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Do I really need an EGR valve in the Denver area?

Discussion in 'The Garage' started by dirtynails, Jan 25, 2007.

  1. dirtynails

    dirtynails Registered Member

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    I would be very helpful if I could get rid of my EGR valve. How picky is Colorado Air about this stuff? It's an 83 and it gets put on the dyno.
     
  2. lak2004

    lak2004 1/2 ton status

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    When I went in they didnt look under my hood at all, they only did the dyno test and used a mirror to look at my exhaust. As long as it stays in the limits of the test I would think you should be alright.
     
  3. HarryH3

    HarryH3 1 ton status Author

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    In July and August, you'll be wishing that you had it. It really helps prevent part throttle detonation, which you'll notice the most in hot weather. It also turns OFF at wide open throttle, so it doesn't do anything to adversely affect accelleration. So you don't gain anything by removing it. :(
     
  4. 81 k5 jimmy

    81 k5 jimmy Registered Member

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    I have never ran a engine with one and have never had a problem
     
  5. cbbr

    cbbr 1 ton status GMOTM Winner

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    I don't have an answer, but a question. What is the benefit of not having one?
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Remove EGR on a quadrajet setup for it, and you'll have part throttle cruise issues, whether you notice them or not.
     
  7. 81 k5 jimmy

    81 k5 jimmy Registered Member

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    The benefits are you can run vortec heads and a carb on your sbc
     
  8. dirtynails

    dirtynails Registered Member

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    Well it would go with an Edelbrock 1904 q jet. I don't know if that carb is happy without an egr or not? Anybody out there got experience there? The reason I'm thinking of ditching the EGR is two fold: first, there's is supposed to be a solinoid that bleeds the vacuum going to it. The solinoid stopped working years ago and I have already got rid of the computer that I quess must have controlled the electricity to it. Currently to prevent the EGR from being full on all the time I have installed an in line vacuum delay valve. I didn't think it was slowing it down enough installed in the normal direction so I have reversed it so it's almost like a check valve, but some vacuum still gets to the EGR valve and there is still some decent response in the diaphram from the vacuum--just not as much as it was. So maybe that part is good. The other reason is that the damn valve is actually right up against the valve cover. There is basically no clearance. I would like to get some cast aluminum valve covers so I can solve an oil leak problem and I bet they are just a fraction of and inch taller. so they wouldn't fit. I thought of possibly getting an additional spacer under the EGR valve and that would lift it about 1/4 of an inch. I can't find one. After thinking about all that, it would sure be a lot simpler if I could just get rid of it. That is if both the emmisions turn out good and the carb likes it too. So right now I just don't know the answers. Oh recently there was a thread about valve covers an how crappy the cheap chrome ones are. I can confirm that. I wish I never got them.
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    The ENGINE won't be happy without it.

    Already said twice.

    The carb is calibrated to "assume" that under the right conditions the engine will need less fuel (EGR displaces oxygen, thus less fuel needed) and thus the engine will run lean if EGR isn't present and the mix isn't controlled right at that position.

    Yes, I've got personal experience with this, and at sea level (or very close) a part throttle surge was positively evident until I richened it up via new primary needles.
     
  10. camok5

    camok5 1/2 ton status Premium Member

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    Does it hurt not having one in a tbi engine when its been turned off in the computer?
     
  11. jms

    jms 1/2 ton status Author

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    Vortec heads, sbc, carb, and EGR work just fine.
     
  12. dirtynails

    dirtynails Registered Member

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    I got to say it is fascinatingly complicated. It looks like I keep the EGR and work out the issues with the valve cover in another way. Special thanks to dyeager535, you have helped me before. I am so glad we have this forum.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    IIRC someone (maybe even GM in some applications) made an EGR spacer for valve cover clearance.

    Sounds like your exact problem...I know that many people DO run into that issue with valve covers and EGR.
     
  14. 81 k5 jimmy

    81 k5 jimmy Registered Member

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    I have always driven a pre Egr vehicle until this and 81 never had a problem.
    GM never even put a EGR valve in the 67-72 trucks and they had no problem with part throtle acceleration. The 406 in my 81 accelerates with the best ,passed the emmisions test and will never run with a EGR.
     
  15. longbedder

    longbedder 1/2 ton status Premium Member

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    What dyeager is saying is that it will not run correctly in an engine that is set up to use EGR. 99% of people out there will disable the EGR, because it's smog related and they assume it must be bad in some way. This is probably due to the fact that early (carbed) smog engines lacked power and had a maze of extra equipment/hoses that people didn't understand.

    EGR can actually be a good thing - it reduces peak combustion chamber temperatures when functioning properly.

    Yes, an engine that was never set up to run with EGR can do fine without it.
     

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