I just bought this header and want to install it on my car. Will the s2000 flange work with a stock cat? where would i order the 2.5 in donut gasket? also what kinda of gains could i expect? i have an ls/vtec with pr3 pistons and stock gsr head with skunk2 Im, chipped ecu, intake and exhaust. I was running a U.S dc 4-2-1 before (yea i know, crap) should i expect a noticable difference? thanks guys

 

you could gain up to 20 hp.

 

correct, you will need a 2.5" donut flange (one from an s2000 would work), but you won't be able to use your stock cat because its too small. you should consider getting a 2.5" carsound cat. the donut flange should be available from your local honda dealership, places like inlinefour.com also sell them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by david555 &raquo;</TD></TR><TR><TD CLASS="quote">you could gain up to 20 hp.</TD></TR></TABLE>

you are a cerified Jabroni. 20 hp? LOL. you'll make some power up top, but, not much. maybe 3-4whp. and i don't think that its worth it because you'll smash it in the first week and lose a bit of exhaust flow which will probably end up making the same hp as an undented 4-2-1. i would not be suprised if you put a 2.5" collector on the 4-2-1 and made roughly the same hp as the dc jdm 4-1. yes, its your best bang for your buck, but, only if you don't mangle it, and don't drive it in the winter. dc header rust terribly. g/l

 

yea 20 hp did sound like a lil too much. The only reason i actually got the header is because someone traded me staight up for my 4-2-1. so i thought it was a good deal. anyone else have an opinion?

 

What I did was bought a 2.5" s2000 donut gasket from a honda dealer for like 23-ish dollars. The stock cat wont fit, and I bought a 2.5" in and out carsound cat from ips racing. Take it to a muffler shop and they can weld on flanges to the cat so it will bolt up to your current exhaust system.

 

that sounds like a good idea. So the 2.5 inch carsound cat will still work with my 2 and a 1/4 piping right?

 

The muffler shop should be able to make it fit.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AllM0tadc2 &raquo;</TD></TR><TR><TD CLASS="quote">that sounds like a good idea. So the 2.5 inch carsound cat will still work with my 2 and a 1/4 piping right?</TD></TR></TABLE>

You can order a 2.5" cat from SMSP that will be a direct bolt-on. He can also supply you with the donut gasket you need.

 

will my 2 and 1/4 piping be hurting me?

 

It won't be ideal, but a simple and easy upgrade you could make to your 2.25" exhaust is to install a a 2.5" -&gt; 2.25" tapered adapter at the flange that connects to the cat, thus providing a smooth transition between the two pieces.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan &raquo;</TD></TR><TR><TD CLASS="quote">You can order a 2.5" cat from SMSP that will be a direct bolt-on. He can also supply you with the donut gasket you need. </TD></TR></TABLE>


thats what i did

 

You can buy a Donut for a CRV, it's cheaper than a S2000.

https://honda-tech.com/zerothread?id=1067321

 

great info thanks