i have DC headers, 2.5 inch piping, with no cat, and a magnaflow muffler 14805 or 14807. I was told the other day that if i put a cat on my exhaust it would quiet it down a little. The only reason i want to quiet it down is because i got pulled over for it the other day and i am really tired of getting pulled over. Just so a cop can find a bull **** excuse to pull me over then come to my window and ask if i have any drugs in the car and they ask if they can search it.(They dont find anything... Ever cause i DONT mess with drugs.)

 

Ok, that magnaflow muffler with dual 3+ inch tips.. that will get you nothing except bad attention, it looks to me as if it's made for noise.

I had a Greddy SP on mine back in the day (cat back) stock header/downpipe/cat though ... it did make some noise, but most the time it was reasonably quiet unless I romped on it. I never got pulled over for my exhaust once I put it on, previously had a Hyame with a 5" tip ..

Recommendations: Apexi N1 , OBX Twin Loop, RS*R, Greddy SP2

You'll want to get a universal muffler and have a shop put it in for you, if you want quieter still, then yes have the shop put in a high flow cat for you at the same time.

I have in my lude now, stainless header, test pipe instead of cat, and cat back vibrant exhaust.. the vibrants garbage, fit is horrible and its loud as ......

OBX Twin loop will likely be what I go with because its cheap, and appears to have a good exhaust tone (Youtube)

 

long resonator, catalytic converter and a better muffler. or spend the money and get a good quiet system that is complete and ready to bolt on.

 

Yeah if you don't have a cat, it will make a bit more noise for sure, not to mention smell bad and kill baby penguins....

Adding a good cat is one thing, and ensure you have a good resonator, 18" or so seems pretty normal for the prelude, maybe a second one of a different size to cut down a different "frequency" of the exhaust notes.

Honestly if you go to a decent exhaust shop and tell them you want to quiet it down, they should be able to do it.

Otherwise, get a muffer that can use a silencer in the end. I have one for my WRX, and love it for long trips to cut down on drone.

 

Put one of these right off the cat, but your diameter. The longer and bigger the lower the tone. You should get .5" bigger though because the baffles cause a .25" choke point. Its a 1/8th" high around the inside of tube. A shop can flar piping up to .5" of a inch. Im running a true 2.5 header back.

http://www.summitracing.com/parts/imm-87519cb/overview/

Things are monsters lol, the 35" ones at least in size i mean. I have one thats going on mine. This exact one ^

 

Get the largest diameter pipe you can from the down pipe to the back. It'll help produce a deeper sound rather than loud popping sound, if that makes any sense.