ok before i start, yes i used the search tool and came up with nothing.

are there real gains with this part? I am thinking about it with a new downpipe and hi-flo cat. I want to use this because of warranty concerns, or am i just wasting my time and should do a shorty header or something along those lines?

A local exhaust shop said they'd fab up a nice 2.5" cat-back for me, im going that route, but need info on the extruded manifold.
thanks in advance

 

I would say go with an aftermarket.

 

I have it... IDK if I got a gain or not....

 

i personally would go aftermarket.

 

minumal gains . You will feel a difference once you put the high flow down pipe and the hone mani on . You lose down low but gain in the upper RPMS and high speeds.

 

I've got one, GM states that it flows 30% better than stock.. But if your going to go with a shorty, i'd go for it!

 

Get an aftermarket header. Less cost and more flow=win, win.

 

yes.

 

i had the gmpp header on my ss/na and regreted getting it the day i put it on. heavy and very little if any gains.

 

Remember, this is a ported stock manifold and not a header....the differences are huge.

With that being said, I installed it and went and dyno'd it. I saw gains with it. If you have issues with the 'warranty' then this is the way to go but you will see better gains from a header.

 

great! thanks for the info guys i think i may just go shorty

so the honed manifold is just a stocker thats been cleaned up? its still cast iron im suspecting so there is a weight issue there, especially compared to a header. oh yeah, whats gonna happen if i go catless dp? farts, pops, maybe flames?????

 

WRONG!!! It flows 30cfm more than the stock manifold! I have one on my car, made a tiny bit of difference, if i were to do it again I would have went with a header or spent the money on a 50 wet shot

 

someone got 4WHP and 6WTQ on a dyno with this manifold
I installed mine this weekend and I can feel the difference.

 

for the same price or less, you could have gained 15hp and 15lb ft, and lost some weight. The honed manifold is not worth the money, just like most have said. Its not going to void your warranty either, unless they can prove that the header damaged whatever went bad, wich they would have a hell of a time doing, because its unlikly to do that.....

 

I just ported the **** out of my stock one...free mod FTMFW

 

i would reconed a mid length header and downpipe combo. a mid length will give you good torque gains as well as horsepower gains up high. i found that going from a shorty to a mid length it made the car much more driveable in the lower rpm range, and as an added bonus about 1mpg better fuel milage.

as for cat vs no cat, up to you. there is no real gain between a good high flow metal core cat vs no cat. without a cat you will get a p0420 code (catalist inefficent) unless you delete the code with hp tuners, however modifying your tune will void the warrenty.

just for the record i have a clear image header. their stuff is top notch, id recomend it to anybody. as another note, the dealer cannot void your warrenty because of a header.

 

That was my impression after installing the clear image header. There is significantly more mid range torque, and the car is more drivable. I found that I had to downshift less at highway speeds. Even in fifth gear there is more noticable thrust....

I also have the Clear Image setup with a high flow cat.