So my setup is a Log manifold with a 60trim t3/4. I have the s300 with the boost solenoid for boost by gear. I am tuned to a max of 22psi. I took my car out the other day and now it is breaking up on the top of 3rd and 4th gear. I am hitting boost cut as soon as the car sees high boost. I took the boost cut up to see where its at and I hit 30psi and will hold it too. My question is...Why have I had no problems all year and now for some odd reason it wont hold what I am tuned at or what I tell the S300 to have my boost at? I swapped the bov and gasket to a real Type-s and still same problem. Any help is highly appreciated.

 

what boost control solenoid are you using? with my mac one, there must have been some break in period. i had the duty cycle set at 72%, and that worked fine for almost a week, but then i started hitting the boost cut. dropped it back to 63%, and now it's holding steady.

 

Check your vacuum lines that run to your boost solenoid/wastegate etc.
If that fails, take the vehicle to your tuner for inspection.

 

All vacuum lines are good. Do you think the diaphragm in the gate could be bad? It looks a little worn.

 

Sounds like possibly a leaking solenoid.