nevertoold

Can some explain quickly (I did do a search - but couldn't find a clear answer).

I would like to better my exhaust system. My question is around the elimination of the cats. I know it isn't legal for the street because of emissions( but who will know if know one checks - I live in one of those states where I am exempt for the first 3 years and after that they just query the module(what a joke).) If I remove the cats are there 4 sensors 2 up and 2 down? If there are no downstreams(or cat monitors) I shouldn't have any problem with Check engine lights. Is this assumption correct?

What I would like to do is run a full JBA system. Long tube headers and OR h-pipe etc.


07 Redfire GT 5spd
C&L cai SCT with 93 tune

Hufenstang

get all that and you will need a tune, and with the tuner you can just adjust it so it doesnt check those sensors so the light never comes on for it!

nevertoold

I have Brenspeed tune they would take care of that. But are you saying there are downsteram sensors?

Hufenstang

i honestly dont know about the sensors, but i am using the full jba l/ts and o/r h pipe and i have no check engine light

modular81

Yes there are four 02 sensors, two upstream and two downstream. The upstream 02's monitor your a/f in closed loop(part throttle)and the two downstream 02's monitor your cats to make sure they are working properly. When running longtube headers and o/r midpipe, tuners will simply turn the downstream 02's off in the tune and adjust a/f so you want run lean at open loop(wide open throttle). The fronts have to be on at all times and the rears don't.