Well after taking apart my car yesterday to install the new GM Extrude Honed Manifold I noticed that the 2007+ LS model cobalts come with the less restrictive SS/SC manifold stock adn not that super restrictive manifold with the D shaped flange side outlet the 05 and 06's have. So instead of gaining a whole lot of flow I am only gonna gain teh 7% GM quotes for the SS/SC guys who upgrade to the extrude honed manifold. *BONK*

 

that sucks, have the manifold extra honed then by a machine shop

 

Meh Im just gonna stick with it for now. And I think Im gonna start making double payments and soon as this bitch is payed off Ill start my 400hp build.

 

At least it's nice to know Chevy is providing better performing parts for the base models! Should have been that way from the start....

 

i wonder if that's where the extra 3 hp came from? but 7% is still not that bad, it's about 10 hp which is to be expected...

 

Not to rain on anyone's parade, but I really don't think you're going to get 10hp out of a honed out exhaust manifold.

Maybe 4-5hp, and that's stretching it. A full header like CA's only claims 8-10hp on a 2.4.

 

I think the 3 HP IS because of the "SS" manifold. Chevy knocked down the HP with the '07 cam (less agressive profiles -- per the GM cam spec sheet available at CED) but probably gained more HP via this manifold.

 

One thing that gets me is bone stock my friends 06 LS Dyno's at 126whp 137lb/ft
On the same day I Dynoed my stock 07 LS at 149whp 141lb/ft. Chevy claims 3hp difference stock but we did our cars at the same shop 1 hour apart when they run this 3 pulls for $60 at teh end of the month. Now I have GMPP Intake, GMPP Manifold, and Magnaflow cat back exhaust. I honestly think Im at or above 160whp now in my LS.

 

Factory Freak? Chevy built these cars so fast, I wouldn't be suprised if there are quite a few that don't exactly meet the specs.

I ran my car vs my neighbors and I ran her down by like 2 cars.
My 06 LT Stock Auto vs her 06 LT Stock Auto. Stock tires and everything. I didn't run the stall converter at all and she doesn't even know what a stall converter is.

I don't get how to explain it. My car feels much peppier than the one I drove at the dealer too. *I ordered mine new.

 

recap for me: the 07 2.2 has a differnt/better manifold?

 

Yep!!! heres the 05/06 exhaust side manifold.


And the 07 Manifold is the same as the SS/SC's come with.