I Have a 2001 Honda Civic EX with a DC Catback Exhaust. Recently my catalytic converter seems to have gone bad. The shop i brought it to is telling me its roughly $650 for a new one plus a new gasket and 2 hour labor. There a great shop and i trust them but a cool $1000 isn't really in the budget right now. Especially since i just redid the head and fuel pump about 2 months ago for a cool $2500. I live in michigan so we don't do any emissions testing or inspection for the car.

So im wondering if i remove the cat what am i getting myself into lost of O2 senors? gas mileage? damage of anything? (from what i've read the cat is just there to improve the emissions and maybe make things a bit quieter).

So basically if you have removed your cat what step did you take? Has it gone well? was it a rather cheap operation? Suggestions, input, and advice will be greatly appreciated.

 

ok. replace the cat with a straight pipe. and it will throw a secondary o2 sensor CEL, to avoid this take 2 spark plug non-foulers for ever o2 sensor after the cat on your car. i have a 2000, mine has 1 sensor after the cat. put the non foulers inside of each other after drilling one of them out. then screw your o2 sensor into the non foulers, and screw that into the straight pipe. this should keep a cel light from coming up. do some looking around on google. youll find the article i was reading. im too lazy to do it right now, lol.
i was just reading another article the other day about the benifits of running a cat vs test pipe. test pipes louder, more power, and flows better. as for fuel mileage, prolly wont have much of an affect. might be benificial towards mileage actually. less restrictions n what not. im using a 2.5 inch pipe in place of mine but depending on submodel, i think they started putting the cats on the header in 01??? anyone else know forsure?
as long as its not on the header, itll be cheap, louder, and get a small power bump.
down side is its illegal almost everywhere, youre lucky, and it throws a CEL.
sounds like the benifits outweights the downsides in your case though.

 

The article you're thinking of showed a 1hp difference between a test pipe and an aftermarket high-flow converter. Another difference between a test pipe and any converter is having a test pipe in place of a factory-installed converter is a federal offense and I'm fairly positive it carries prison time; not jail time, federal "don't drop the soap" prison. It's illegal anywhere in the United States, including MI; they just don't do an annual inspection to make sure you still have one.

Also, using any form MIL eliminator is just putting a band-aid on a problem and trying not to think about it; it's quite literally just tricking the PCM into thinking everything's okay.

 

Yeah since they don't inspect i think i'll be fine. Anyways i think the more likely if i do get the police after me for anything related they will issue a loud muffler fine ticket or similar so that there local police/city gets the money.

But once again this is a matter of price more then horsepower. Thanks for your concern tho.

 

what both of you said!

 

I remember when someone stole my cat off my truck straight pipe was the way to go!

 

I replaced the stock manifold that had the converter with an aftermarket headers that deleted the cat. the car runs fine, doesn't stall or anything. The only thing I want to fix is the fact that my air/fuel mixture bounces very rapidly from super rich to the edge of OK and lean. I've been doing weeks of research and cant come up with a conclusion on how to fix this problem. I also don't have the Secondary O2 sensor plugged in. my fuel economy has gone down but only when doing highway driving. If I'm on the back roads my fuel economy seems to be GREAT. Can anyone help me with this problem or any recommendations on how to fix the way its reading?

 

What is telling you that your fuel trims are all over the place and what makes you think you can change them? Do you have a CEL due to the deleted secondary o2 sensor?

 

I have a CEL due to an evap leak (irrelevant) and due to a short in the secondary O2 sensor heater circuit, I figured that would be due to it not being connected. Im going to be trying to use a spark plug non-fouler to see if that evens out the air/fuel problem. Also on the new headers, they misplaced the secondary O2 location so when i try to connect the secondary O2 sensor, it hits the frame of the car and wont let the O2 sensor go in straight ei. I cant thread the sensor in. Also just another add on question, if I were to add a high flow cat to a test pipe after the headers and place the secondary O2 sensor after the high flow cat, would that be a legal substitute for a cat? Not sure if I mentioned this in the previous post, but my car is a 2001 Honda Civic LX with the D17 motor Non-VTECH.

 

Again, what is telling you that your fuel trims are all over the place and what makes you think you can change them?