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Back Pressure............

Discussion in 'Engine Building' started by RoadRage, Oct 15, 2002.

  1. RoadRage

    RoadRage Member

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    Is it good to have a little back pressure in the exhust system of a NA engine. I know with turbo you don't want back pressure so the turbo can spool faster, but what about NA. Pro's and Con's anyone? ;)
     
  2. lsvtec

    lsvtec GNU/Linux Evangelist

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    Back pressure = bad. The back pressure myth is BS. It is all about exit velocity. You want the exhaust gasses to exit the cylinder as fast as possible to create a vaccuum.
     
  3. pissedoffsol

    pissedoffsol RETIRED

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    IMO, 0 is bad. a little is good- stock, sucks.
     
  4. chet

    chet Senior Member

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    i wouldn't go so far as to say its a "myth." yes, a more freeflowing header and exhaust is great, but why doesn't every aftermarket exhaust come in 3 inch trim diameter. its because too much flow can change the combustion cycle by creating too much flow. this will lead to reduced power in lower rpm's.

    as is the case with most applications, a compromise is best. stock exhausts are designed for the consumer wanting a quiet, yet efficient design that serves its purpose well.
     
  5. knowledge

    knowledge Senior Member

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    I believe you need a little backpressure for the valves. They will float like hell with zero backpressure.
     
  6. lsvtec

    lsvtec GNU/Linux Evangelist

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    Why would they float at 0 back pressure? That doesn't make any physical sense. Technically 0 back pressure is not possible, there will always be some resistance to the flow or gases out of your engine.
     
  7. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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    :werd: unless you were running your car in a vaccum there would be some kind of resistance just from the ambient air pressure



    and speaking of "back pressure"... damn B 2 years!!! thats gotta suck
     
  8. lsvtec

    lsvtec GNU/Linux Evangelist

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    That's what I said.
     
  9. pissedoffsol

    pissedoffsol RETIRED

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    i wouldn't know what sucking is like anymore either

    lol
     
  10. lsvtec

    lsvtec GNU/Linux Evangelist

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    We need to start a get Brian laid fund.
     
  11. knowledge

    knowledge Senior Member

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    lmao! Dont go to Reno to get a hooker! I tried this past weekend for my brother inlaw and it was $500. Better off renting a video B.
     
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