Headers = resonance?
 

Title says it all. I had a Flowmaster cat-back and stock manifolds. Sounded great outside and quiet inside. Added headers and random tech cats, now it sounds incredible outside but I picked up a fair amount of resonance around 1800 rpm's. From everything that I ever read, I didn't think headers would make it resonate. Guess I was wrong. Corsa anyone?

Re: Headers = resonance?
 

What headers are you running?

Re: Headers = resonance?
 

SSW.

Re: Headers = resonance?
 

I wonder if a set of corsas would mellow them out some? Your not running a resonator correct?

Re: Headers = resonance?
 

The Flowmaster has a resonator built in. When the exhaust shop welded everything up they had to shorten the cats as well as the inlet pipes to the mufflers. I know I'm grasping at straws there but, the whole thing seems strange.

Re: Headers = resonance?
 

Hmm dont know... but at some point im about to do the same thing with a set of Jeals and a corsa system. I would hope to not pick up any resonance either.

Re: Headers = resonance?
 

i ahd a set of flowmasters on my black car with headers and no cats . once i adjusted the hangers (those spring things that hold up the exhaust ). mine were too loose and the muffler tips so that there was a min. of 12mm below rear opening the inside of the car got alot quieter. how i found out was the passenger muffler moved and got real close to the opening which made it very loud inside the car.hope this helps

Re: Headers = resonance?
 

once you have it, can be a real PIA to get rid of, if you can do anything about it at all. not what you want to hear, i know. i've built a bunch of different headers & to a lesser extent complete system's with a fabricator friend of mine for engines i've built. to say your scenario seems strange, that's just the beginning of the whole exhaust world. IMO the most mis-understood piece of the higher performance food chain. very few, if any absolutes. it's kinda a moving target to a degree. in closing i will say the vast majority of individuals still go too big & that for sure will not help resonance, again IMO.

Re: Headers = resonance?
 

I bought a set of Flowmaster mufflers and installed them in place of the stock '90 mufflers.
Resonated like a bad dog at highway speeds in 6th gear.
:thumbsdo:
The drone would drive you nuts.
It also burbled and popped on deceleration (which I didn't mind).
I put a complete Flowmaster setup on and the resonance and pop are pretty much gone.
Next step will be x-pipe in place of the resonator later when the weather warms a little.
Don't want to argue with the Smog Nazi's so no plans for headers or removing/replacing the cats in my near future.

Re: Headers = resonance?
 

usually a chip done properly for headers, exhaust or both will clear that up a ton. you got chip?