I have a question. I just put on a new cat back and it's alot louder than I thought. My CEL / ATTS lights are on and the ECU is throwing a P0420 code: Catalyst efficiency below threshold.

If the ceramics inside my cat are broken would this cause my 5zigen exhaust to be louder than normal? Also, when i turn off the engine, I can hear loud pops and crackles coming from the converter. I'm assuming I need a new one. Will this one be okay w OBDII? http://www.mufflertech.com/htm...id=58

I've heard that high flow cats don't work well w/ OBDII. I just don't want to get a new cat and have the CEL come on again.

 

get a high flow cat and a O2 sim

 

Gotta pass GA smog test though. And I would rather my CEL be fully functional in case something really goes wrong.

 

im assuming you have the original cat on there from the factory. if somethings is broke with it and your car has less than 80k miles on it Honda will replace it for free. I dont know what their policy is on aftermarket exhaust components though. Of course this will just leave you with an OEM cat. stock diameter. But, it will be the most reliable cat you'll find.

 

o2 sim wont make your CEL not work. it'll just make the cat problem thing go away. and with a high flow cat you'll still pass emissions.

 

So how's the O2 sim work and how much? And what about the cat in my first post. Is it okay to get that one?

 

theres tons of threads on the O2 sim, just search. that cat should be fine.

 

Thanks for the info. 'preciate it!