WTF Shifting vs Boost issue

I’m not one to normally ask questions, but this has me stumped. My 86T will build full 10psi of boost in 1st, 2nd, 3rd, 4th, and 5th if I get on it hard after its been in that gear for a few seconds. If I dumped the clutch from [insert RPM here] it’ll build 10psi instantly. Comes 6,000rpm (full 10psi of boost), quick shift to 2nd, WOT…no clutch slippage, but it’ll only build 4psi then slowly creeps up and finally reaches peak 10psi at ~5800rpm. Quick Shift to 3rd and it’ll build ~4psi and max of 6psi by ~5800rpm…and so on for 4th and 5th. If I get it rolling gently, then cruise in second for a bit then go WOT it’ll jump to 10psi and pull hard right away. If I shift into 3rd like a grandma and cruise a bit then go WOT…it’ll build 10psi and pull hard…RIGHT AWAY. Same for 4th and 5th.

Again, 100% positive the clutch isn’t slipping. RPMs arent picking up while speed isnt, and RPM matches speed exactly as it should. And if I dump the clutch when shifting quickly into 2nd it’ll spin the tires…just not build boost.

Fixed it, was something stupid. Breather hole on MBC was plugged…

i was going to say, sounded like a vacuum/mbc problem

Yupp, I knew it was something stupid. Friends kept saying “are you sure the clutch isnt slipping?? sounds like a boost leak”…but it was actually the lack of the bleeder hole in the MBC holding pressure on the wastegate actuator, making it stay open.