AMS3
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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?
Thinking about new exhaust
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CaptnCrash
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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.
AMS3
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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.
CaptnCrash
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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.
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?
Why do you want to run without cats anyway?
AMS3
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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.
AMS3
Well-Known Member
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.
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.
CaptnCrash
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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.
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.
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.
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.
GSJake
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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.
AMS3
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Thanks for the advise guys, I'll take it under consideration.
beastmode1
Full Access Member
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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