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burb exhaust

Discussion in '1936-Present Suburban' started by 55Willy, Oct 23, 2006.

  1. 55Willy

    55Willy 3/4 ton status

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    anyone have under body shots of thier exhaust?

    I'm torn between single 3" or dual 3"
    where to put an H pipe how far back to mount the mufflers and where to dump the exhuast.


    and I think I have asked before but do block hugger headers fit the 67-72 engine crossmember?
     
  2. imiceman44

    imiceman44 1 ton status

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    I believe the hugger headers will fit a stock setup (cross member, engine mount towers)
     
  3. 55Willy

    55Willy 3/4 ton status

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    then what I have is a set of block huggers to some 2.5" 90*s to a y pipe with a single 3" flowmaster type muffler to a single tip out the drivers side.
     
  4. dhcomp

    dhcomp 3/4 ton status Premium Member

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    itsn't dual 3" a huge reduction in back pressure on a gas motor?

    I think 2.25 is the reccomended size compromise....but what do i know.
     
  5. 55Willy

    55Willy 3/4 ton status

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    single 3" is stock for a 87 and up.
     
  6. tuffdogstudio

    tuffdogstudio 1/2 ton status

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    Dual 3" with Flowmasters on a 454 with headers, 1986 Engine.
    [​IMG]
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Backpressure is bad, period. The issue is how well the exhaust scavenges, which is affected by diameter, pipe used, etc.

    Backpressure means the engine has to WORK to get rid of exhaust, which is counterproductive. If you can help pull the exhaust out of the cylinder (scavenging) you increase efficiency. Too large exhaust can destroy the scavenging effect just like too small exhaust, but it's less and less important the further down you get in the exhaust stream.
     
  8. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    for a diesel no backpressure is needed, but gas engines need some. i cant remember how much but some is definetly needed.
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Why would an engine need backpressure? Some exists, look at how some measurements of exhaust efficency is measured...pressure. Existence and necessity are two different things. Never is pressure in the exhaust counted as a "good thing".

    Restricting exhaust out means you are restricting air in, no way to make power.

    Spend your time reading these, not listening to me. I guarantee the Vizard article is way more than you ever wanted to know, but I also guarantee you will learn something. Just take the time to read it and leave a learned person. :) Not condescending, he just put a whole lot more into testing and explaining it than I possibly could. I doubt anyone will call him a hack.

    http://www.popularhotrodding.com/enginemasters/articles/hardcore/0505em_exh/

    http://www.uucmotorwerks.com/html_product/sue462/backpressuretorquemyth.htm
     
    Last edited: Oct 31, 2006

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