Vortech with 3.12 pulley

[KY_BOB]

I have a '02 5.3 Avalanche with a Vortech blower. It originally came with a 3.33" pulley on it and was listed by Vortech as a 7# supercharger kit. With that set up I was seeing 6.5-7# of boost at my 5800 shift point.

I changed to a 3.25" pulley, which I know isn't much of a drop but I wanted to take it one step at a time. With the 3.25" pulley I would see a solid 7 to 7.5psi of boost at peak rpm.

I then went to a 3.12" pulley and am now seeing about 9.5 psi at 5800 in first gear and only about 9 psi at 5800 just prior to the 2-3 shift. I don't know why I see more in 1st gear than 2nd

Most everyone that I see with this pulley on a 5.3 is seeing about 11-11.5# of boost. I have a stock cam and shorty headers so I know that I'm not just running less restriction that others. I called Vortech yesterday and their tech said that that sounded about right but I wonder.

What do you guys think? Do I have a problem or not?

Could my gauge be off or slow reacting? I do have the line that runs to the gauge T'd to run the line to my meth injection. Am I loosing boost somewhere? I've looked everywhere that I could think of. I don't think I'm having any belt slip because I can hear the belt chirp when it shifts or if I get off of the throttle quickly just before the blow off valve dumps the pressure.

I know that Flabouy is seeing over 11 psi with this supercharger and pulley and he has long tubes, no cats, and a aftermarket cam. Why am I not seeing as much?

Any thoughts are appreciated.

[SCIV]

I don't think it is a problem, but then again what do I know. I added a Procharger with 8 psi an only saw about 50 more hp out of it. Come to find out it is my cam.

I think the pressure drop is because the head unit is becoming more heat soaked through a WOT run through 1st and then through 2nd. More built up heat = less ability to compress = less boost.

I could be talking out my ass though, but at least it sounds halfway intelligent!!