Hollowed out Cats

Discussion in 'Performance & Fuel' started by Z71silverado, Nov 23, 2011.

  1. Z71silverado

    Z71silverado Member

    I was thinking of hollowing out my cats. Has anyone done this and did it make a difference? If you did this and it made a difference how did you do it? A friend hollowed out the cats on a Duramax and it made it sould pretty healthy and he claims it made a difference.
  2. BlackJack1500

    BlackJack1500 Rockstar

    Trying to fool the stock engine computer into thinking you still have catalytic converters? You wont be able to do this without a custom tune. How many miles you got on your cats? Are they bad? This could be an expensive mod if you don't have a back set of catalytic converters if something goes wrong. Hopefully if you do this you will have a tune that deletes both of the rear O2 sensors. I once bought a cheap set of headers that came with the off road pipe. Of course the system didn't have cats so that's why it was cheap. I put headers and off road y-pipe on and after 10 mins my truck ran like garbage! Maybe with a good tune I would have noticed a increase in hp and tourque but all I got was an increase in noise. I just couldn't afford a $500 dollar tune at the time. Your truck might be a little better off cause your only deleting the cats and not adding headers but you will certainly have a check engine light on after about 50 miles without a tune. Also is this your daily driver? And how strict are the state emission stations during inspection? If they put the emissions sniffer on your exhaust your will surely not pass. If anything buy a set of headers that come with a y pipe and no cats and keep your stock exhaust around in case something goes wrong. Once you hollow out you stock cats you will not be able to go back and a new set cost about $400 or more depending on the brand.
    Best of Luck to ya.
  3. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Unless you have some major head work, healthy camshaft etc.. you won't see a performance differance over the stock cats. The new cats flow very well as compared to the early cats. Keep them on your truck will run better.
  4. Z71silverado

    Z71silverado Member

    Good to know thanks guys

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