I am baffled at the dyno that shown only a 1hp increase with the GMPP exhaust.

I have a 2 1/4 exhaust on my wife's 03 Sunfire, and the Ecotec definitely got way more than 1hp from it.

Since these newer Ecotecs are the fly by wire and may have other computer program differences, maybe they do not react to the larger exhaust. But I doubt it...

So my question is, should I just get a 4:2:1 header and skip getting the larger exhaust?
If it is only a 1hp gain, I am guessing it is already close to optimal.

I could be wrong, and is why I ask.

Anyone dyno their Cobalt with just adding a GMPP exhaust or really any brand or custom make exhaust?

 

Where is this 1hp increase dyno?

Either way, a header will net you some nice gains.

 

Ever squeezed an end of your garden hose?

Thats what your exhaust would be like if all you got was the header.

Go get a header, a 2.5" dp w/ a high flow, or GUT your stock CAT, 2.5" piping for the cat-back, w/ a magnaflow on the end. And make sure you tune the car... it's wonder why so many spend $1000+ on a full exhaust to see a whopping 5 hp gain.

 

He has a 2.2.

A 2.5" exhaust is probably not needed.

 

Honestly unless you put the car on the dyno the same day, same humidity, same temp, same coolant temp and only changed the exhaust dyno numbers are irrelivant, they are only to extend a person's *****. If you feel a difference, like the tone, see a 1/4 mile difference, you can know it did more than 1hp.

Not meaning to rant but people need to stop worrying about a dyno IMO, it doesnt matter if you can push quad digits if you cant get it down a track it is pointless.

 

If he's stock no it isn't... nor is a full exhaust.

You just don't gain numbers from exhaust.

I dunno what his plans are; but it would not hurt him to run 2.5".

He won't see crazy numbers w/ a full exhaust. but if tuned for it, he will see an over all improved curve.

 

If you're a 2.2, you're not going to get any real gains from a catback. Now, if you were to throw in a better header you would get a little more, but still don't expect more than about ~5 hp. A good tune is one of the better mods you can do. Header with stock exhaust is not going to be any better than stock because while the flow is good out of the header, it's going to hit a brick wall when it hits the 1.5" stock catback.

Either get both catback and header or don't get either. Then get a tune.

If you're trying to do it the cheap way, go get a LSJ header and port it, and then put on your catback. One of the main reasons that you're not getting any real gains is because your stock headers are so bad.

 

+rep to you sentry.

 

http://www.gmhightechperformance.com...lt/page_3.html

The above article shows that the GMPP exhaust gains only 1hp.

 

Get tuned dude. Ive done full bolts on, spray, whatever else. Just not the tune yet. If your car is a 2007 buy Ls2edit from carputing. You buy it once, tune your car forever, every mod you do, mod the tune, Then you will notice everything you do to it. a stock 2.2 doesnt even need an exhaust upgrade IMO

 

Go to your local muffler shop and get some piping bent out for you get a header...any will do really just get name brand and get 2.25 all the way back 2.5 isnt really needed from your header but get a 2.5 downpipe for sure our downpipe well and exhaust looks like it can go on a golf kart and get a muffler of ebay u need full exhaust and intake to feel more power they kinda work off each other and just like
stevenfit said about the garden hose is right wont really gain much...p.s.get a tune after so you get oyur moneys worth

 

not trying to go off of topic or bash the thread but i have a question...
i dunno a thing about tuning and say if i wanted to get and exhaust, header, downpipe..etc where would i take it to get it tuned and how much would it cost?

 

i have been driving with a ca v1 header and an ss/sc cat pipe for at least 10k car felt great. i put on a cat back exhaust, and it got louder. thats about it.

 

If you are an o5-o6 you will be going through Trifecta if you are o7-o9 you should be able to use ls2edit. search them here, there is a world of information on them.

 

okay thanks!

 

No problem bro. I know I am not an expert on either so searching would be your best answer without getting flamed.

 

Think of your exhaust like a chain. It's only as strong as its weakest link. There are several parts in a full exhaust. In order, they are...

Header
Downpipe (with cat)
Resonator
muffler
and all the pipe in between

If you open up one part, like the header, but leave the rest of the system stock, you really haven't improved much of anything. To truely get the benefits of a performance exhaust, you have to upgrade the entire system with matching parts. By matching, I mean matching each other. Such as keeping the same pipe diameter throughout.

 

My GMPP Cat-Back made quite the difference. I think that the site owner dyno'd his for a 12whp gain.

My header and downpipe made a big difference too. They are for sale as well.

 

free CAI tri y header and dp from doing some work on a 2.4 (turbo swap), free 2.5" piping from doing work on another, 70$ for a muffler from the classifieds section, and some welding...and we have a sweet flowing exhaust

 

to OP: no

 

yeah no kidding, my last two threads got locked, but that will be the last thing i say about that....so anyway..