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  1. #1

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    water exhaust mod

    i remember reading somewere about routing the water from the outlet on the head closest to the rear of the ski directly overboard and plugging the exhaust were the water should go. has anyone else heard of this or know what reason or gains might be had apart from making the exhaust hotter?


  2. #2

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    I believe that it is a two fold reason.

    1. Dumping water overboard lowers the pressure on the water jackets allowing more water to flow due to less water pressure.... with more water flow, you get better cooling on your cylinders. This assuemes you need more cooling. Your enigne runs effeciently with water at a certain temp (I do not know what it is but I believe the water ought to exit the head at 110-120 degrees F).

    2. Less water to the exhaust pipe for cooling leads to hotter exhaust which will lead to a faster sonic wave in the pipe. This can potentially give you better rpms due to improved fuel scavaging from the exhaust. The GPR pipe is set up to run hot which is why people loose approx. 50 rpms when they replace the cat con (hot) with a "D" plate (cool).

  3. #3
    2000 GPRXP 4tec shooter98xpl's Avatar
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    nice info salty, thanks.
    SHOOTER

  4. #4

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    thanks salty

  5. #5
    African-American
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    How many of you guys are runnign this setup ?
    Last edited by spaceman; 01-20-2008 at 02:41 PM.

  6. #6
    krispaintballz's Avatar
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    Quote Originally Posted by salty View Post
    I believe that it is a two fold reason.

    1. Dumping water overboard lowers the pressure on the water jackets allowing more water to flow due to less water pressure.... with more water flow, you get better cooling on your cylinders. This assuemes you need more cooling. Your enigne runs effeciently with water at a certain temp (I do not know what it is but I believe the water ought to exit the head at 110-120 degrees F).

    2. Less water to the exhaust pipe for cooling leads to hotter exhaust which will lead to a faster sonic wave in the pipe. This can potentially give you better rpms due to improved fuel scavaging from the exhaust. The GPR pipe is set up to run hot which is why people loose approx. 50 rpms when they replace the cat con (hot) with a "D" plate (cool).


    Just a question that i thought of that was kinda related to the first
    answer. I know you are talking about pipes but here goes. Lets just say i have two 3/8" lines coming into the exhaust manifolds. Then i have two 3/8" lines coming out of the heads. Now i drill a third hole and tap it on the no. 2 cylinder. Ok now in theory this would i thought cause a neg pressure. I thought neg pressure causes gas or pockets in the head where water doesnt flow no pos pressure. Now is this true. I heard people doing this cause "they needed more flow". But does it. To increase more flow you would have to increase the lines coming in and going out while trying to keep a positive pressure. But not to much to start hurting the engine(leaks into the cylinder). Someone please clear this up. Myth or no? Common cures to get pos pressure? jets or restrictors?
    Thanks kris

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