I'm replacing a test-pipe with a high flow cat on my 93 ex coupe with a b16a3 in it.

Wondering what size to get? 13'' or 16''?

I was looking at the magnaflow ones.

 

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I would be interested in this as well, I would love to find a legal high flow cat.... cuz what good would a free flowing intake, header, and catback exhaust do with one restrictive element in the middle? I think that upgrading the cat would help open some good power. I have intake and exhaust now, and I hope to do header/high flow cat soon. BTW are those magnaflow cats CA legal?
good luck in getting some info

 

i'm having similar problems i think: https://honda-tech.com/zerothread?id=1228669

ok i measured the ITR 4-1 header-downpipe vs D16Z6 header-downpipe today, and they are exactly the same length! I was surprised too. So back to the test pipe/highflow cat, get the one that is the same length as your current test pipe/highflow cat (not sure what length).

 

Thanks....I'm going to get the smaller 13'' one...flanges need to be welded on anyway, so if it's too short they can just weld some extra piping on

 

hmmm...ill be upgrade to high flow cat soon. Im gonna have 1 end of the pipe expanded so I can slip fit my downpipe to the cat and cat to cat-back with those wrap around clamps from summit.....hopefully it will make taking apart the exhaust a little easier if i want to swap in test pipe for the track or whatever. However until then i still have my greddy evo2 and i don't wanna hack off that triangle flange...what size is that flange and does anyone know where i can find one? (its the triangle flange on the back of the cat.)