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Discussion Starter #1 (Edited)
HELP!!! T78 wastegate boost leak

This is might be long but need to explain the full scenario.. sorry

The following is on my car: t78, vpc, gcc, profec-b, upgraded fuel, g-force ecu, blah, blah, blah.....

I was on the dyno on Wednesday 2/22: after numerous pulls, finally worked out the bugs: good hp,torqe, and a/f readings. I could not boost over 1.6-1.65 bar (4th gear pulls). BTW, the hi-boost knob on profec-b is turned up all the way. Decided to tighten the allen bolt on the bottom of the wastegate to see if I could achieve 1.8 bar. The bolt was turn 180 deg, dyno'd, and same thing. Another turn this time but 360 deg, dyno but this time about 6krpm, power curves drop (boost dropped 1.4 bar). When the boost dropped, it sounded like something popped off.
I was sure maybe one of the ic pipe fittings but no sign at all.

Leaving the dyno place, I got on it and noticed a loud sheeeshing (sounds like blowing air out of the air compressure) at 4.5-5krpm all the way to redline. The sound is coming from the wastegate area and only hold about 1.3-1.4 bar.

Next next, adjusted the allen bolt on the wastegate back out and took it for test drives, still same thing (loud sheesh noise and only 1.3-1.4). Repeated this 4 or 5 times and same thing.

I know that the profec-b could only support ~1.8 but I'm nowhere near that.

Has my wastegate gone bad? diaphram? spring?

Please help.
Thanks!
 
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