rb25 overboostin?

[HPF Chrisk]

Hey guys i have a s1 rb25 swap in to my s13 and here are the following mods, cx racing intercooler, syko dump pipe, megan 3 inch down pipe, 5zigen 3 inch cat back, lightened flywheel and 6 puck clutch.

Before i put my fmic on i had all the same mods and was running boost of the wastegate accuator and was running 5.5psi. The car ran good and did 217whp

Now with the fmic on the car is running 7-9 psi. It will hold 7 psi for a while then on the top end it will go to 9 psi and stick. I dont have a problem with this i just want to know why it is doing this cause nothing has changed but the fmic. WIth the extra boost and fmic i dynoed it and it did 262whp is this about the norm for cars with the same mods? What is causing the overboositing? i have checked for boost leaks and there appears to be none at this time

[the_garynator]

The wastegate actuators on the RB25 turbos are 7psi, so you should be running at least 7psi all the time. This will probably be higher due to your mods, when I had one on my rb20, it ran between 7 and 8. Not sure why you're getting boost creep, nor why you are not getting the full 7psi.

[silviasgp06]

the small stock waste gate opening on the turbo causes this flux. Its pretty common on SAU.

[the_garynator]

weird, mine never did that, although it was an s2 and on an rb20, maybe the higher flow requirements of the 25 are the cause.

[bmadd2402]

this seems to be a fairly common problem with the standard FMIC, Exhaust, intake mods on the 25. Your engine is breathing better, and the small stock wastegate can't keep up with the exhaust flow. if it is consistent, I'd say just go with it. some guys on SAU open up their wastegates by boring the housing a bit to let a little more exhaust out. Could also be your actuator. I'd check it to be sure. With mine, it had some boost creep when i tried to run stock boost, but it liked 12-13psi, and held fairly steady. GL!