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pop-off

  1. #1
    I'm No Expert Shaun's Avatar
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    Default pop-off

    Well i think this topic should be unique, i cant remember ever seeing a topic about them other than you guys showing your installs. How do they work? From what i remember hearing from back in the day when i was a kid at the races that they where ment to open and releive intake pressure and keep the boat from getting wild. I'm curious how they work and is the main idea of them to keep the ass end from lifting up on shutdown and keeping the boat from hooking or are they to keep the intake pressure from getting so high that somthing bad might happen? Lets post alot of pics too! i like pics

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  3. #2
    no need 2 fake it. 84Condor's Avatar
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    granted i have been around it since a kid too, but i have always thought it was a combo of what you have typed there... other than the fact they look kickass but basically they unload the pump non-violently haha, thats my understanding at least.. somebody correct me please!
    "i'm into snatchin' kisses... and vice-versa!" haha

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    Amber Racing Services BUSBY's Avatar
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    When you are at full speed, your pump has a lot of water going into your intake. If your going fast enough, and your pump has enough intake pressure to lift the tail of your boat if you let out of the throttle or if your engine locks up (both basically stopping the impeller not allowing the water to go through the pump), then you should look at installing a pop off.

    A pop off for those of you who haven't seen them is a valve that installs where your hand hole cover goes. Once deployed, the water diverts out of the valve/hand hole access area instead of having to go thru the impeller and bowl.

    Shutting your ride down at 100+ without a pop off for some can be scary. Ask Tony (dirt lot wonder)

    Hope that helps.

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    Amber Racing Services BUSBY's Avatar
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    To understand how it depolys, either the driver pushes a button on the steering wheel right before letting out of the throttle, or a pressure sensor installed in the intake deploys the pop off at a set PSI.

    BB

  7. #5
    I'm No Expert Shaun's Avatar
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    On the pop off's i alwasy see a large line comming off the top of it, whats this for? I'm curious how the internals work.

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    Is a pop off valve better than a jetaway? Where do you get pop off valves?

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    Quote Originally Posted by trashman View Post
    Is a pop off valve better than a jetaway? Where do you get pop off valves?
    The pop off basically opens a hole in the pump which allows water to escape the pump thereby relieving pressure in the pump, it helps control the boat upon sudden engine shut down at high speed.

    The jetaway disconnects the engine from the pump if the engine should lock up at high speed allowing the pump to turn when the engine will not. It helps to control the boat upon sudden engine shut down at high speed. The jetaway also can be disconnected easily in the driveway to allow the boat to run dry without damaging the pump.

    Which one is better? Both.

    Where do you buy a pop off valve? I have no idea but I'd like to know.

  10. #8
    Amber Racing Services BUSBY's Avatar
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    Quote Originally Posted by hotrod56cars View Post
    Where do you buy a pop off valve? I have no idea but I'd like to know.
    From me

    Or Greg Shoemaker, MPD or Mike Miller (Red Rocket)

  11. #9
    I'm No Expert Shaun's Avatar
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    What do they run? Still no body to explain the interworkings?

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    Exclamation

    Thanks for the info .

  13. #11
    Senior Member cyclone's Avatar
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    Quote Originally Posted by Shaun View Post
    What do they run? Still no body to explain the interworkings?
    i paid 1100 for mine from Mike Miller for the valve itself and spent another 600 with mpd for the controls and air system.

    basically how it works is this:

    that big line on top of the valve is the exit line for the air that is stored above the piston inside of the popoff. the air pressure holes the piston down and closes off the hole in the intake. when the control valve is energized, the air is raplidly relieved from the valve and the water pressure in the intake pushes the piston upward, exposing the hole at the back of the valve. a large portion of the water that was trying to go through the pump now goes out the valve, pushing the back of the boat into the water.

  14. #12
    Boat Nut sleekcrafter's Avatar
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    Quote Originally Posted by cyclone View Post
    i paid 1100 for mine from Mike Miller for the valve itself and spent another 600 with mpd for the controls and air system.

    basically how it works is this:

    that big line on top of the valve is the exit line for the air that is stored above the piston inside of the popoff. the air pressure holes the piston down and closes off the hole in the intake. when the control valve is energized, the air is raplidly relieved from the valve and the water pressure in the intake pushes the piston upward, exposing the hole at the back of the valve. a large portion of the water that was trying to go through the pump now goes out the valve, pushing the back of the boat into the water.

    What brand are you using Cyclone? I see they are working very consistent these days, is it the pop-off, or the control system, doing this?
    Thanks in advance

  15. #13
    Senior Member cyclone's Avatar
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    Quote Originally Posted by sleekcrafter View Post
    What brand are you using Cyclone? I see they are working very consistent these days, is it the pop-off, or the control system, doing this?
    Thanks in advance
    mine is a miersch and works good and there are several others available. I saw an updated version of the Mills valve at the track last weekend that looked real good and the one Butch Thurlow is building is very nice.

    with most of the valves the control system and maintaining the internals are the key to reliability. Busby's controller is something i'd recommend if you want to have the valve go off automitcally if the intake pressure is too gnarly.

    I tend to stuff a ton of water into my pump and so i dont run the automatic deal but i know others that do sucessfully.

  16. #14
    Senior Member Red Rocket's Avatar
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    Quote Originally Posted by sleekcrafter View Post
    What brand are you using Cyclone? I see they are working very consistent these days, is it the pop-off, or the control system, doing this?
    Thanks in advance
    There are several operating systems available, some are co2 only and some are co2 and electric. Both types can be very consistent you just need to sure what you're doing and which parts you choose.

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