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What diameter exhaust?

Discussion in 'HYBRID -> ED-EF / DA' started by wagovanb16man, Nov 5, 2007.

  1. wagovanb16man

    wagovanb16man i

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    Alright, I'm sure this has been covered a lot, but I don't have time to go searching, I'm getting some new piping ran today but I don't know what size to use..

    Skunk2 said to run 60mm which converts to 2.36 inches, and I'm not sure whether 2.25" would be sufficient.

    My mods are:
    -JDM B16a
    -Skunk2 Intake Manifold
    -Thermal Intake Gasket
    -MP2 Lightweight/Underive pulley (Only 1.14 pounds!!)
    -Cold Air Intake w/ custom ram air
    -Aerospeed FPR w/ Gauge @ 56PSI

    I plan on getting a skunk2 throttle body, and might step up to some cams later on down the road. What size exhaust do you recommend, and would 2.5" be too much?

    This is on a 1990 Wagovan, btw..
     
  2. 99sidude

    99sidude Moderator Moderator VIP

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    I have a skunk2 2.5" exhaust on my car. When it was N/A and close to stock, it worked just fine.
     
  3. formby

    formby learning in progress

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  4. wagovanb16man

    wagovanb16man i

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    Even though 2.5" is .14" bigger, and 2.25" .11 smaller? Wouldn't it be better to run 2.5" so that I have enough room for future modding?
     
  5. Cashizslick

    Cashizslick !i!i!i!i!i!i!i!i!i!i!i!

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    No.


    2.5 will be less efficient and will create backpressure.

    The 2 & 1/2 will yield the best flow for your NA 1.6L. If you were to go with a forced induction setup, then (and only then) would it be worth upgrading to a 3inch exhaust.
     
  6. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    Dude, check your numbers lol It doesn't make sense but I think I know what your trying to say :lol: oh, and don't you mean 2.5 will have less back pressure? You been drinking cash? lol

    IMO, I say it depends on if your exhaust will have all manderel(sp?) bends or will it be crush bent. If you are gonna have manderel bends then 2.25 will be good. If you will have a custom crush bent exhaust then the bends will be 'pinched' and will make the diameter a little smaller. So if this is the case, i'd go with the 2.5 for crush bent.
     
  7. norcalgsr

    norcalgsr Honda Master Technician

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    If you're planning on replacing the cams, which I would recommend to take advantage of the intake manifold you installed, I would go 2.5" now so you don't have to upgrade it again in the future. It may or may not be a little too large for the time being, but if you're planning to do more upgrades down the road you'll be glad you went bigger now instead of replacing it later.
     
  8. Cashizslick

    Cashizslick !i!i!i!i!i!i!i!i!i!i!i!

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    Mandrel bent 2.25 for the win.

    You need an exhaust that is properly sized for your application. All the R&D/testing that has been done in the industry has revealed that 2.25 is the best diameter for a stock-ish honda motor.

    Going bigger will reduce your power on an n/a honda motor . . be it back pressure or different flow characteristics, it has been proven.
     
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