07 Grand Prix Mods

**chadslit** · 07-10-2009

Hey, I'm new to this site and just recently purchased a 2007 supercharged Grand Prix. I would like to get a few extra horsepower out of it and was wondering what size supercharger pulley I can install without adding a intercooler or bigger injectors. I have a friend who can do some programing work for me also. Also what kind of horsepower gains can I expect with a pulley and programing? I dont want to go too crazy, because I still need to get decent fuel mileage (the wife has to drive it, too). Any help would be great. Thanks.

**blowfishRus6** · 07-10-2009

you cant tune your computer, they dont have the software for 06+ BUT i have an 04 computer that you could tune and would work in your car. the fuel gauge will be backwards tho, but atleast you can tune it. send a pm if intrested.

dont touch the pulley tho, not with out a tune and some exhaust mods (headers or downpipe and plog, cat-back wont help you any) and an intake so you can hear the supercharger

get the car breathing good before you add more boost to it.

**GeeBee** · 07-10-2009

Aye read up on the KR thread before you mess with smaller pulleys.

The front manifold is an overly restricted bad casting - building more boost with it will leave you with excessive KR / chipped pistons.

Also the gen 5 blower moves more air and will make you engine more prone to KR than a gen 3 blower. Keep this in mind when people are talking about pulley size / supporting mods cause generally they are talking about an l67 with a gen 3 not an l32 with gen 5.

**blowfishRus6** · 07-10-2009

compared to the gen III blower add one size to compare. 3.4 would = 3.5 for you. the gen V is like said more efficent.

we also have bigger valves in our heads

**blueguy** · 07-10-2009

More like a 3.6"

http://www.grandprixforums.net/f81/s...car-17482.html

**chadslit** · 07-11-2009

Thanks. I'll probably start with the power log and downpipe. It just happens that ZZ performance is about 30 minuites away from me.

**chadslit** · 07-11-2009

Would you guys reccomend the u bend delete pipe and the front power log, or the downpipe and power log for the best bang for the buck?

**blowfishRus6** · 07-11-2009

04+ dont have u bends.

you could find headers for the price of powerlog and downpipe for added breathing.

**07gt** · 07-23-2009

dont wanna steel your thread but i also have a 07 and was wondering what all we can do before we have to tune the comp. would a cai, power log front manifold, be ok? what about rocker arms? thanks

**SlowM90** · 07-23-2009

I have a 07 and my first "mod" was a intake. You can order a KN intake system the 05s will fit. And I got a magnaflow exhaust system. I now have the FWI and OMG! Best cheap mod ever!!!