you might have a fitment problem bolting an aftermarket downpipe to the stock header , mine rubbed like a mother ****** , actually now that i think about it , it was the ZZP header with the stock dp and exhaust

 

I haven't read any problems about bolting a ZZP downpipe to the stock header but will let you know when i install it.

 

CAT BACK! The muffler is the biggest single restriction we have!

 

Can i just swap out the muffler?

 

na its cause i had the ZZP header bolted to the stock dp , exhaust , thats when it rubbed , my mistake

 

Yeah, you can... but have them replace the last like 2 feet of piping when it goes over the axle it goes to 2.25" piping have them replace that section with 2.5" and you will have a full 2.5" system! Which is what I did, just I replaced the resonator with a high flow unit!

Magnaflow oval muffler with stock tip for (STREET CAMO!)

 

yes i already told you that. if you put in axel back exhaust you might as well have 2.5 inch exhaust , like i said originally i would buy a muffler online for 75 dollars and take it to an exhaust shop and have them weld it for another 25 you will gain about 1-2 MPH in your trap speed its been proven before by someone on this site

yah thats what i had except i had 3 inch piping all the way from the header back, and i had an aftermarket tip with a magnaflow straight through muffler sounded awesome , and 1 resinator

 

I mean to get the most performance, you should do the whole thing... I found the limits of the stock system (right around 240-250 hp) And you start blowing **** out of the tailpipe!

Werd, for Street Camo

 

Right.

The other benefit of wrapping headers is to keep under hood temps low. It's more of an old skool trick because of 14" air cleaners sitting on top of a Holley carb. With a CAI in place that's not so much of a concern.

But 99% of header companies will void the warranty if you use wrap. The heat is so extreme it will deteriorate the headers very fast.

An alternative to wrap, which I'm sure you all know and heard of is ceramic coating. If coated both inside and out, the under hood temps stay low and the heat stays in the exhaust stream.

I'm not sure about headers for the Cobalt, but I know when I owned a 3rd gen Camaro there were a few companies that sold ceramic coated headers along with a ceramic coated Y-pipe. Even so, any exhaust piece can be sent off to a company like Jet Hot to be coated.

I'm sure things like mandrel bent pipes and ceramic coated parts help all the way through the exhaust system, but not as much as getting rid of the restrictive muffler. A good muffler on a stock system would be a cheaper way to gain a good amount of flow than putting the best exhaust system in front of a restrictive muffler.

Oh... and for those looking to run a 3" exhaust, a tune will be needed (and probably larger injectors. The A/F ratio will change and without the proper ratio power may be lost.

 

Onyxd04Redline - let us know how it sounds. im also torn between cat vs catless on stock catback. i tried removing the converter on both of my previous cars (j-bodys) with full exhausts and both sounded like a penny in a tin can.

 

You can't expect much from a 4cyl. I can deal with the crappy sound aslong as it's a good increase at the wheels.

 

Atleast you are reasonable! LOL! People ask me all the time "I want a free flowing exhaust, but I don't want it to sound like a 4-cyl". What else is it going to sound like?! LOL

 

Guys how many times have we gone through this... a 3 in is too large to run on our cars.... unless you run turbo,.... as stated above...

 

You guys really need to read this thread.

https://www.cobaltss.net/forums//showthread.php?t=67539

And replacing anything before the stock muffler is going to yeild you 0.0% gains. Its not getting the exhaust away from the engine any faster when it is still going through the restrictive muffler. Unless you have an exhaust leak!

I disagree.

http://s135.photobucket.com/albums/q...t=MOV01249.flv

 

that thread is interesting.
but by no means accurate IMO.
the sources for the information are not necessarily directly applicable to our vehicle

I will continue to believe the personal testimony of multiple people i have talked to with 3 inch customs, some quite highly modded, who have said there was a definate loss of power low-mid.

IMHO 3 inch is to big for this car with the stock blower.
and after all this time not 1 person will post a dyno of it, which leads me to believe its correct.

 

A lack of evidence FOR something is not support for evidence AGAINST it. But also agree. 3" is retarded on stock blower, regardless of how cool your shiny new pulley is. Your restrictions are manifold, cat, and muffler. And I wouldn't even call the manifold a restriction until 2.7" or smaller pulley.

Sure I don't have any dyno evidence to support me but I do have the hands-on experience of about 50 Cobalt SS's.

 

I know its not evidence. but it helps to support it to me. I believe it based on first hand account evidence, no dynos is just another little hint that makes me believe that its true.
because no one wants to post a dyno where they lost overall power.

 

Thank you. The flow calculation are estimates but at least it is something. Most people don't even know what the most restrictive part of the exhaust is. DP? Muffler? 2.25" bend? That thread will give them a starting point. EVERYONE SHOULD READ IT!! It should be a sticky.

+999999 Of course people are going to say they love their 3" exhaust after they spent all that money on it. Then 3 months later they put it up for sale!

I don't have any dyno proof but even switching from the stock exhaust to the Magnaflow 2.5" I have noticed a change in my power curve. With the stock exhaust I had more tq between 1500 and 2500 rpms. Now the power comes a little higher in the rpm range.

 

That can't be based on the SOTP meter.

You may not have lost anything at all between 1,500 and 2,500 RPM, but gained more up higher so now the lower RPM feels weaker. It's all perspective. Know what I mean?

 

yeah i know 4 bangers sound like p00p. i just dont want that tin can rattle sound that came after i removed the cat. regardless of what catback i was using it sounded like ass. i think 4cyl cars should be seen, not heard before you can see them
give us an update on how you like it whenever you get it.

i hate 4 bangers. cant wait until i can afford some real displacement

 

That could be true to. Maybe the power after 2500 is that much more then is used to be.

IDK if you watched my video but my car roars! I have a GMPP Manifold and 2.5" Magnaflow cat-back. I have a ZZP dp coming soon. I wish I could have dyno'd the car before and after. Going off the info in that thread this will be my setup:

GMPP Manifold 455 CFM
ZZP 2.5" catt'd dp 450 CFM
Magnaflow 2.5" cat-back 450-500 CFM

450 CFM should work well on a Stage 2 LSJ.

Oh and don't get a catless dp if you care about your cat-back. The extra gas that would have normally gotten burned up in your cat is now making its way to the resonator and muffler. When the gas burns up in there it will ruin the performance and sound of your exhaust.

I know a lot of people do it on here and then wonder why their exhaust sounds like crap after 6 months.......

 

Yeah, it definitely coats it in soot, but it is especially worse for people who do not turn off their COT controls when they take the cat off. Simply taking the code off doesn't cut it but people think that's all they need.

Otherwise you will have like a 9:1 AFR LOL!

 

i don't know of any 4 banger that doesn't sound like ass with aftermarket exhaust.

 

Ass... I hear AIRPLANE THOUGH!