Thinking about new exhaust

Discussion in 'New Members Section' started by AMS3, Nov 7, 2019.

  1. AMS3

    AMS3 Member

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    I'm thinking about replacing the stock manifolds with Kooks long tube headers and 3" stainless exhaust with no Cats or Resonators. Will this hinder the hp of my engine, or give it more hp?
     
  2. CaptnCrash

    CaptnCrash Full Access Member

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    You will get a boost. BUT it will take a tune and some post-cat O2 sensor simms or a tweak in the tune to eliminate them.
     
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  3. AMS3

    AMS3 Member

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    Not sure what you mean by "post cat shims". What tuner do you recommend? I'll be having a Speed Shop do the work, as my knowledge of welding and tuning is about the size of a pea.
     
  4. CaptnCrash

    CaptnCrash Full Access Member

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    That would be post-cat O2 [ after the cats, downstream, etc ] sensor SIMMS [ no H ] ... If you remove the cats you either have to fool the PCM about the presence of the 2 post-cat or downstream O2 sensors and the results they provide about the condition of the cats, or get a tune that causes to PCM to not have a problem with them being missing.
     
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  5. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    I don't know if Kooks provide gaskets with their long-tubes, but I'd use the o.e.m. exhaust manifold gaskets for best results.

    Why do you want to run without cats anyway?
     
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  6. AMS3

    AMS3 Member

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    I don't have to worry about DMV emissions testing where I live ( GA ) and want as much unrestricted flow as possible.
     
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  7. AMS3

    AMS3 Member

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    Ahh yes, now I know what you're talking about. My last truck was an 05 QC Ram 1500 with the Hemi. I had Kooks headers and one of the O2 sensors was removed because I deleted the Cats. Engine light stayed on, but I didn't notice anything as far as loss of power, etc. The speed shop wanted $300 to make the light go out. I said no, I can live with it on.
     
  8. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    I'm just asking because these engines really stink without cats. I've known guys to put them back on because of it.

    I've got (4) decent high-flow cats on mine and I don't care about the small horsepower loss (if any). I shift it at over 6500 and there is no indication of restriction.

    Have fun.
     
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  9. CaptnCrash

    CaptnCrash Full Access Member

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    I've been running without cats for 15 years now. I don't know "stink". Actually it's cats that smell like rotten eggs.

    At any rate, 4 cats = tons of heat, and really hot like melt stuff heat. They also = restriction and hp loss. I prefer to not set the woods on fire and get better mpg's.
     
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  10. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    Aughh.. If your cats smell like rotten eggs (after warmup) and are really hot, there is something quite wrong.

    As for power loss, with high-flows in your exhaust system, it's quite small.

    BIG difference between now and the early 1970s when cats failed, stunk like rotten eggs, operated at really high temperatures and were super-restrictive.

    Anyway, enjoy the headers, they should help.
     
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  11. GSJake

    GSJake Member

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    Dont do a straight exhaust, use some type of muffler. I have a Borla with the mufflers deleted (4 factory cats in place) on when I bought the truck a little over a year ago. Its loud which at first I liked.. then you drive it and it wears on you. I have an appointment on Tuesday for my exhaust guy to put a dual chamber "flowmaster" style muffler in place.
     
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  12. AMS3

    AMS3 Member

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    Thanks for the advise guys, I'll take it under consideration.
     
  13. beastmode1

    beastmode1 Full Access Member

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    Mine is stock less the last resonator at the back tail pipes. I removed it and it is pretty loud when you step on it. I get a lot of questions if i did anything to it.
     
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