JDM H22A Downpipe- What Catalytic converter connects?

[wisdom62]

I'm about to install my H22a in my 90 accord. I've figured out everything except for for the exhaust. I have the stock header and downpipe for the H22a and I will be going with a 2.5" custom catback exhaust.

I only need to know what catalytic converter will bolt up to the downpipe? I'm assuming a 94 prelude vtec catalytic converter should work, and I might have to drill out the holes slightly.

Is that true? Also there might be a chance that I received the BB6 (5th gen downpipe) from HMotors instead of the 4th gen one. It does look shorter than it's supposed to be and there is some marker written on it saying bb6.

Once I verify that, and if it is indeed the 5th gen downpipe, then I assume I can by a 5th gen prelude catalytic converter which should bolt right up to this downpipe correct? I can take pictures of the downpipe and flange for reference.

Any help on this would be greatly appreciated.

[Domesticated]

When I had a stock header I used the Accord downpipe and Accord everything else bolted right up. When I switched to a Feel's BB6 header I had my cat cut and extended to fit. The BB6 downpipe is over a foot too short.

[wisdom62]

I didn't think the F22 downpipe would connect to the h22 header.

Right now It looks like I'm going to just have to get a cat and extend it to the H22 downpipe which I'm pretty positive it's a 5th gen one, as it is a foot shorter.

I've been looking at aftermarket headers but don't have the money for one now.


Should I still be good to go from the 2" downpipe to 2" catalytic and then to 2.5" catback? I would think this would free up some flow.

The first muffler shop i went to said I that it's not legal to enlarge the pipe diameter from the header to the cat. i was trying to get the 2.5" collector mod done.

[Domesticated]

The bolts holes don't line up, but everything else does. Just drill new holes and either use a bolt and nut, or tap the holes for a screw. Yea, that should work. I don't know how your local laws are, but around here we don't have exhaust laws except for noise level.

[ssondubs]

I'm using the JDM header to a USDM Downpipe to my stock CB7 cat converter. It's working great but I'm sure it would run better with a larger sized cat