GTM stage 1 S/C - Throttle not opening fully? Or boost leak? Please help!

fillerbunnie

So more than 2 years after installing a GTM stage 1 S/C, I still am plagued by gremlins.

Basically, cold start performance is excellent. I get on-boost instantly and it pulls like a maniac. After it is fully warmed up, I get consistently poor (slower than stock) performance, with intermittent full-power.

I have spent days and days chasing boost leaks that simply don't appear to be there. Everything is double-hose-clamped and holds 15psi on a pressure test with no leaks to be found...

I've attached some screenshots of uprev logs showing two runs in second gear, performed about 15 seconds apart. In run 1 (good run), which is ~2800 to 4000 RPM, I instantly get boost, which rapidly builds to ~5psi by 4000rpm. Power delivery is excellent, timing advance sits at about 15 degrees during WOT and the throttle & VVEL exactly match my accelerator input.

The second run, performed literally 10 seconds later, with WOT from ~2800 to 4000rpm, exactly as in the good run. The car sits at 0psi, then builds to maybe 1psi by 4000rpm. Performance is horrific. Timing sits at ~22 degrees, and the throttle and VVEL seem to slowly work their way open rather than matching the accelerator pedal input.

I have played with the throttle maps for hours, and I simply don't understand how WOT at the same RPM, in the same gear, performed 10 seconds later, can have a completely different response! I assume if this was an (impossible to find) boost leak I would get the VVEL & Throttle performing the same way in both runs?

It's like there is some other feature/sensor/something that is wildly changing the car's throttle response, even on identical runs.

I'm so sick of battling this gremlin, and it is really sapping any fun out of the car Any advice would be greatly, GREATLY appreciated!!!!!

Thanks

Attached Images

	Good Run.png (23.5 KB, 30 views)
	Bad Run.png (20.8 KB, 23 views)