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Wondering whether the the 2nd O2 sensor comes before the catalytic converter. I'm thinking of getting a custom exhaust done and replacing the cat with a test pipe or high flow resonator (before you get on my case theres an article over at probetalk that says the cat contributes to global warming). Will taking off the cat cause my engine to run badly because the ECU is getting messed up readings? Thanks.
 

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Both O2 sensors are before the cat on the 93-95 model, one for each exhaust manifold. It's only the 96-97 that have a O2 sensor after the cat, for OBD-II. So you should be fine mechanically. Just be prepared for a very loud exhaust. most of teh guys who have done test pipes say that the exhaust became much louder, and if you are having a free flowing exhaust built at the same time it will add to it.
 
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Discussion Starter #3
A high flow resonator should cut down on the noise though right?
 

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Greg is right. There are two O2 sensors on the 93-95 cars, one each for the left & right cylinder banks. They are located in the down-pipes for each bank. Removing the cat should not affect the O2 sensors.

And while it's true that the cat produces CO2 (carbon dioxide) as one product of the catalytic reaction, the benefit of the reduction of carbon monoxide, oxides of nitrogen and unburnt hydrocarbons (NOx to nitrogen gas and CO and hydrocarbons to water and CO2) far outweighs the risk of the added "greenhouse" gas CO2.

A healthy catalytic converter does not pose a significant flow restriction to the exhaust gas. "Healthy" meaning that it's not clogged with deposits from running too rich or oil burning and that it hasn't been damaged by overheating etc. I've not heard of any compelling testing that's shown removal of a healthy cat will produce noticeable power gains. Not on this car (small displacement, low specific output) anyway.

More and more jurisdictions are instituting emissions and inspection programs. Yours may not, but you might want to check if it's in the pipeline before removing the cat.

And as Greg said, the noise will go up significantly. It will sound much less "refined" and much more raspy. It may not be something you'll want to live with. If you do remove the cat, make sure you can re-install it if you don't like the sound.
 

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2nd O2 sensor

its gonna be before the cat... look up under your manifold... ur gonna actually have to crawl up under ur car and look... youll see it right in that open space...
 

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Umm... No Post in almost 3.5 years but none the less your right.
 

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lol..crap man. First you post about a new site called CarDomain and then reply to a post that's 4 years old? Are you living in the past?! Timetravel.
 

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I saw Mike94PGT, and I seriously thought Mike came back. Kinda dissapointing now. There should be some sort of ban on resurrecting old posts. My spirits are down now. :(
 
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