I'm in the process of getting a JDM 4-1 header for my ITR. I've heard that the JDM ITR muffler is the exact same as the USDM ITR muffler.
I want to keep the car looking (and sounding) as OEM as possible. I plan to get the JDM 4-1 header, JDM cat, and JDM b-pipe. Will the JDM ITR b-pipe bolt on fine to the USDM ITR muffler? Theoretically it should since both JDM and USDM have the same muffler?
Also, will the US O2 sensor fit in this setup?



[Modified by 98R-1144, 9:49 AM 6/13/2002]

 

I had heard that the JDM muffler is shorter, but is hearsay...

Come on peeps, someone has the answer.


well... TTT for ya

 

I don't think the USDM O2 sensor will work unless you weld in a O2-bung on the JDM cat. I think USDM comes with OBD2... JDM isn't OBD2, is it?

 

i'm not sure..
come on someone has to know!
otherwise i'll end up getting the JDM 4-1 + high flo 2.5" cat..mated to stock bpipe
you think that will still yield good power, despite the bottleneck?

 

Id actually like to know the same if a jdm 4-1 with 2.5" cat will yield little hp gains with the stock usdm exhaust.

 

JDM b-pipe is has a slightly bigger diameter(close to 2.5) than the USDM. JDM is also about 4.5inches longer to accommidate the shorter JDM cat. In order to make it work w/ obd2, just have a muffler shop weld in the second bung for the 2nd o2 sensor. Assuming you are using JDM 4-1, JDM cat, JDM b-pipe, and USDM muffler.

 

Please provide evidence to back this claim.

Thanks.

 

bump

 

Tamotsu Horikoshi's article on the Type R in Japan states the exhaust is 57.2mm (2.25")


[Modified by SurferX, 7:33 AM 6/14/2002]

 

I think what he meant was the JDM B-PIPE is 2.5"..but the JDM muffler is the same as the USDM muffler (2.25").
Now would it be worth the price to get:
JDM 4-1 --> JDM Cat --> JDM B-PIPE --> JDM/USDM ITR Muffler
or just stick with my original planned setup:
JDM 4-1 --> High Flow 2.5" Cat --> tapered 2.5 to bolt on to USDM bpipe(?? I've seen them before..not sure who to get it from) --> USDM B-PIPE --> USDM ITR Muffler

 

I have seen them both side by side, they are the same diameter. Jdm one is longer though.

 

Nope. Both are 2.25".

 

So the JDM cat essentially has a 2.5" inlet (from the header), but the outlet is 2.25 to mate w/the (longer) JDM b-pipe?
If that is the case, I would probably just get a high-flo 2.5" cat and find a tapered 2.25 end to ease the bottleneck into the bpipe.