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Head pressure does not cancel out in a closed system. The 'head pressure' becomes the pressure rise across the pump from the intake to the exit. It is what makes the fluid flow through the rest of the system. The pump has a pump curve that starts at zero flow and max pressure rise across the pump and drops as the flow increases, and the system has a flow curve that starts at zero pressure drop at zero flow and rises as the flow increases. When the two pressure values are equal, that establishes your flow rate.
Bill Schertz
KIS Cruiser # 4045
----- Original Message ----- From: "Jim Sower" <canarder@frontiernet.net>
Rusty,
I only heard today that Al G. had flow data on his dyno. He might have some ideas around this. As to head pressure, I believe I was taught that head pressure only exists in an open system. In a closed system it all cancels out going around the circle.
But that was a long time ago ... Jim S.
Russell Duffy wrote:
What we
need is some expire mental measurement of flow rate under actual
conditions (which will involve a flow meter in the system) and then,
with the engine at rest (the pump is the only moving part in the
system), we can see how much current it takes to achieve that flow rate.
Sadly, the pivotal instrument, a flow meter that doesn't disturb the
system too much, is probably not available. If someone could come up
with a flow meter in a 1.25" line, we could do some expirements.
Other than that, we're guessing at numbers like PL and the bumblebee
folks ... Jim S.
I agree. Everyone keeps talking about all this head pressure that the pump is having to face. It must be stealth pressure, because my pressure gauge doesn't see it.
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