Hey guys,

i've been playing with my profecB specII for a while now and cant find a happy medium when it come's to tuning it, i want to run 14.5-15psi constantly but all i can get is a constant 13psi that drops off in higher RPM and have the turbo spike to mid 15's....

these are my settings; ( In psi )

Boost: 63
Gain: 20%
Set Gain: 11.5
Warning: 15.8
WarningL: 20%

what settings do you guys use with your boost controller?, i like the quick response the gain gives, but something more stable would be nice, this is on a BNR3 turbo aswell....

 

I will refer you to my thread that was posted not long ago. It really helped me, there is tons of great info. https://www.rx7club.com/showthread.p...=greddy+profec

 

i still cant figure it out, i tuned the boost controller well enough in the first 3 gears however, in 4th and 5th the turbo spikes a fair bit, it spikes the same it did before but holds less boost....

i turned the set gain to 130 and the gain to 15%, i'm left here scratching my head, can anyone help?...

 

It's a lot easier to get stable boost control when your target boost is only a couple psi higher than your spring pressure (but you don't want them to be too close either). On my externally wastegated T04R I run a 13psi spring and I don't have much trouble getting around 15psi steady by using the Power FC built in EBC control. Think about factory boost control systems. The S5's have a 6psi spring and the boost control solenoid bleeds pressure to the actuator (just like a WRX factory EBC) to raise boost to around 8 pounds. The FD's have a wastegate spring of 7psi and the factory solenoid vents pressure from the actuator to raise boost to 10 pounds.

What you need to do is stiffen your wastegate actuator spring pressure to about 12-13psi and then retune the controller. I think the BNR's come with a 7psi adjustable wastegate actuator similar to what you can get from ATP turbo etc. Stiffen it by I believe lengthening the wastegate arm. Disable the boost controller and keep adjusting spring pressure until it will boost around 12-13psi with the boost controller completely off. You can also test the spring pressure with the engine off by pressurizing the wastegate actuator with a regulated source of compressed air. But that would ideally be done with the turbo off the car, which is a big pain in the ***. Retune the boost controller from scratch (go back to the default settings listed in the Spec II instructions) after the arm has been stiffened. Also, if you have anything that can make logs of your boost curve (such as a standalone or Rtek) use that to make logs after each pull.