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Cat Removal

Discussion in 'General Tech and Maintenance' started by h22a_in_a_si, Sep 16, 2003.

  1. h22a_in_a_si

    h22a_in_a_si Junior Member

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    I have a 1993 honda prelude si w/ a h22a in it among other things. I have the jdm type S header that has an O2 plug on the 1 pipe section, before the flexpipe and cat. I heard there is a product that screws in where the o2 plug goes and sends the right fuel/air, no matter what the real reading would be with the cat removed. Anyone have more info??? Or possibly another way to bypass the CEL?
    Thanx
     
  2. Tonyd0821

    Tonyd0821 Banned

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    one of the many sites you can get this from....
     
  3. dohcvtec_accord

    dohcvtec_accord WRX Sellout

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    Ummmm....if it's a before-cat O2 sensor, how is it going to throw a code with the cat missing?

    I think you're thinking of an OBD2 engine/car, where removing the cat requires you to fool the post-cat O2 sensor.
     
  4. Tonyd0821

    Tonyd0821 Banned

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    i just did a 2 second search on google for that link.

    there was another product i wanted to show him, but i lost the url...

    all you do is hook up 3 wires to your ecu and it solves the problem of the cel

    due to the o2 sensors being fucked with......
     
  5. h22a_in_a_si

    h22a_in_a_si Junior Member

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    It is OBD I with only the pre cat sensor. But its like 6 inches at most in front of my cat and my muffler shop said it will not read the same because of the temperature decrease with the cat missing, and the different back pressure. Im about ready to rip this damn thing off reguardless! What is the name of the bypass sensor thing so I can look myself. What do you think DOHC Accord?
     
  6. IDMaxGuy

    IDMaxGuy Senior Member

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    of course your muffler shop will say something like that, they are against ILLEGAL things.
     
  7. dohcvtec_accord

    dohcvtec_accord WRX Sellout

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    I don't know. I guess his argument makes sense. I've NEVER heard of that happening before. However, if you trust your muffler shop enough, go with their advice.

    Why not try it out first, and if there's a problem, then try to solve it. If it ain't broke, don't fix it. :)
     
  8. Tonyd0821

    Tonyd0821 Banned

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    i dont remember the name of it. some BIG import/domestic website located in the midwest sells them.

    doesnt matter if your car is obd1 or 2. just mount the device next to your ecu, splice in the wires to wherever the instructions say they go, and

    no more cel.

    simple as that.
     
  9. h22a_in_a_si

    h22a_in_a_si Junior Member

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    Thanks for all of your help, except whoever told me my muffler shop is giving me advice based on legality. If that was their concern, they wouldn't have put my car on a lift to tell me that, they would have given me the whole trillion dollar fine run around. Its my friends shop. importparts.com has a simulator in the electronics dept. I will give it a try in the next week or so and let everyone know the results.
     
  10. h22poweredgsr

    h22poweredgsr Member

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    "The second oxygen sensor is located after the catalytic converter and is used only to detect the performance of the converter. The PCM does NOT use any data from the secondary O2 sensor for engine management." (thats from that link of that o2 simulator.)

    if the ecm doesnt use data from it, then y did my car run rich and was im limp mode wen i had a bad post cat o2 sensor!?!?!??!
     
  11. h22a_in_a_si

    h22a_in_a_si Junior Member

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    OKAY: Even more opinions. My h22a/p72 are both obd I. My speed shop friend said obd I cars don't throw a code when the cat is removed, contrary to what the muffler man said. Again, my car has one O2 sensor on the downpipe before the cat. The speed shop guy drives an accord w/ a h22 in it (all obd I). He said he mobbed with only the header for the first few days after his swap and didn't throw any codes. I am having the cat taken off on Tues morning (9-23-03) with the origional O2 intact. I'll keep everyone posted.
    SJC
     
  12. dohcvtec_accord

    dohcvtec_accord WRX Sellout

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    I think your muffler man has been sucking on one too many mufflers. :D
     
  13. HONDAPITSTOP

    HONDAPITSTOP Senior Member

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    This doesn't answer your question but why not put in a hi-flow cat instead? randomtechnology.com makes some that are 50 state legal and you won't have to mess with fooling the 02 sensor(s) and your emissions will usually be as good if not better than the stock cat all while getting higher flow. I know because I have one in my 90 Accord and did before and after emissions and HP tests. You gain about +2hp with the hi-flow cat and if you just do a straight pipe you may not gain any hp, and may have not enough back pressure issues, etc. Just my 2 cents to try to do a little bit to save the air we breath while still getting better performance our of our cars ;)
     
  14. h22a_in_a_si

    h22a_in_a_si Junior Member

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    Drum roll please........NO CHECK ENGINE LIGHT!!!! Left the primary/sole o2 plug in. Definitly faster than before. Yeah.
     
  15. seanjuan

    seanjuan Senior Member

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    how much did it cost to get a straight pipe made to replace the cat?
    did they just weld a couple flanges onto a section of pipe?
     
  16. h22a_in_a_si

    h22a_in_a_si Junior Member

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    (deep breath)...ok here it goes. I live in Cali (insane smog/exhaust legislation) and drive a 1993 honda prelude si. I did a jdm h22 swap with jdm type s headers, and my "si" tanabe cat-back. The header didn't reach my cat by about 8 inches, so at first I just had a lil extension pipe put in. Then I decided to take my cat off. I hollowed out another Honda cat I got from my mechanic so it still appears that I have a cat. It took me a month to find a muffler shop that wouldn't cry about the laws/fines. You will need a homey hook in reality, thats the only way I found. Anyways, the muffler man cut that little extension piece right down the middle, and unbolted the rear of the cat (the front flanges weren't matching on the hollow cat). Then he bolted up the rear of the hollow one, and welded the front w/out a flange. (the hollow on was like 6 inches longer than my stock cat.
     
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