Whats up all....

Pretty forward question I think.....

Been shopping around for a exhaust for my R....

Noticed that most systems are specific for either a USDM or a JDM R. I guess my question in where does the difference between the two start. Is it from the header back or are the mount points under the car different as well. If I have a JDM Spec header and test pipe/cat, will a JDM spec exhaust bolt up clean. I would imagine that a mix-n-match between the two would need some fab to fit, which I'm trying to stay away from having to do.

Thanks for the feedback and please throw some suggestions my way for a proven systems you all like.

 

The jdm header has a 2.5" collector and the usdm has a 2.25" collector.

 

Thanks bro. I knew that was one of the main diff. Looking more for if/what the length and mounting diff are between each part.

 

JDM spec exhaust has longer B-pipe and shorter cat - cat is 12" long. Now, if you have JDM header and test pipe, which fit USDM spec exhaust, than you will need to shorten that test pipe to fit on JDM spec b-pipe.

 

the stainless steel jdm ITR header is also about 2" longer than the cast iron usdm ITR header. in addition to the different piping diameter at the collector flange, the clocking on the jdm ITR flange is also different.

i believe that there may be a difference in the b-pipe lengths, too, because the jdm ITR catalytic converter that i have is considerably shorter (about 4") than my usdm ITR catalytic converter. however, this is only an assumption based on a side-by-side comparison of both my OBD2 1998 usdm ITR catalytic converter and my OBD1 (no secondary O2 sensor bung; possibly for a 96 spec) jdm ITR catalytic converter. obviously, the diameters of both catalytic converters are also different, with different clocking at the flange that meets the header as well.

this is what i've been able to gather so far; hope this helps.

 

Good info thanks guys......if you learn more throw it my way.

 

A jdm length header such as the ITR, T1R, Toda etc, are all 3/4ths of an inch shorter than a USDM header.

While you will a 16.25 inch catalytic converter to bolt up a usdm header and usdm exhaust, you will need a 17 inch cat to bolt up a jdm header to a usdm exhaust.

A JDM itr exhaust, however, is much longer, to compensate for the shorter catalytic converter that come on the jdm spec itrs, being about 12 or 13 inches long. This way, for the 4 extra inches needed for bolt up, the jdm b pipe is extended 4 inches.

Same thing occurs when dealing with 94-01 LS/GS/RS, 97-01 USDM ITRs, and 00-01 GSRs as opposed to a 94-99 GSR, whose header length, cat length and b pipe length are all different.

 

why do you think the USDM's cat is bigger and the collector is smaller?

 

I'm thinking it has something to do with US emisions regs?

 

yea US emissions are more strict, than lets say Europe or Asia.

Its just like exterior car parts. A JDM ITR front end in Japan is perfectly legal because their safety standards are not as strict as our standards. That makes a JDM front illegal to have in the US (because of their flimsy radiator support). Its fine for Asia, but when bringing imported cars to the US, the safety standards must be higher in order to meet the US expectations.

 

I understand the clocking of the flange is different but which of these two statements are true? Is the JDM 4-1 SS header shorter or longer than the USDM counterpart?

Mainly interested because I want to weld a flange onto my testpipe but I don't know whether I need to lengthen or shorten for it to work.

 

sorry im all late, nice thread btw..

i am here to learn an understanding on this also. Right now i'm running a JDM ITR with i believe a JDM cat (small). with a CTR cat back.. all JDM because they bolt right up.

my problem is, i need a USDM cat for ref purposes. Is there something the same size of the JDM cat that is USDM? And of course bolt right now. Trying to stay away from welding and cutting like thatDC2guy.

 

you could buy a magnaflow universal and do all the cutting on the cat itself rather than the exhaust.

 

i need something california street legal.

nvm, found something that i think would work.. thanks!

http://www.bestinauto.com/Magnaflow-...Converter.aspx

 

good info thx

 

I'm glad somebody is shining some light on this issue because I'm in the same boat.

I have a JDM ITR 4-1 header mounted, I'm about to order a JDM ITR B pipe and JDM ITR muffler. I'm talking to Kteller.com about an OBD2 Smog legel Cat to see what is the best route. Once I get an answear from Kteller. I be happy to post it.

 

Kteller got back to me and they said the standard carsound universal cat is 13" long. Your choice for a 2 or 3 bolt flange and they can supply an O2 bung.

 

we can customize any cat to any length and setup you need.. its just getting all the details.. some supply us with carsound cat part number to start, others just go with what we have, email is easy and i hope we can help

 

Hey K Teller do you offer a 2.5" piping kit for jdm itr header with JDM cat Catback for a dc2 integra 3dr ? maybe something resonated too

 

please email me, we're limited to how much 'pushing' we can do on here at the moment. Please email me for sales specific questions

 

JDM is always better. u know its Jazma