I have a civic si 2006 right now with a greddy exhaust system. It sounds nice but I've heard of people doing resonator deletes or muffler deletes and getting nice sound but im not sure if that damages any other part of the car.

 

doing that does not give you a deeper sound

 

Think of the size of a flute, and how high of a pitch of sound they produce. Now think of the size of a tuba and the sound it produces.

If you want a deeper tone from the exhaust, you want a larger diameter pipe. To complete the effect, choose a resonator that filters out mostly, if not entirely, high frequency sounds, and then use a muffler without baffles.

Just deleting the muffler will only make it loud. Just deleting the resonator will produce a raspy, dissonant, tone. Neither will produce a deeper tone, just more noise.

 

I have a 3" full-race exhaust and it has a pretty deep note. If you end up swapping out for something else. Its also very quiet until you stomp it.

 

invidia q300 catback exhaust is really deep and sounds amazing if ure looking to change the exhaust it will deff be deeper then the greddy.. deleting resonators will make it more raspy and just alot louder

 

Have you thought about a testpipe?

 

Vibrant has a nice system if you're doing 2.5"

 

Do you have the greddy elite cat back? I had that and it was less loud then the oem si exhaust. Invidia if you want deep, skunk if you want LOUD, vibrant if you want an in between. Test pipe is a good idea also.

 

Matter of fact add a intake problem solved. Want even deeper ad a header.

 

if you just want sound and want cheap. Got to an exhaust shop and ask them for a 2.5 inch midpipe with the flanges so you can bolt it to your stock muffler. Basically a straight midpipe, no resonators. It sounds better, but in vtec is a little ricey. I'm running the set up in my car, and around the city under 5k, it sounds pretty good

 

Do not get rid of the resonator. That will give you the opposite type of sound of what you're looking for. As already mentioned, get a bigger exhaust, and make sure it has a resonator (some exhausts for turbo setups don't).