im wanna run catless but i need a cat to pass emissions but does anyone know how to trick out the o2 sensor so when i get it emissioned it will pass with no cat i know the sti and wrx owner do it. any help please?

 

There's no oxygen sensor to "trick" on a 91 firebird.

That vehicle doesn't monitor the converter

First you have to understand how a oxygen sensor works before I could explain how the system works on newer catalyst monitoring vehicles.

If your state performs the running test they'll catch it that you have no converter

 

milford,ct huh i am in groton!! but anyway i dont know how the ct inspection goes but if its just visual, just take your cats out and hollow them out and put them back so it looks like you got them in!! and your o2 sensor aint got nothing to do with your cats, your o2 sensor is around your exhaust manifold but also plays in with emissions.

 

ok cool man thanks ill do that tomorrow and hollow out the cat for the hell of it thanks for the replys . also how does the o2 sensor play a part with emissions

 

The upstream O2 sensor (the one in the manifold) plays a part in emissions controls, in that it plays a major part in the ECM's constant recalibrating of the engine controls - its what lets the ECM know whats going on as far as fuel goes... too much, too little, just right, etc. A constantly self-adjusting system like this can't be done without an O2 sensor in the exhaust system. With the self-tuning ability, comes better performance, economy, run quality, and emissions control.

 

also make sure with the long tube headers you get heated O2 sensors! also are there any drags in this freakin state man?
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with the post above i was assuming you have long tube headers? if you dont then ignore the heated o2 sensors, but if you do have long tube headers you might have and issue with having cats, b/c there is going to be a whole lot of room from the headers and y-pipe to the big pipe running down the center

 

theres no drag i know of but im gonna be heading down to the one in Lebanon Ny when it opens.

 

how far is that from groton?

 

its kinda far man but when it opens again we could hook up if you want to go i havent been there at all but theres a first thing for everything we can take RTE7 where i live and take it all the way up to US RTE 20 it could be like a weekend thing im sure alot more people would go also leave like on a friday come back sunday afternoon

 

No, do not hollow out the cat for the hell of it. A catalytic converter is required by federal law, as it really helps to clean up the air. The stock ones are restrictive but the aftermarket ones from Magnaflow, Catco, or Random Tech are not. Please do your part to be a responsible hot rodder and keep the cat on your car.

 

iam now keeping the cat on and im not gutting it neither i decided to go a different way with my exhaust.

 

Even if you gut it out and replace it, most smog tech will tap it, and if it is hollow. It sounds hollow = Fail, and Fine.

 

You won't pass the sniffer test without a cat, even if you do pass the visual. Its just too important of a component to leave off of something thats going to get sniffed. Its won't pass. If it could pass without it, GM would never have put it on in the first place. Its not illegal to remove it because the government said it has to be there, its illegal because GM put it there, so it has to stay there. If GM could have made it pass without adding that $500 component to the car, they gladly would have.

Just get a good aftermarket cat and use it... you won't lose any power through it, it will pass the sniffer (or at least get you that much closer), and you won't be one of "those guys" that gives hot rodders a bad rap for being careless poluters. I'm no eco-**** by any stretch, but I think its just stupid to remove an emitions component just for the sake of removing it. My '97 LT1 still has all the emitions components - AIR, EGR, both cats, both rear O2s, etc - and all are still functional. When I get a set of headers for it, I will be getting a set of '50-state' headers and keep all those parts functional. They aren't hurting anything performance wise, and its not a bad thing to try to keep the air a little cleaner.