i posted this in the prelude section but didn't really get a sure answer so i'm moving it here:

do any of you guys think that having a 3" custom pipe catback on an jdm h22 a bad idea? Do u think its better to get 2.5" because of the ground clearence and the fact that i think i'm losing some torque. I'm not boosting! but just tuning my h22 with a safc
what do u think? Will effect my performance if i go 3" rather than 2.5"

 

I had a h22a bone stock tuned with VAFC. I got good numbers with 2.25 piping.. I would think 2.5 would be good for a modded H22a. But 3" is out of the question unless its fully built.

I got 170whp and 151tq.

 

its only suposed to be2.50 inches(for nitrous,turbo,supercharger add atleast .5 inches to diameter. source high- performance honda builder's handbook vol.1

 

Dude, you had some of the most knowledgable Prelude owners in the forum to answer your question, and you say you didn't get a "sure" answer?!

As was said in the Prelude thread, 3" for an n/a car is a bad idea. Listen to good advice when it's given.