Hey guys, I have a 2000 Civic Si and I need some help with exhaust stuff (hence the thread). Right now:

Motor is stock and probably won't get anything more than an engine overhaul in the near future

Exhaust
-Header is stock
-Resonator test pipe to replace the cat
-2.5 inch Apexi N1 replica (effectively straight through with a 14" oval resonator in the beginning and a glass-pack can type muffler at the end)

The problem I am having started when I removed the cat, the exhaust note got a lot louder in the mid RPM's especially when unload like climbing a hill. The exhaust itself was on the louder end of tolerable before I took the cat off but not the mid RPM drone is deafening.

So the question is how to fix it? I am not opposed to getting a different exhaust but I'd rather not spend $500 on a bunch of bent tubing but I will if that's what is truly needed. Is there anything I could add to quiet it down, like welding a larger resonator in place of the small one that it came with?

Thanks for the help!

 

Put ur cat back in.

 

The cat in my car barely passes CA smog which is why I took it off. If I were to continue using it I would have to buy a new one to pass (and only the OE cat can pass with a stock ECU). A new cat from Honda is $900 dollars so I would rather not put the cat back in.

 

No one?

 

Without a cat it won't pass emissions at all, so that statement is a bit confusing. If the noise of your exhaust bothers you, put the cat back in. Less power, less noise, less emissions.

 

Allow me to clarify.

I want to run my car without my cat so I do not damage it any further so that when I DO need to get the car smog-ed I will reinstall the cat (which still passes smog because I haven't been using it yet).

In the mean time I will be running my car without the cat and the noise has been bothering me. So if anyone has an idea on a solution that does not involve putting the cat on that would be much appreciated.

 

Thanks for the help everyone!