I am planning on buying and h/e soon and i was just wondering on something. If I buy a exhaust with 2.5" piping diameter., will that bolt up to my factort cat converter? And If I get a header with a 2.5 inch collector does that mean my cat aslo has to be 2.5 inch? Im confused... I want to buy the type 1 racing exhaust with the jdm 4-1 with 2.5" collector...Will this bolt up to my factory cat or do I need a new one?

 

no, i dont think you absolutely have to have the same size cat as the piping.. the cat will become the hindering peice in the exhaust tho. if the header is coming in at 2.5, then then has to condense down to whatever the stock cat size is. one solution is a high-flow cat.. or you can just deal with it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Zak8022 &raquo;</TD></TR><TR><TD CLASS="quote">no, i dont think you absolutely have to have the same size cat as the piping.. the cat will become the hindering peice in the exhaust tho. if the header is coming in at 2.5, then then has to condense down to whatever the stock cat size is. one solution is a high-flow cat.. or you can just deal with it.</TD></TR></TABLE>

But how can you bolt up 2.5 inch piping with the stock piping size? Doesnt that mean that I must have 2.5" all around

BTW, I'll prolly get a high flow cat anyway...Know of any good brands that will still pass emisions?

 

carsound cats are good - my buddy (garth) is actually selling one...only slightly used

see this thread https://honda-tech.com/zerothread?id=1111406