I have a stock header and exhaust. Question, will a 2.25" inlet/2.5" outlet be too big for the stock exhaust? My cat's insides are loose and I need to replace it. I'm not looking for power, just a fix to my problem.

 

im not sure of the size of stock piping but u know u could easly go out a measure the sive of the pipe before and after ur cat and this would answer ur own question.

 

Well I don't feel like taking the rusty cat bolts off and wasting time plus I know that the stock stuff is smaller than the straight pipe. I'm just wondering if anybody has tried something similiar to know if it's too big of a difference or if it'll be fine.

 

this is what my friend did when he was low on cash

.remove the exhaust from the end of the header to the muffler
.take a saw and cut off your cat leaving the flanges attatched to your downpipe and b-pipe
.buy a length of pipe that is more or less the same thickness as your flanges and weld it on.

or what i did was have crush bent 2 1/2 piping installed from the cat to the muffler. it sounded stock, fixed a bunch of leaks i had on the factory welds, and for $70 bucks it didnt dent my wallet

 

I don't know how to weld or I would just make my own non-ghetto straight pipe. And I can get one made for less than $70 and my exhaust is perfectly fine so no need to mess with that. I'll probably just have a local shop make a custom straight pipe that'll be the right diameter for me I guess.

 

it will work, i did it to a 95 civic si, did make it alot louder though, and gassy smelling

 

How big of a difference was in diameter compared to the header and exhaust?

 

obviously the piping diameter if different, but the connecting flanges bolt to the same holes. The OEM exhaust is somewhere around 1.9" on a teg IIRC, so its not much difference. Other than not being legal, helpful to your car or the environment, ebay cats will fit and fill in the space.

I have one bolted between my DC sports and the WS2 just fyi. And before the WS2 it was bolted to the DC and OEM

 

Ok cool well yea it's not too big of a difference. If getting a custom one made locally is expensive I'll just get the ebay one then and see how it works out.