Closed-Loop EBC Issues
 

I have recently been trying to dial in my closed loop EBC with setup mode and am experiencing a baffling problem. Closed loop EBC seems to do absolutely nothing until around 3800RPM. This would make sense with a big turbo but I am running a Precision 4828 which is roughly equivalent to a GT2860RS on a built 1.9L block. Furthermore, I have logs of the turbo spooling MUCH faster (see 2022-05-13_17_modified.msl) previously. It almost feels as though the wastegate is wide open until 3600-3800RPM.

Setup:
Precision 4828, old BEGi cast mani, ARTech 3" divorced flow downpipe, fill 3" exhaust
MSLabs MS3 Basic
Genuine MAC EBC solenoid

What I have tried:

1. Put in a brand new MAC solenoid because the old one had some fraying wires. No change.
2. Various changes to duty cycle in setup mode -- changes are clearly apparent above that 3800RPM mark but appear to do nothing below it.
3. Confirmed continuity between ECU boost pin and 12v power for the solenoid.
4. Shaft play seems minimal on the turbo and intake setup is FM's.

Current theories:

1. Turbo is going out :(
2. Wastegate needs to be adjusted for some inexplicable reason?
3. Some inconspicuous wiring issue is causing the MAC solenoid to work intermittently.
4. I am missing some setting here or there that is preventing EBC from kicking on.

Has anyone experienced anything like this or have any suggestions as to where I should begin looking? Or is this reasonable spool time?

It didn't take long, but I may have just found the culprit:
https://cimg3.ibsrv.net/gimg/www.mia...8227aca2fe.png
Missing a nut/locker on the downpipe, lower right nut was originally loose, gasket has a hefty leak on top.

Next question is, how do I prevent this? Should I run a copper gasket or no gasket? Are there any locking nuts or loctite-type chemicals I can use to prevent this?