https://honda-tech.com/zerothread/2198291

TIA!

 

bump for some insight!

 

ttt

 

it depends on what kind of header u are running. cause all b series headers have different flanges angles.. for directly bolt on, if u are running 99-00 civic si header , stock or aftermarket.get the cat converter from 99-00 civic si. if u are running integra ls header.get a LS cat convter or u can get any b or d series cat converer and have a muffler shop cut and welded for you.thats what i did.

 

Best bet is to buy a universal type Magnaflow cat in the desired length, then have a muffler/welding shop install it. Ask them to specifically add flanges to keep it bolt on, bolt off in case you ever want to swap it out again for the test pipe for track days, etc.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crazyguy &raquo;</TD></TR><TR><TD CLASS="quote">it depends on what kind of header u are running. cause all b series headers have different flanges angles.. for directly bolt on, if u are running 99-00 civic si header , stock or aftermarket.get the cat converter from 99-00 civic si. if u are running integra ls header.get a LS cat convter or u can get any b or d series cat converer and have a muffler shop cut and welded for you.thats what i did.</TD></TR></TABLE>

Hey crazy guy, thnx for getting back to me. I know my DC headers are for a GSR, but what year is what I'm not 100% sure on. It's a 2.25" collector with a 2 bolt flange which bolts to my test pipe, which is 21 3/4" long with a 3 bolt flange which bolts to my midpipe etc. I did some more research and it doesn't seem like anyone builds a bolt on 21 3/4" cat, so I think I'm going to go with B18C5-EH2's suggestion of just grabbing a universal cat and add some extensions and weld the flanges... easy and done.

Side question, lots of people ask if an OEM cat is better than an aftermarket cat (better in the sense of reducing emissions), anyone actually know?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SPD DMN &raquo;</TD></TR><TR><TD CLASS="quote">Side question, lots of people ask if an OEM cat is better than an aftermarket cat (better in the sense of reducing emissions), anyone actually know?</TD></TR></TABLE>

Honestly the OE cats are superios to all others. They're the only ones that I know of lasting 10+years and still keeping cars passing the emissions tests where they put thge sniffer in the tailpipe.

Aftermarket cats typically last 3 years or so for cars that have to pass sniffer tests.

...then again new OE cats cost between $600.00-$1,200.00 whereas after market ones that are still good can be more like $150-$350.00.