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Thread: EGT probe and flow restriction

  1. #1
    Supporting Member Turbo Mopar Contributor
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    EGT probe and flow restriction

    My CSX has a EGT stuck into exhaust at #4 but I am concerned with the size of the probe considering the size of the port.
    I am considering removing it as I have a good A/F installed but thought I would ask before I yank it out. I also recall discussion on the incredible amount of time it takes the thermocouple takes to reach the actual correct reading.
    What are your thoughts?
    Last edited by chromguy; 06-03-2021 at 10:22 PM.
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  2. #2
    Hybrid booster
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    Re: EGT probe and flow restriction

    I never thought about the restriction caused by the probe as it is more than offset by the benefit of higher boost which the EGT gauge supports.

    I can see how a wideband gives a better picture of the mixture, and have one now too, but I still run the EGT.

    5Digits believed the proper location of the probe was in the turbine inlet.

    http://www.turbo-mopar.com/forums/sh...ighlight=probe

    I recall there being a thread where he was surprised people have been putting them in the #4 runner, but I couldn't find it.

  3. #3
    turbo addict
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    Re: EGT probe and flow restriction

    Having flowed several stock and ported log exhaust manifolds, #3 & 4 will always show hottest (leanest) on EGT. #2 being the worst flow will be the fatter of all of them. Being in the turbine inlet or downpipe, is going to be an average of the 4 cylinders, just like a wideband. So one just needs to pick their poison.
    Todd

  4. #4
    Supporting Member Turbo Mopar Contributor
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    Re: EGT probe and flow restriction

    Quote Originally Posted by Oggie Fisher View Post
    5Digits believed the proper location of the probe was in the turbine inlet.

    http://www.turbo-mopar.com/forums/sh...ighlight=probe

    I recall there being a thread where he was surprised people have been putting them in the #4 runner, but I couldn't find it.
    I remember this one

    - - - Updated - - -

    Quote Originally Posted by 4 l-bodies View Post
    Having flowed several stock and ported log exhaust manifolds, #3 & 4 will always show hottest (leanest) on EGT. #2 being the worst flow will be the fatter of all of them. Being in the turbine inlet or downpipe, is going to be an average of the 4 cylinders, just like a wideband. So one just needs to pick their poison.
    Todd
    Todd, sounds like you are not concerned with any flow restriction caused by the EGT in #4
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  5. #5
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: EGT probe and flow restriction

    There are thermocouples which are significantly thinner than what one gets in an Autometer type kit from back when. They react much more quickly, but they don't last as long. I too wouldn't worry about the flow in #4 especially. I think I had mine in #3 back when and it was just fine.

    In regard to the value of them in tuning, it is ideal to have one in addition to the AFR gauge, as the EGT tells you when you're octane limited.

  6. #6
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    Re: EGT probe and flow restriction

    Quote Originally Posted by chromguy View Post
    I remember this one

    - - - Updated - - -


    Todd, sounds like you are not concerned with any flow restriction caused by the EGT in #4
    Hey Miles,
    Keeping in mind that #4 outflows the other ports, one could say that it would hurt the least, or that it could even help balance out the flow of the manifold. Yes you are correct, I would not be concerned about a probe in #4 port hurting flow. Whether you really need a EGT for your vehicle is another question. Typically it is for guys wanting to push the envelope (calibration and boost wise). It could be a valuable tool if you start getting into custom calibrations. That being said, I always have some reservations about anything that could be ingested into the turbo. That is the risk you take.
    I've had Westach EGT sensors last for well over a decade in some of my summer drivers.
    Todd
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  7. #7
    Supporting Member Turbo Mopar Contributor
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    Re: EGT probe and flow restriction

    Quote Originally Posted by cordes View Post
    In regard to the value of them in tuning, it is ideal to have one in addition to the AFR gauge, as the EGT tells you when you're octane limited.
    Oh I did not know, do you have a link to a reference so I can read up a bit more?
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  8. #8
    Supporting Member Turbo Mopar Contributor
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    Re: EGT probe and flow restriction

    Quote Originally Posted by 4 l-bodies View Post
    if you start getting into custom calibrations. Todd
    Yes that is where I am going. So I am starting to see the value of both so I will leave the EGT for now
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  9. #9
    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: EGT probe and flow restriction

    I like having an EGT gauge with a g head on a 2.5. getting the timing in the sweet spot where you dont have knock and dont have high EGTs is a little tricky.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

  10. #10
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: EGT probe and flow restriction

    Quote Originally Posted by chromguy View Post
    Oh I did not know, do you have a link to a reference so I can read up a bit more?
    Just late night conversations with 5 digits. As you retard your timing, EGT goes up. You can have a nice AFR, but when the EGT gets dangerously high, that's when it's time for higher octane. I had an EGT and AFR in my old Omni and it was very interesting, while being very helpful in dialing everything in. Even at cruise and idle, it was nice. That was the best running car I've ever owned drivability wise.

  11. #11
    Supporting Member Turbo Mopar Contributor
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    Re: EGT probe and flow restriction

    Thanks everyone, I will leave it installed
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

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