Ok I might sound a little stupid but I just want to know when would I need to use a downpipe? and also How big and what does it do??.... I want to get a corsa touring exhaust, DC headers (not sure on the brand yet), would I need a downpipe then?or can I just use the GMPP manifold without the Downpipe. Im not sure what way to go....

 

do you mean when do u need to get a new or better downpipe?

 

You dont 'need' a downpipe because your car already has one lol. a downpipe is the piece of the exhaust system that links the header (aka exhaust manifold) and the 'cat back' exhaust. The stock downpipe also contains the catalytic converter. If you replace the downpipe you can either remove the cat completely or go with a high flowing cat to replace the stock one. Either way, in California at least, when you need to have your car smogged it will not pass if you alter your stock cat either in location or removing it all together. So basicly you only need to replace your downpipe if you're looking for horsepower gains.

I'm not sure what you mean when you say 'DC headers (not sure on the brand yet)", simply because DC is the brand that makes the DC header. Not to mention the cobalt only has one 'header' so technically you'd only be replacing the one. As far as the size on the downpipe, that would depend on what sort of mods you have and also on what size your 'cat back' exhaust is. I'd recommend something around a 2.5" downpipe. 3.0" is most likely too large for your application.

If you have any other questions or I can help clarify something just let me know.

-Beck

 

exactly, Im not sure when to, either after modifying the exhaust or the headers or what.

 

the DP will just make your exhuast setup more freeflowing, to get max gains from an exhaust setup its best to fo the header, downpipe, and a cat back

 

Honestly the stock downpipe in the cobalt is the most restrictive part of the entire exhaust system (the three main components in the cobalts exhaust system are 1.) The Header (exhaust manfiold) 2.) Downpipe 3.) Catback Exhaust)

If you decide to go with an aftermarket header and catback exhaust it would be wise to purchase a downpipe aswell.

The header is the most difficult piece of the exhaust to install, however a downpipe can easily be added later, you do not need one if you purchase a header. But as i said before, its the most restrictive part of the exhaust so it would be wise to replace it if you're seeking performance gains.

What exactly are you looking for out of this car? Do you want performance, or just a nice exhaust tone?

 

I am looking for performance. I know I have heard that changing the downpipe does alter the cars tone. I do want performance but I don't want it to be super load.. being in california you get bullcrap tickets for everything.... So thats why I was asking about changing the downpipe. I had a friend who kept bugging me to change the downpipe to 3" to 3.5" and I didn't think that was wise for the balts and he knows nothing about our cars.

Is it better to go with the GM manifold and GMPP exhaust or corsa exhaust?

 

honestly i wouldnt go over 2.75" and i'd even probably stay at 2.5". 3.0"+ is just too large unless you're putting down about 300whp (which you wont be even close to with an intake and full exhaust)

I'd go with 2.5" header/2.5" downpipe/2.5" catback exhaust

Being that you're in cali i'd recommend getting a high flow cat on that downpipe aswell because i've been pulled over by ******** cops before and had to pop the hood. If you at least have a cat they probably wont bother you.

Gm Exhaust manifold isnt really a true header, it will probably show you the least performance gains out of all the 'aftermarket' headers, however going with gmpp header will not jeapordize your warranty (if you're even worried about it).

I'd go with ZZP Header/Downpipe and then what ever exhaust you like the sound of (because that mainly determines the loudness and tone of the exhaust, however the downpipe and header will change it slightly and make it a little louder).

https://www.zzperformance.com/cobalt...cts.php?id=155

^^^^^
check out that link.

As far as the exhaust tones, there is an exhaust thread around here somewhere that has video/sound clips of the different exhausts. The GMPP Sport exhaust sounds pretty nice imo. i also think the magnaflow is nice.

***EDIT***
Found the link to the exhaust thread, check it out:

https://www.cobaltss.net/forums/show...exhaust+thread

 

Thanks for all the help Beck.. Its seems you pretty much all my questions... and no I'm not worried about the warranty its all ready up and I have about 40k on the car. I think I'm going to run the Mid length header and downpipe combo from zzp with the magnaflow cat option with the corsa touring exhaust.. Hopefully its a good combo..

 

06's do have a powertrain warranty of 6y/60k miles . Just a heads up .

 

honestly if i were u i wouldnt go with the dc header on the 2.0 supercharged as it is designed more so for the 2.2 and 2.4