just watch out. some peopel have reported on the cobalt forums that the ebay headers came with bent flanges. check them before installing. expect about 5-6 hp.

 

thanks for the info, how can I tell if this header is bent

 

Take a straight edge and lay it accross the flange to make sure it is flat.

 

Ok, great idea.

Thanks

 

any flat surface will work also. if it rocks its warped. if so send it back and ask for another one.

 

The 3 studs that came with the header are the wrong size, need to drop everything and drive over to the muffler shop to get the correct studs for this header.
Also need to get a plug to block the hole used normally for the senser on cobalts, the rest of this header seems to be ok.

Information for other members that want to install the same header

 

That header would be a cobalt-addiction.com header. works very well. comonnly call a CA V2 header. And you need an O2 bung plug. Should be easy to find.

 

Yes, I checked out your link, yes it's the same, thanks for the info, it's finally installed.

I will post an update in a week, this way I will have a better idea on gas millege and performance.

 

Once the original exhaust manifold was removed and compared against the new one, WOW !, what a difference.

The new manifold has a major improuvement on the exhaust flow, I have not yet seen a change on HP, but the gas millege is better.

This is my first mod which I recommend to every one, the sound has not changed.

The next mod 18" mags from the HHR SS, probably will lower the vehicle as an SS.

 

What mileage gains have you been able to verify? I pt a complete 2.4 exhaust system with single larger cat and a Cherry Bomb Vortex muffler. It really breathes and sounds better but the mileage improvement was minimal.
I certainly would put a header on there if it was to give any decent verifiable gains in mileage.