Just finished doing the LIM gaskets, elbows, vac lines, and just some cleaning on the new 07 GP family member and while i had it all apart installed a ported and machined lower intake and blower. Overkill 04-05 PCM as well for use in current and future upgrades. Now anytime i go over about 4500 RPM boost drops by half. I can hear that the blower isn't whining as high pitched as it should. Had it scanned and theres no sudden change in A/F ratio, no knock, no unusual change in timing, no misfire. Idles fine, accelerates fine until 4.5k or higher. Belt slip maybe?Got the ZZP oversized tensioner pulley to take up the belt slack.
Maybe Boost leak past the bypass butterfly?

Other mods include, FWI, ZZP DP, AL 104's, 3" exhaust, borla pro xs mufflers, 3.6 MPS, if any of this helps.

_________________
07 GT|:| Overkill PCM| Full 3" exhaust| Headers| Cat & EGR Delete| PnP Heads, LIM, Gen V blower| 1.9 Rockers w/ 105 Crow Cam springs| 3.4MPS| Homemade Wizaired CAI| AL 104's| 180 T-stat| 0 KR!

Check all your vac lines and check the vac tree on top of the S/C for any cracks. I doubt you're maxing out your're injectors since im not maxing mine out yet and it is possible you're getting belt slip. Does the boost climb nicely then just stop or does it kind of pulsate?

Btw off-topic but how do you like the borla xs's?

_________________

GPDIY - For All Your DIY Needs
VS CAM|3.4|HEADERS|FWI|42.5#|HPT|6000k LOWS|8000k FOGS|

Fixed the problem, the belt had a tear in the middle of it that i couldn't see and was too loose as a result, threw a new belt on after i got back from training and it runs like a champ. I like the pro xs set, it seems to let it breathe very well, no drone like the flowmasters i had, and they really let you hear it when you give it the pedal. Plus it's Borla, can't go wrong

_________________
07 GT|:| Overkill PCM| Full 3" exhaust| Headers| Cat & EGR Delete| PnP Heads, LIM, Gen V blower| 1.9 Rockers w/ 105 Crow Cam springs| 3.4MPS| Homemade Wizaired CAI| AL 104's| 180 T-stat| 0 KR!

Glad you got it fixed. I'm planning on selling the flow masters I've had in a box for a year now and was looking at the pro xs. You wouldn't happen to have a sound clip would you?

_________________

GPDIY - For All Your DIY Needs
VS CAM|3.4|HEADERS|FWI|42.5#|HPT|6000k LOWS|8000k FOGS|

Ill try and get a video posted whenever i get my camera back from Chicago. Accidentally left it at the relatives' house :-\

_________________
07 GT|:| Overkill PCM| Full 3" exhaust| Headers| Cat & EGR Delete| PnP Heads, LIM, Gen V blower| 1.9 Rockers w/ 105 Crow Cam springs| 3.4MPS| Homemade Wizaired CAI| AL 104's| 180 T-stat| 0 KR!

Alright, sounds good.

_________________

GPDIY - For All Your DIY Needs
VS CAM|3.4|HEADERS|FWI|42.5#|HPT|6000k LOWS|8000k FOGS|