im lookin to pick a jdm itr 4-1 soon, i was wondering could i use my stock us itr cat, whould it even fit, will it block horspower, only other mods are cold air intake , with stock b pipe, and spoon n1


if bad to use stock cat what should i use

 

You would have to modify/hack the collector off and fit it with a 2.5inch version. Personally I would just buy a 2.5inch hi-flow cat and use that since they are dirt cheap. A 2.5inch hi-flow cat will bolt up to your stock b-pipe with a special donut gasket. Then, if you ever needed to pass tech, you would have the unmolested USDM version to mate to your stock exhaust

 

Isn't the US cat too long, in addition to the smaller diameter?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Splat &raquo;</TD></TR><TR><TD CLASS="quote">Isn't the US cat too long, in addition to the smaller diameter?</TD></TR></TABLE>

I believe the "hacking" process would take care of the length problem since it is only buy a few inches. My shop was ready to rock on mine with a JDM 4-1 header then I decided to go with an aftermarket piece so I could retain the stock one for future needs.

 

Yep, you're probably right. But considering the OEM cat is ungodly expensive, I'd suggest your route as well. When I had my JDM 4-1, I bought a universal cat from Jeg's for about $50, and had a local shop weld on the proper inlet/outlet.

Last time I checked, the same cat was around $150

 

^^^^joo got it mang . $100CAD for a Vibrant cat with the collectors welded on. I wouldn't even want to know how much the OEM piece is from Acura

 

great info guys


im just getting an aftermarket cat, what size? 2.25 to 2.5? how long?

thanks alot

 

2.5" in/out. Don't recall the length, I'll see if I can find out what I bought back in the day.

 

thanks alot

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by white rocket &raquo;</TD></TR><TR><TD CLASS="quote">I believe the "hacking" process would take care of the length problem since it is only buy a few inches. My shop was ready to rock on mine with a JDM 4-1 header then I decided to go with an aftermarket piece so I could retain the stock one for future needs.</TD></TR></TABLE>

I am Afraid not.. I have done this Jdm header and a usdm cat but there is a huge diffrence in length and unless you are good at fabrication and welding i would not recomend it.

How to:
Cut off and install a 2.5 flange on the usdm cat.
install the header and cat in the car.
Drop the mid pipe assm and chop the flange off right behind the weld.
cut the mid pipe to remove the "bottle neck, the only place where the exhaust is not 2.5" remove enough materal from the inside of the flange so it will slide over the 2.5 pipe and align it all up then weld it.
Not easy but i do have the only stock 2.5 ITR exhaust around.

 

Perhaps it is a little more work than I let on. I stand corrected.

I guess I was looking at the fact that the OP asked if it was "possible", which it is. I still stand by my original recommendation of buying another 2.5in. cat and leaving the OEM 2.25 one alone.

 

This should work - search http://www.jegs.com for this:

Magnaflow 642-94306 2.50'' In/Out Catalytic Converter

You'll also need an O2 sensor bung. Take all this to a shop and have them weld/fit it up.

*Edit - found my notes from back in the day. You need something around 14"

 

Jdm ITR cats are 12" long. usdm are 16"

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rene M &raquo;</TD></TR><TR><TD CLASS="quote">Jdm ITR cats are 12" long. usdm are 16" </TD></TR></TABLE>

Cool.

The cat I used when I installed a JDM 4-1 header while keeping most of the stock ITR b-pipe (cut off the first restriction) was 14" long. The shop welded on the appropriate mounts, and off I went.

 

Buy a Omni Power test pipe. It's adjustable;
http://www.kingmotorsports.com...t=462

Worked out perfect for me