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Thread: ULT minimum pressure?

  1. #1

    ULT minimum pressure?

    Out of pure curiosity, what is the absolute lowest pressure required to allow the ULT to work properly? As in, minimal risk of short stroking.

    Thanks all.

  2. #2
    Join Date
    Sep 2008
    Location
    Ohio
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    4,507
    Pull pressure?

  3. #3
    Return pressure

  4. #4
    It varies so much marker to marker there is no way to tell you that, really.

    Its not recommended for classic, but some people have success just dropping it in, some dont.

    An x valve or any of its variants regulate to 600 psi or so, the classic is around 400 psi...

    So if I were to give you a direct answer... 600 psi, thats what it was designed for

  5. #5
    Cool. Thank you. It's just a random question that popped in my head. Lol.

  6. #6
    Join Date
    Oct 2006
    Location
    Houston, TX
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    3,175
    A properly working x-valve/RT valve will be switching bottle pressure to the top of the on/off at the point it needs to reset. That puts you at 800 psi at a minimum normally. The chamber pressures don't actually vary that much except with the bolt type, with the level 10 being about 50 or 75 psi higher (it's in here somewhere). Depending on velocity, bolts, paint and barrels, they run between 400-500 psi on the final dump chamber pressure, but a shutoff RT valve - ULT on/off will be sitting at bottle pressure.

  7. #7
    Join Date
    Jul 2011
    Location
    United Kingdom
    Posts
    344
    My x-valve + ULT stops cycling at around 800psi

  8. #8
    Quote Originally Posted by Spider-TW View Post
    A properly working x-valve/RT valve will be switching bottle pressure to the top of the on/off at the point it needs to reset. That puts you at 800 psi at a minimum normally. The chamber pressures don't actually vary that much except with the bolt type, with the level 10 being about 50 or 75 psi higher (it's in here somewhere). Depending on velocity, bolts, paint and barrels, they run between 400-500 psi on the final dump chamber pressure, but a shutoff RT valve - ULT on/off will be sitting at bottle pressure.
    If the ULT on off is sitting at bottle pressure, would the trigger pull feel different between tanks that are putting out differing pressures, say a ninja shp at 1100 psi vs a regular 800 psi tank?

  9. #9
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
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    7,351
    Quote Originally Posted by The Ritual View Post
    If the ULT on off is sitting at bottle pressure, would the trigger pull feel different between tanks that are putting out differing pressures, say a ninja shp at 1100 psi vs a regular 800 psi tank?
    No. The ULT only sits at bottle pressure in a retro valve following a shot. At this time the larger top diameter has full bottle pressure applied to it unlike the classic valve that always has the regulated chamber pressure on its top following a shot. When the on-off is opened and the front chamber is fully charged and ready for a shot, the lower regulated pressure is all that is available and it only applies to the smaller diameter of the pin since that is the size of the hole exiting the lower portion of the on-off assembly. This pressure is the one that is pushing down on the pin and interacting with the sear and trigger rod. Therefore, the trigger force force is the same for both the classic and retro valves, since they operate at the same pressure from a firing point of view.
    Except for the Automag in front, its usually the man behind the equipment that counts.

  10. #10
    Yeah. The RT slam fills the dump chamber at full bottle pressure, but regulates down after it's filled. That's why you get more reactivity with higher pressures, but the trigger weight won't change.

  11. #11
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
    Posts
    7,351
    Quote Originally Posted by brokeass_baller View Post
    The RT slam fills the dump chamber at full bottle pressure, but regulates down after it's filled.
    It regulates during the fill process. The chamber filling process starts at full bottle pressure and pressure regulation feedback is on the chamber side of the on-off assembly. The input air passage is closed off as the chamber pressure reaches the preset value for the desired velocity.

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