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  1. #1

    Pump Pressure Relief Mods...

    I know everyone has different opinions on where to put these fittings in the 2 inch spacer. Any input would be appreciated since Im about to do mine.

    Some are at 10 and 2, others are putting both on top, advantages/disadvantages of each???? Also are they directly the middle of the spacer or closer to the front or the back or does it matter????


  2. #2
    Duke's Avatar
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    Mine are in the 2" spacer at 10 and 2 for the simple reason of being easy to get to and not wanting to relieve pressure in just one area. The mod will let you have a lot more freedom on plate angles and optional trim tabs for speed runs. Also I installed a 1/8 NPT fitting for attachment to my pressure gauge for data collection on diff props and grates.

    Some people can get rid of the buck by changing angles and setups with the shoe. I don't have this kind of patience and want to be able to change my entire setup at a whim and not have to worry about all the small details. There may be some speed left on the table but I guaranty I will be riding the most and thats what really matters to me.

  3. #3

    Pump pressure

    So you dont use the pressure gauge all the time but you have it plumbed so you can use it when you want. I was just wandering if it mattered where they were drilled, if that affected pressure, etc. Another thing are they drilled and tapped with 1/8 pipe or 1/4 inch and did you weld a bung in the spacer for more room or just tap the material that is there???

    You hit the nail on the head with the riding part. I like to work and test the boat but sometimes time just doesnt allow for all that. I am also curious about doing speed runs only without the tabs and then going back the tab setup with the 1200 grate so I can pull some good holeshots. My boat has way to much low end power to take off with the 800 grate in any kind of drag race! And this is with power valves pinned!!!

    Thanks...

  4. #4
    Duke's Avatar
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    I used 1/4" NPT on the valves and 1/8 on the gauge. My gauge operates all the time I was just suggesting you add the fitting while you are for future if you want to add a gauge.

    No metal was added. It does seem thin there but the brass fittings torqued down nicely. On the inside the excess fitting was ground smooth to the aluminum spacer.

  5. #5
    Hydrotherapy's Avatar
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    [quote=Duke;424288]I used 1/4" NPT on the valves and 1/8 on the gauge. My gauge operates all the time I was just suggesting you add the fitting while you are for future if you want to add a gauge.

    damn i thought i was set with my 1/8 npt 90's looks like i will have to try to order some 1/4 npt 90's from the states,thanks for posting i was just about to tap the spacer at 10 and 2 with 1/8 npt that i had laying around for the relief job

    duke; can i get away with the 1/8 npt if i am using two valves rather than one, or now i'm ported will two be needed at a 1/4..
    Last edited by Hydrotherapy; 10-05-2007 at 12:50 PM.

  6. #6
    Duke's Avatar
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    [QUOTE=Hydrotherapy;424420]
    Quote Originally Posted by Duke View Post
    I used 1/4" NPT on the valves and 1/8 on the gauge. My gauge operates all the time I was just suggesting you add the fitting while you are for future if you want to add a gauge.

    damn i thought i was set with my 1/8 npt 90's looks like i will have to try to order some 1/4 npt 90's from the states,thanks for posting i was just about to tap the spacer at 10 and 2 with 1/8 npt that i had laying around for the relief job

    duke; can i get away with the 1/8 npt if i am using two valves rather than one, or now i'm ported will two be needed at a 1/4..

    Paul, I am sure you will be fine with that. 1/4" is probably overkill IMO.

    It has a 3/8" barb on the other end right?

  7. #7
    james k's Avatar
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    Hello Duke,i had seen Jims relief mod is yours primarily the same,or do you have any pics...Thanks James

  8. #8
    My son (mohawk man) jeffsntx's Avatar
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    The ID of an 1/8" NPT fitting is only 1/4". IMO, it is not going to releive enough pressure to do anything for you Paul. You can only move as much water as the smallest opening will allow.

  9. #9
    Hydrotherapy's Avatar
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    yes the 1/8 npt has 3/8 barb,well if thats the size tube we all use for jw valve..
    the smallest id of the 1/8 npt is 5.50mm or in your talk 0.2170 ,but i may be able to open it up to match the barb end id of 0.2820..

    whats the smallest id on the 1/4 npt if you have any laying to hand..

    hope the 1/8 npt are good to go as these are impossible to get in the uk...let alone the 1/4 fittings,had to pester carl for last lot

    man its hard trying to work over to inches i have a digital vernier and keep switching to know what you talking about from mm to inches
    Last edited by Hydrotherapy; 10-05-2007 at 01:13 PM.

  10. #10
    Duke's Avatar
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    The Jetworks valve has an ID of only slightly larger then 1/4". One valve and fitting was suffecient for an 82+ MPH run without any buck or bounce is the reasoning I had. Thats a great deal more volume then the tuners running holes in the shoe. Just figured 2 would be even better.

    If Jim did it the way we talked about his should be the same as mine.

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