I know this has been covered many times...

What key words do I need to use for the search!?!?

but no matter what I look up, I come up empty handed.

Sorry, just venting.

Anyways, this will be answered easily.

What is the diameter of the JDM ITR B-pipe? 2.25" or 2.5"? 60mm or 57.2mm?

Any reply will help.

Thanks,

 

i think its 2 3/8

 

Thanks,

So the aftermarket exhausts should have the bigger diameter than the stock jdm.

 

not nessecarily. Apex'i World Sports and N1s are like 2 3/8''. I'm pretty confident that the USDM exhaust is 2.38''...so..would the JDM one be larger? Or is the U.S. one not 2.38?

 

Just did a quick research

Stock Integra Type R 2.25 57.2
Stock Integra Type R (JDM) 2.25 (ID) 57.2

The USDM and the JDM one have the same diameter.

 

Yes, JDM and USDM exhausts are the same size. The only difference being the different b-pipe length.

After the bottlenecks are removed, the exhaust is plenty adequate in size unless you're making a lot more HP.

 

Bottlenecks being cat, right?

 

Not exactly. The OEM B-pipe and muffler necks down the piping a bit. If you have one off and look at it, you'll see what I mean.

 

Is there anyone that makes something similar to the OEM b-pipe in shape but with a wider diameter?

 

I think there used to be one or two, but not sure if they are still available.

The OEM B-pipe bottleneck is easy to take care of though. A muffler shop did it for me for about $30.

Personally, I'd like to find a good quality axle-back again. I had a SS Comptech back in the day, but I stupidly sold it.

 

Jdm itr is 2.25 (Od) not (Id) i just went through this with Dave at smsp !

Usdm its even smaller sorry!

 

I am also interested in this info..

I want to do a JDM ITR header, and OEM USDM ITR Muffler. What do I need to fill in between the header and muffler?

is the JDM b pipe the same diameter as the USDM b pipe?

the parts listed above may go on my 99 GS-R coupe.


BTW: I will be selling my Comptech muffler and Comptech B pipe soon if anyone is interested.

TIA!!

 

What's it matter? The muffler will be the bottleneck anyways. JDM vs. USDM B-pipe will be of little consequence.

And double whammy on putting a forsale post inside of a GSR question.

 

I got the muffler will bottle neck anyway. I dont understand what youre saying about the B pipe.


I said it will be for sale soon. No thread, pics, or even price are up man.

 

If you are wondering about B-pipe length, this question has been answered 100's of times over (GSR or not).

P.S. It all depends upon cat length.

 

usdm and jdm b pipe are the same length, the cats are different lengths, to accommodate the 98 spec jdm itr exhaust manifold

the bottle neck in question on the b pipe is right before where the b pipe connects to the muffler

people always argue the size of the piping between usdm and jdm, but even if there is a difference in size it will never make a difference in power, because if you are using a stock jdm itr exhaust mani, cat, b pipe and muffler your motor is also pretty stock, so this exhaust will not hold you back at all in any way

 

sweet, so if I do a JDM ITR header, USDM ITR b pipe, USDM ITR muffler, what cat size & brand do you recommend to complete the setup?

 

you will need a jdm length car, if that is all your doing id recommend a oem jdm itr cat