I posted this in Tech, but nobody comments on it. I figured I would post it here since there are a lot of STS powered trucks including my old Avalanche that had a GT-35 STS kit on it.

I have a 2005 GTO M6 with a FAST 90, Kooks 1 7/8 catless headers, and a huge 242/248 .62x/.61x cam on a 111. I am curious what it will do with a intercooled STS GT-70 kit. I am also leaving my headers in and wrapping from the midpipes back with header wrap. I don't care if it doesn't spool until 4000rpm. I'll just shoot it with a 50 shot of nitrous. I have read about people running cams with turbos in the 108-112 lobe separtation range, so it can be done. I am mainly concerned with reversion. What do you all think? I've also got 3.91 gears, so I'll be able to keep it in the sweet spot of boost once moving down the road. I'm mainly building this thing to be a freeway missle. I can swap the gears out to 3.46 if I need to though. A buddy has offered to trade for my gears.

 

You have the completly wrong base,but what the hell.Do it anyways.Definitely switch the gears or it will never spool.

 

Since it's already tuned, when I add the turbo it shouldn't be that hard to tune it for 5-7psi should it?

 

The tune will have to change alot.You should install bigger injector's,drop timing and change the fuel table.With that Cam it might be a bitch to get right.

 

Its a WHOLE different kind of tune with FI.

 

you could leave everything else, just swap out the cam, and bigger injectors .. . . . .

 

I have a volunteer that did his own cam swap in a 04 GTO, so I think I may have Ed Curtis make me a cam for me. Probably better to do it right the first time. Although every bone in my body wants the turbo on NOW. lol

 

Use your stock cam. Thats what I have in the 5.7 and it works great.

 

I'm finding that out real quick.