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how hot should headers get?

Discussion in 'The Garage' started by nsxxtreme, Jan 12, 2012.

  1. nsxxtreme

    nsxxtreme 1/2 ton status

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    Without access to a dyno yet doing a lot of tuning just by what the engine is doing and that ALDL cable sensor readings.

    I have a question on how hot the headers should get. I've got stainless steel headers on my engine. If the timing is screwed they glow red. I always shut it down right away. But I have to pull the timing wire and set the base timing to 0 Degrees. That is enough time for the pipes to turn red hot.

    So I have the base timing set to 0 degrees at idle. With the timing wire plugged in an the ECM in the loop the timing is about 16-18 degrees at idle. In the complete dark which is easier to see when they start to glow red the 2 center pipes start to glow. Its not a bright glow and you can only see it in the complete dark but you can seem them start to turn red. I know some people are able to tune based on exhaust gas temperatures. I'm just wondering if we have any people in here that know what EGT of sbc should be?
     
  2. badmix

    badmix 1/2 ton status

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    Might want to give some specs on the motor, like alot of specs. CID? Compression? Add-ons? Cam Specs? Rocker lift? RPM range?

    A stock 305 wouldnt heat up much but a hi-po race motor will probably be running pretty good heat
     
  3. nsxxtreme

    nsxxtreme 1/2 ton status

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    9.7 compression ratio
    edelbrock etec 200 heads
    edelbrock 7116 manifold
    lunati 60120 roller cam

    So no not stock but not a race motor either.
     
  4. bot0611

    bot0611 1/2 ton status

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    SOmething has to be wrong there... if they get red something is off... my truck use to do that a long time ago when my bro put headders and he left the stock mufflers, i put performance exhaust and done no more red headders... they should get hot enought to burn plastic in time or burn your finger..
     
  5. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    A timing issue is the only time I have ever seen headers turn red.
     
  6. kgblazerfive

    kgblazerfive keymaster Premium Member GMOTM Winner

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    running rich and timing and they will get red but its not the end of the world.
    They can still run when they are red.
     
  7. nsxxtreme

    nsxxtreme 1/2 ton status

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    Timing I agree, this isn't a red you can see in daylight. Only at night in complete darkness. The 2 center pipes glow slightly however the 2 outer pipes do not. It could still be running a little rich because this is still just a base tune.

    I was looking to see if anyone has seen documented Exhaust gas temperature readings that I could use an IR temperature reader and compare against.
     
  8. kgblazerfive

    kgblazerfive keymaster Premium Member GMOTM Winner

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    If you can see it in the day worry at night night big deal other than they should all be the same. Not sure of temp.
     
  9. 1977k5

    1977k5 3/4 ton status Vendor

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    What fuel induction? I bet it's TBI or carb based on the center two cylinders being hotter.
     
  10. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    There are actually 3 things that can cause the headers to glow red hot, could be timing, too rich, too lean. Too lean and that creates heat, too rich and you end up with unburnt fuel igniting in the headers causing the glowing pipes.
     
  11. Richcz28

    Richcz28 1/2 ton status Premium Member GMOTM Winner

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    It's running lean that'll heat up an engine and the headers. Rich cools it down in my experience.

    Do you have an o2 sensor? Get a gauge for it if you do. Or you can monitor it with a voltmeter but I forget the setting to use off the top of my head.
     
  12. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    A rich burn will cool the cylinders but NOT the exhaust system. :deal:
     
  13. nsxxtreme

    nsxxtreme 1/2 ton status

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    New question........

    What cause a motor to stumble? If I go from idle to wide open I'll get a 1-2 second stumble and then it roars to life and starts spinning the tires.
     
  14. nvrenuf

    nvrenuf Bazinga! Premium Member

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    Again, carb or efi? Specifically what kind.

    Both rich or lean can cause a stumble in addition to a bunch of other tuning related issues.
     
  15. nsxxtreme

    nsxxtreme 1/2 ton status

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    54mm big block TBI 60lb injectors running at 22 psi
     
    Last edited: Jan 13, 2012
  16. magik235

    magik235 Still Alive Premium Member

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    The exhaust temperature must reach 600 degrees to activate your O2 sensor. Where is your O2 sensor in your exhaust system. Headers often don't allow the O2 sensor to reach operating temperature. I had to use a heated O2 sensor with my headers before it would work.
     
  17. nsxxtreme

    nsxxtreme 1/2 ton status

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    I have shorty stainless headers so its at the base of the header on the driver side.
     
  18. Safari-K5

    Safari-K5 Registered Member

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    I remember a case kinda like this before. had to do with the MAP sensor with larger cams. the vacuum would pulse rather than stay steady so it would cause the computer to do funny things. i have seen people run fuel filters on them to even out the pulses. if you are not running an O2 sensor like it seems the Map tables will be all over the place while idling causing it to run lean and rich at the same time. If you want my advice get a megasquirt kit and wire that in with what you have now. It will give you the programability and data logging that you really need with a non factory setup.

    check your fuel pressure when getting into the throttle. at times the fuel system can starve for just a second if there is not enough flowthough on your regulator

    600 degrees to activate your O2 sensor... if his pipes are glowing then im sure its quite warm enough to get a reading.
     
  19. nsxxtreme

    nsxxtreme 1/2 ton status

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    Looks like the pipes begin to glow at around 580F. The furthest back pipe on both sides gets hot first. My IR guage maxes out at 600F so I'll need to get a better guage.
     
  20. miniwally

    miniwally 1/2 ton status Premium Member

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    I don't have specific info on egts for this but. On a two stroke snowmobile you don't want to see more than 1200 for very long, I ran mine over 1350 regularly for several seconds and never have melted a piston. However it also depends on the motor package. I had a buddy with a 1100 artic cat that would melt pistons at 1150 degrees guaranteed.

    Diesels take 1200 degrees all the time, I have spiked my duramax to over 1600 several times with no I'll effects to date. Bottom line is the specific motor will set what is safe but I would guess staying near 1000 degrees will be very safe.

    Back in the day when I helped on my grandfathers farm they tuned their irrigation motors on natural gas at night so they could watch how far down the the header the glow went. They shot for a good glow for about 10 inches or so. If you drive through farm country at night every one of those engines glows, they also run at full load for six months a year 24 hours a day.
    glowing headers isn't bad, might not be good either
     

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