Have full ZZP header w/ CAT and Resonator, quite obnoxious sounding and way, way too loud.

Was thinking of adding a second resonator, maybe vibrant's ultra quiet series but I just crawled out from underneath my balt and their isn't room to add much of anything.

Could add a 2.5 restriction at the gasket, but thats pretty ghetto and likely to mess with scavenging and pulse width.

Vibrant has a racing exhaust, Vibrant Performance ::.

Looks like I could shoehorn it between the gasket and the existing resonator...but how effective it would be is a matter of debate.

Anyone have any solutions?

 

If I were you I'd get a 2.5" LNF or aftermarket. 3" is overkill for what you have. That will quite it down. BUT... since you already have the exhaust you could replace the muffler. General rule of thumb is the bigger the muffler and resonator, the quieter. Magnaflow's are very loud, Dynomax makes a nice muffler, Stainless Works makes a nice muffler.

That should do it. 3" exhausts on a 4 cylinder are usually loud.

 

That Vibrant piece won't make a difference. New muffler and res and you'll be happy. Just make sure the res is over 20 inches.

 

Alrighty, thanks for the insights!

On the cheap end, would a 2.5" restriction quiet it any?

I was thinking something along the lines of this 2.5 to 3"SS reducer welded to this SS flange

I'd shave the reducer on the 3" end down so it would slip into the straight pipe and taper gently to the new flange at the DP/CAT back union. It would be a smoother transition than my old ZZP DP from the SC Kit, and basically very close to the same location. The added backpressure should help down low but will it quiet down the racket?

 

I will try and find an exhaust article for you, if I do I will post it. You won't need more than a 2.5" exhaust until you get past 300whp. Also, the benefit would be having low end torque. I'd do that. There are really nice 2.5" exhausts out there for our cars. I don't want to try and sound like a hypocrite by saying this because personally, I need a 3" maybe you and I could work out a deal, I could buy your exhaust from you and you could then get a 2.5" exhaust. Lol, I'm not trying to make you sell your exhaust. Just trying to help you out.

EDIT: Found the exhaust thread link

http://www. cobaltss .com/forums/showthread.php?t=2214

There is a space by the CobaltSS, it won't let me post it otherwise