Boost creep

[JoeB]

I'm having a problem with boost creep and I'm looking for opinions. The really cool thing about the roots type superchargers is the lack of lag. When you stomp it, you got it! If I have a 7psi puley, I should hit 7psi fairly early and it should hold at 7psi. My problem is, I hit 7psi then at high RPMs, the boost will creep up to 9.5-10lbs.

Although more boost may sound good, it is only good if the air is flowing. Simply more pressure in the chamber is actually bad. So far, the best explanation I've heard is that the exhaust gasses are not being scavenged quick enough. The 2 components to that are the exhaust system (headers/y-pipe/cat/catback) and the exhaust valves. Since I have the full JPP setup, I'm convinced that isn't the issue unless my cat is getting clogged. I'm more conviced it would be the exhaust valves. I'm hoping I can get your opinions. TIA -JoeB

[EricSol]

My 7 gives me about 7.5 psi at redline, hmmm. Before exhaust and heads my 5.5 would spike to around 7 at redline.

[esculatus]

funnie, I just changed the pulley yesterday and my PSI reading is always 1psi or .5 psi less ... I think it must be the gauge because when I turn my car off, the needle is about a little bit to the left of 0.