The cam follower.... the banjo bolt that holds on one of the fuel pipes into the fuel pump was a bit of a beast to get to - fiddly. I'd recommend a ratchet spanner that has pop in Allen/hex/torx/etc parts to make your life easy.
So, did this work?
Yes. It feels much better, which makes me thing the DV was on the way out before my remap. The car now has a very deliberate 'sclurp' noise from 1500 ish to 2750 ish RPM. The car feels really smooth and responsive now. Highly recommend this maintenance.