I am experiencing an overboost problem, but only on my primary turbo. For example, the second that I mash the gas (especially in 3rd and up) the boost rises right up to 13-14psi very quickly, I then have a normal transition into the secondary, and when I am on both turbos I get 11psi rock solid like I should. I have my PFC set at .70bar for both turbos, I even turned the solenoid duty all the way down to 20% on the primary with no effect at all on the boost. The only mods on the car are the PFC, Blitz cat back, and Apex intake.. I had this problem even when I had the stock intake box and only the catback/PFC. What could be causing this? I did a test two weeks ago and removed the stock pill, my boost went to a normal 8-6-8 roughly so I put the pill back in.. now I get 14-8-11. What gives? Is it the pill? I have played with the duty cycle and boost settings to no avail.. the fact that it holds 11psi on the second turbo all the way to redline makes me think it is definitely not a wastegate restriction problem. Something is not opening the wastegate fast enough on just the primary..

Matt
93 SSM

 

Matt, try dialing in a little more prespool. This will take some of that boost away from the primary turbo, and help the transition drop.