I just picked up an 02 ex yesterday and have an exhaust question.

It came with an unknown brand intake, Megan Racing header, custom downpipe (no details about it unfortunately), removed cat, and a Magnaflow muffler with a 4" tip. I haven't had it on a lift yet to check the piping size, but it appears he replaced it with 2.5".

I'd like to go back to stock exhaust, but I'll probably keep the header..

First question...would the exhaust from an 04 Civic sedan be a direct bolt on? I've emailed for additional information, but that is all the listing says.

Second... There is a bolt in the header pictured below. Should there be an o2 sensor there?

Thanks in advance for any help!

 

Why do you want to change the entire piping back to stock? I'd say keep the upgraded exhaust and get a quiter muffler. Also, yes it looks like an O2 sensor is supposed to go there

 

I plan to keep the car naturally aspirated, and I feel the 2.5" is too large for that. I'll get the car on a lift and measure the pipe before making any changes.

Any recommendations on a quiet muffler? I'd rather keep the noise level pretty close to stock.

 

Get a resonator and a catalytic converter. Without those, your car probably sounds like a bunch of angry bees in a coffee can.

As for a direct bolt-in replacement, you may be able to run an EX downpipe, cat, and cat-back on the car (year is irrelevant, as long as its a 2001-2005 EX model).

 

The previous owner told me it had a customer resonator, but I haven't seen it yet. The car actually sounds good, I'm just not into the big loud exhausts. I am picking up a cat, but first I need to see what size piping I have. Maybe I'll just pick up the cat for now, then go from there.

Thanks for the replies!