Really...does a u-turn in an exhaust pipe cause resistance in air flow?

Discussion in 'Technical' started by scooper77515, Mar 28, 2011.

  1. scooper77515

    scooper77515 No current projects.

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    Seems counter-intuitive.

    As long as the diameter of the pipe stays the same, it seems like I should be able to do a u-turn or two in my exhaust pipe without restricting flow in any way.

    Can anyone provide "science theory" that shows that a u-turn would hurt my exhaust flow?
     
  2. Bryant

    Bryant forgot more than learned

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    every turn or bend is a restriction. its not that simple. you also have to consider the pipe diameter and requirements for your motor. a 302 with 2.5 exhast with mandrel bends should not see any significat power loss from the bends. i would expect the power to improve due to the increase in back pressure. a near stock 302 should run beter with 2.25 exhast.
     
  3. scooper77515

    scooper77515 No current projects.

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    that is what I figured. Unless you were stressing out the exhaust system by pumping near-capacity exhaust through it, I didn't think a mandrel bend would make a difference.
     
  4. 71gold

    71gold Frank Cooper Supporting Member

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    :hmmm:...what makes this..."science theory"...:huh:
    sounds more like..."science opinion"...:yup:
     
  5. bmcdaniel

    bmcdaniel Senile Member

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    Well, if you think about it, no fluid likes to bang into walls (deflection) or change directions (inertia)It would rather just see the open end of a straight pipe.
     
  6. rthomas771

    rthomas771 Member

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    Last edited: Mar 28, 2011
  7. Bubba Bob

    Bubba Bob Member

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    I don't know exhaust... but from a purely physics stand point... ANY change in direction equals acceleration. So no, you can NOT have a U-turn in the pipe with out restricting in 'any way'. It will cause a small restriction, no matter how minimal. :huh:
     
  8. scooper77515

    scooper77515 No current projects.

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    Good point, and science THEORY!!!
     
  9. cactusgrabber

    cactusgrabber Member

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    This isn't an actual "Science Theory" based on a benchmarked study...but this thread from another forum talks about a very similar question....and goes into pretty good detail.

    The general concensus is: DOES NOT RESTRICT FLOW. As long as you don't kink the pipe or change diameter, then the effect is minimal.

    http://forum.miata.net/vb/archive/index.php/t-242679.html
     
    Last edited: Mar 28, 2011
  10. Blown74

    Blown74 Member

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    exhaust

    And don't forget that exhaust is a series of pulses of both sound and gasses, and any and all bends would adversly affect flow to one degree or another. Maybe not enough to notice , but a change nonetheless.
     
  11. scooper77515

    scooper77515 No current projects.

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    I notice that when I take my 100' water hose, and put a bunch of turns in it, it doesn't seem to affect my sprinkler all that much (if any)...

    Of course, I am running a John Deere on it. Might make a difference.

    [​IMG]
     
  12. Bryant

    Bryant forgot more than learned

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    if you want science dont goto a maverick fourm. if you want smart a$$ responces step right up!!!
     
  13. scooper77515

    scooper77515 No current projects.

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    I think I DID step right up!!! :bananaman
     
  14. PaulS

    PaulS Member extrordiare

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    The exhaust is a compressible fluid with a sound pulse traveling back and forth through the pulse. A change in size of the pipe or direction will make signifigant changes in the inertia and scabanging effect it has on the engine.
    Will it cause a signifigant restriction to gas flow? no, not a signifigant restriction but it will alter the effect at the engine in a big way because it changes the sound pulse direction and intensity.
     
  15. bmcdaniel

    bmcdaniel Senile Member

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