07BOSSGT_S197

I'm having a set of 3.90 gearsinstalled next week and the perplexing question is running through my mind....SuperCharge or NOT to SuperCharge?????! Blower or Centrifugal???? What bothers me is that there are so few applications for an 07 GT out here, and the ones that are available are kind of pricy. I'm still running the stock drive shaft (I'll probably want to change that out!). Also, is it worth it to go with WaterMeth injection? Cooler temps = better boost and lower gas consumption right? I have a tuner already, so how do I get a new tune downloaded saying I DO go supercharged? Can it just be downloaded from SCT (have the SCT SF flash tuner)? Am I just wasting fuel with 3.90s and just trade down to 3.73s? If I could find the rpm to final drive ration equation that might be helpful. [:-]

s197richie

from what I've read 3.90s should be fine for FI...um, remember these engines have cast rotating assemblies and have been known to have issues above 420hp plus the trans is rated for somewhere between 360-390ft/lbs...IDK if you want to prep your drivetrain for the FI, or upgrade it as stuff breaks, problem with the latter of course being if you put a rod through the block...as far as a s/c tune if you have an sct I'd go with brenspeed...IDK anything about watermeth...and as far as picking out a s/c goes, seems like the twin screw setup makes a good amount of power for the $$$...hope this helps...

blackhorse05

the 3.90 wil be fine. i have the saleen blower. i make 452. my tune is custom but you can get tunes emailed to you. then with a cord upload it to the sct. i still have factory driveshaft. it isnt needed to upgrade, but a good mod. ill be getting one soon

Heavyg72

Agree on the 3.90's...you should be fine with F/I. I have the Paxton supercharger and hit 482rwhp but tuned it back to about 450. I haven't upgraded the drive train yet but did just order the TCI torque converter and should have it installed in a few weeks. As far as tune you can go with a custom dyno tune which the shop will put on the tuner for you or you could order one from someone like Brenspeed. If you go with the supercharger then I really recommend a custom dyno tune to make sure your AF is good and that everything is the way it should be. Good luck!

hawgman

I have 4.10s and 500 to the wheels. The 3.90s will be fine for the application you are questioning. BUT... FRPP doesn't make 3.90s for the 8.8" rear end, and every other brand that I know of ( especially Motive ) are noisey as hell.

zkiller

I would supercharge first and then decide on your gears.

mygt500

1+

07BOSSGT_S197

I did as sugested and had a tune emailed to me via Brenspeed. After giving them all the aftermarket mods I had put on and where/who did the initial tune for me (STEEDA). They pretty much just fine tuned it. Oh...and the whine from the gears....not so bad and they are Motive brand. Not sure if the Royal Purple has anything to do with it or if it's just because they're so new. We'll see though. As for the FI. I'm going to go with ProCharger Stage II. They seems to have a pretty good proven set up. One thing I'm kind of perturbed about is Mustangs Unlimited (which is close to where I live) sent me the wrong wheel and I have Nitto 555 and three, yes just THREE wheels sitting in my dining room!! A definite eye sore. And come to find out that the fourth wheel is on BACKORDER!! Ok I'm done now....