98 5.7L Headers - Possibly stupid questions

Discussion in 'Exhaust' started by red98, Apr 2, 2021.

  1. red98

    red98 I'm Awesome

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    My truck is a 1998 K1500 5.7L, currently has stock exhaust down to the rear cats. I had to chop off the mufflers the other day because one of them blew in half, and they were both rattling. When I dropped the tailpipes to the floor a bunch of the catalyst material fell out of the mufflers, so I'm assuming my cats are shot. No emissions testing in my area, so I don't actually need them, I don't care if I keep them or not, but I don't want my truck to bog down in "limp mode" or whatever if I do get rid of them.

    So my question (maybe questions) is, if I get longtube headers would it delete the front and/or rear cats? Would that cause "limp mode" or anything similar? Assuming the o2 sensors are plugged into the pipe somewhere. Also, do I need both sets of o2 sensors? I know the front set is crucial, but what can/should be done with the rear set? Do shorties remove the front cat? Could I run shorties and not touch the stock exhaust other than the manifold? Would my engine know the difference between current stock setup, and longtubes with no cats, but with the o2 sensors plugged into the pipe?

    I'm almost entirely undecided on what to do, other than the fact that I want headers, I'm open to keeping or deleting one or both sets of cats depending on what the effect would be, and what the cost would be. I just don't know a whole lot about headers/exhaust.

    Thanks for your time, I know a lot of this is probably answered elsewhere but I've been looking for a while and can't find anything concrete.

    PS: Cheaper is better (but I don't like to replace shit twice, so I'll prob go Stainless for the pipes), I'm less than $2k into this truck, including EVERYTHING, I'd like to keep that $ amount pretty low lol.
     
  2. b454rat

    b454rat I'm Awesome

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    Mine ran better without cats. But I had some rather unique fixes on mine. I put spark plug non fowlers in each side, no check engine light.
     
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  3. L31MaxExpress

    L31MaxExpress I'm Awesome

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    Needs to be tuned regardless of what you do for headers.
     
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  4. GoToGuy

    GoToGuy OBS Enthusiast

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    My 98 tahoe short ceramic coated headers( my model no air injection tubes/ smog) . Ceramic headers contain heat to carry out through exhaust rather radiate into engine compartment. Not alot but it noticeable. 1st pair of exhaust gas sensors are for engine power, mixture soforth. Second pair after cats are monitoring catalytic converter health. The problem with changing the process is providing false signals to ecm. Or changing parameters within ecm to ignore aftercat monitoring. Gotta have a way for the ecm to regulate the fuel required and monitored result. Good luck.
     
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