I have looked on youtube a shitload plus on here for an exhaust setup thats not crazy loud and little to no rasp, but still gives decent performance. This is what i've come to and it seems like it may be a pretty reasonable priced route as well. get the stock catback taken off and weld 2.5" stainless mandrel bent pipes back to this muffler along with welding in the stock resonator. A question I kind of have is will this still gain me decent performance and will the welding and everything workout good? like will the stock resonator work fine? i've taken all my cars to this guy along with all my friends, he does a very good job and is no nooby at welding so i'm not worried about any leaks or anything.

Megan Racing MOE SS Universal Exhaust Muffler: 2.50" - eBay (item 220692314008 end time Jan-03-11 09:03:17 PST)

and in hopes of it sounding like this?

YouTube - 07 cobalt ss s/c

 

vroom!

 

Cat back is exactly that. Replacing from the cat back. A little gain in the top end but overall no performance gain. If you want an upgrade you need the header/dp to make it worth while. People that buy cat backs just want the sound.

 

eventually i'll add to it with a header downpipe combo most likely from zzp, but for now i just wanna get the catback part taken care of. mainly i'm just wondering what all i should have replaced? i've heard the stock exhaust is 2.5" til you get to around the axle. and didn't know if the stock resonator would work good with this type of setup.

 

the stock resonator is fine, the restricitve area's of the lsj exhaust is 1. The header 2. The crush bent non highflow cat downpipe 3. The lunchbox rear muffler doesnt flow for **** 4. The 2.25" downsize before the axle

 

thanks! so should i just have him put a mandrel bent peice from like the resonator to the new muffler? I wanna try and have as little new piping as possible i guess, but still make sure everything is 2.5"

 

ya thats fine, but like stated above, your not going to see much gain, more of a mod for down the road if you go turbo or get a TVS and start pushing over 275whp

 

yea i won't be doing that. at least not in my plans. eventually like i said i'll get a new header and downpipe most likely from zzp, but for now just the catback. i can still expect to see some gains correct? minimul of course.

 

bump

 

The cat in the stock lsj downpipe is high flow.

The stock lsj downpipe is mandrel bent. Maybe you mean where the rear 02 sensor is mounted is crushed.

The restriction in the stock downpipe would be the 2 1/4" inlet at the flange, the rear 02 dimple, and the neck down right before the rear flange.

The inlet of the stock resonator is only 2 1/16" (restriction).

It's true though that the stock downpipe is the most restrictive portion of the stock exhaust.

 

You will see gains from a catback. Nothing huge, but def a little more pep.

 

so should i look into getting a different resonator thats 2.5" down the road too?

 

It sounds like you want to piece an exhaust together by the way you are asking questions in this thread.

Your best bet would be to do it right the first time, and purchase a quality header downpipe setup and catback exhaust. An LSJ can sound good, but with cheap exhaust parts it will sound crappy. What are your future goals of your car? The LSJ responds nicely to exhaust mods, and will help expand futher performance potential if you decide to make more power.

 

nothing more other than an intake.