Cutting the cats off of my truck?

Discussion in 'GM Powertrain' started by ras, Feb 2, 2009.

  1. ras

    ras Rockstar

    I am considering cutting the cats off my truck and I was wandering if that would mess with my O2 sensor since its after the cat.
  2. dbltap

    dbltap New Member

    Big mistake, and one you will soon wish you hadn't made.The bottom line is the truck will not run correctly without the cats or an o2 censer designed to make the computer think that they are there. With that expense in mind better off going with high flow cats. My 02.
  3. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Their there for a reason.
    The way engines and computers are designed these days the truck wont run very well. Not to mention the check engine light your gonna get unless you use an O2 sensor tester on the O2 sensor.
  4. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    get high flow cats, you can find magnaflow cats on ebay for very cheap
  5. eli98

    eli98 New Member

    I understand your desire to increase flow for cheap, but unless you are willing to spend a few hundred dollars to add sensor bypass units, and have your ECM remapped, you're not really going to accomplish anything other than pollute more. You can add power by removing them, but it's expensive, and should only be a thought as a last resort to squeeze out a few extra ponies for the track or off road purposes. High flow cats are your best bet, with a decent cat back system to follow. You will get great sound, better performance, and best of all, tolerable emissions. Also my .02 cents
  6. ras

    ras Rockstar

    Well I'm not trying to get more power it just seems like the truck aint breathing right anymore and its gettin up there in miles. They have to be on there way out.
  7. mjalstad

    mjalstad Rockstar 100 Posts

    Contrary to what a lot of people think, it will not wreck the way your truck runs at all due to the O2 sensors. The ones before the cat are the only ones that affect engine calculations, the ones after the cat are only there to monitor cat efficiency. If you have a diablosport predator tuner, you can delete the O2 code from your PCM so the check engine light will not come on. If you think your truck isn't running right because of the cats, drill a hole in the exhaust pipe just before the cats and see if it runs better. If it does, then remove or replace them. If it still runs the same, have your drilled holes welded up and save the money you would have spent on replacing cats. If you remove them you will pollute more and you will probably not have as much backpressure in your exhaust so you could lose power that way, or so I've heard. I have a 98 regal that had a really leaky exhaust right after the cat, it would have been hard to replace the pipe after the cat while saving it, so I just hacked the cat off too. I didn't notice any loss in power or gas mileage.
  8. dlewis1111

    dlewis1111 New Member

    Don't forget the 10,000 (each) fine from the EPA for getting caught removing them. I wonder if the moderator knows that the possibility of committing a felony is being discussed here.....
  9. 05azsilver

    05azsilver Rockstar 100 Posts

    Unless you had a diesel, I would recommend against it. If you really want to you can get some high flow cats like mentioned above, but I would highly recommend cutting them off.
  10. werty

    werty Rockstar 100 Posts

    punch them out and put em back on....but you didnt hear it from me....:neutral:

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