I have a 2000 Integra w/ B20B. Engines running poorly and CEL is on do to the cat. For daily street driving, is it better to replace it with a high flow cat or test pipe as we don't have emissions inspections here in Oklahoma? My concern with a test pipe is I don't want to make myself or my daughter sick from exhaust fumes as we have sensory disorder.

 

Are you already swapped to OBD1? My 2001 GSR is using a P72 OBD1. I believe your going to want to OBD1 swap and run a P75 ECU if not all ready, unless your running a different ECU that's chipped. I'd also run an adjustable fuel pressure regular if it was me so it it runs a little lean because the P75 is for a 1.8l, not a 2.0. I have a test pipe on my car and have for years. It does make the car louder. It wouldn't be bad with a stock exhaust but it's pretty loud with my 2.5" exhaust. You can smell it at stops sometimes. Not sure how much this would bug you. Drive throughs I definitely smell it but my car runs rich due to an exhaust leak from a broken exhaust manifold bolt. A cat in my opinion is like a clogged air filter. They kill a little power and fuel mileage. I'd run a resonator over a straight test pipe. Unfortunately like a lot of parts I've bought. My specific resonator said specialty for a GSR and it wasn't. It was 16.5" which I believe was for an ITR and my cat was 17.5/8" I had to cut and extend it. When I contacted the seller, like a few times before with parts. The guy said "all B series parts are the same" and it was a direct fit, when in reality it wasn't, so measure before you buy one. I'm not sure how the car would have ran on stock OBD2B ECU or if a defouler would have worked. I've only ran it like this on OBD1.

 

My car is OBD2. In the case of a test pipe, I'm finding a version labeled as a "resonated test pipe". As to improved cats, I've used a direct fit Random Technologies high flow cat that as certainly better than stock. Since I've never used any form of test pipe before do to having lived in states with anual safety and emissions testing, they are new to me. The guy that claimed all B series are the same is an idiot.