I fabbed up a new exhaust 2 weeks ago and have alot of resonance issues. My set-up is as follows: true 3" duals, stock manifolds, dynatech cats, magnaflow x, 2 DNA mufflers, single 4" tailpipe exiting in stock location. Exhaust basically looks like a 2500hd system with the x under the pass. floor and the muffs in the stock location. Engine is 6.0 with hot cam. What exactly causes resonance and any suggestions on eliminating all or part of it? Thanks.

 

My novice guess would be you're running too large of pipe for your mods. Dual 3" with a 4" tailpipe sounds like overkill. Especially with stock manifolds. Your exhaust isn't going to flow as fast as it would if you had smaller pipe. If your pipe is too large for your setup, the gasses are going to cool which means they're going to travel slower and, again, my novice opinion, would be that's where your resonance is coming from.

 

i agree. step it down to 2.5" piping before the mufflers. chevy's are bad about resinance. a real expensive solution to your problems would be corsa exhaust...

 

exhaust is too big for your current mods. if you were going to go with a big s/c or turbo setup, then the wxhaust would be ok. 2.5 inch duals with a hooker or imco muffler will help with the resonance. or like said above, get a corsa.

 

I agree with everyone's suggesstion that the exhaust is too big with my current combo, but I do plan on supercharging this thing down the road. I can understand the resonance when the pipes are too big but explain why this doesn't happen in stock applications, like the 2500hd's? Short of fabricating smaller pipes or more hp do I have any other options to decrease the resonance? Thanks.

 

HD's have more cubes, and ive heard that the right side of the "duel" muffler is a dummy. if you actually look into the muffler its almost blocked all the way off while the other side is pretty open. factory muffler is also very quiet so that takes care of alot of it.

other options...install 2 long bullets before each muffler. that MIGHT help. it will definately make your exhaust quieter though.