Ok,

I have been discussing this with a shop and I am confused. I have an 00 Si with the stock B-pipe. I am wanting to run a JDM header whether it is the OEM header or the DC.

My question deals with the length of the JDM style header itself. There is a question about having to extend the B-pipe to make it work with a JDM cat and JDM header.

Is this accurate?

cliff notes:

1. Is the JDM header longer then the US spec header?
2. besides changing the flange to make it fit to the flange of a bigger cat is there an extension that needs to be made to the b-pipe?


If anyone has experiece with this on their ITR or Civic Si, I would appreciate any help.

This forum is the most helpfull that is why I posted here, if it is in the wrong place please move.

Thanks.

 

All thought this does not belong here... I'll take a shot.

JDM style header Is longer then usdm cast iron manifold
Your going to need a custom cat that is shorter.

OR you could just buy my setup and be done.

 

Yes, the JDM header is approximately 1" longer than the stock unit. I'd suggest just getting a custom high-flow cat that is the proper length to bolt between the JDM header and the stock exhaust. I'd also suggest that if you plan to keep the stock B-pipe, you remove the severe bottle-neck at the cat/B-pipe flange and replace it with a tapered adapter.