I got a 2005 Cobalt SS/SC and was wondering how big the factory exhaust is 2.25" or 2.5" and does it go into 2.25" at the muffler? I have a magnaflow muffler and was wondering if I would get much power increase changing the factory resonator? I just don't want too spend 500-800 dollars on a cat-back exhaust.....Thanx

 

Stock is a 2,5" catback, but the rear section (rear axle to muffler) is 2,25" crushed bend. Replace it to 2,5" along with a straight through Magnaflow. 10 WHP gain.

https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/how-custom-magnaflow-vibrant-2-5-ss-catback-intake-mod-parts-needed-5478/

A catback (or a custom one) is a MUST before making any other mods on the SS.

 

my personal opinion is you won't see any gains from changing the factory resonator... it doesn't even have inward facing baffles... your biggest choke points are the muffler and the manifold

 

i don't think everyone has crushed bends.. when i cut off my stock setup, it was mandrel

 

Thanx alot for you help guys....I already have a Magnaflow Universal muffler on my car with a 2.5" inlet/4" outlet. I was really inpressed with the gains just with changeing my muffler as the stocker is heavy and decreases hp the most. I just wanted too see if it was worth it to change the factory resonator....I just don't see spending 500-800 dollars on a catback the same diameter as the stock system...Its money I can use for the GM Stage 2!

 

same thing I plan to do

 

Its a great mod man...I spent 200CAN on the stainless magnaflow race series muffler and 50bucks too install it! Awesome cheap mod too make good hp gains....

 

I wonder if you can order replacement parts for any of the cat-back kits yet?

If you can a guy could just order the section of pipe that goes over the axle to the muffler. It would be stainless and have all of the correct bends and hangers.

I know that Dynomax has a part number for each piece.