I just installed the hks evc IV and have my boost set at 1.3, and1.35 bar. Which is 18.5, and 19.65 psi i think. Well my boost spikes up to like 22 or 23 psi and then holds about 21psi to redline. My question is if its really pushing that many psi to redline then how come my car feels weaker than when i was running stock? Could it be my af ratio, or could it be the 91 octane im on? Im in south dakota, so the elevation is higher.
oh yeah and my boost controller is tapped into the fuel pressure vacuum line...should i change it to get a better boost reading?

 

Hells no!!! Never tap into the fuel pressure regulator vacuum side. that signal is inaccurate. Trace the line and you will realize that it splits into a vaccum switching valve. Use the BOV vaccum line.

 

Oh, yah the answer is all the above. The Ecu is pulling timing because it senses knock when you hit 23 psi on 91 octane. Get a SAFC II and tune it. Everything will be ok then.