I have an off road x-pipe on mine lol. Lucky for me the state of ohio doesnt give a hoot about the enviornment. Its probably those cats tho because a buddy of mine had the same pipe on his 08 went through a random check point and failed.

 

Do you know if the stock cats & h-pipe will bolt on to the Kooks l/t headers? i finally found a stock h-pipe & cats but wonder if im going to have to go to a muffler shop & have them cut the system up! i hope not,paid way too much to cut that Kooks system up!! Thanks for all the help.

 

i don't know if it will or not, hopefully someone who has done it
will weigh in.

 

I would bet you are right. Even a properly running engine will still emit about 1-2% CO and maybe 150-200 PPM of HC. The cat coverter is supposed to alter the NOx gasses and burn off moderate amounts of HC and CO.

The front O2 sensors are used to regulate the air / fuel mixture, the rear O2 sensors only vefify that the cat converter is cleaning up the exhaust. I doubt anyone turned the rear sensors off, that would be considered tampering an emission conrtol device. The EPA would be all over that.

 

With no cats, you can smell unburnt fuel in the air. With cats, no smell. The hi-flows just don't burn enough of the fuel and are known for failing. I would cut them out and weld your stock cats back in.

They are street legal, and meet all the requirements, but they don't work well enough in some cars to pass.

 

The stock H-pipe won't bolt up because they are made for a shorty header or the stock manifold you would have to modify it or just get a shorty x-pipe and reuse the cats or get slphigh flow cats

 

Just lean it out for the test. I'm pretty sure my sct tuner had an option to add or remove fuel in different rpm ranges.

 

Just want to say thanks to everyone for all the help! I finally passed emissions! I simply returned the car to the stock & passed no problem! Thanks again for all the help.

 

nice! glad it worked out well.

 

Congrats, now go back to fun tune! LOL