Dave;
Amen to that. The only valuable information about a fuel pump (just like
a cooling fan) is the curve of its flow vs back pressure. Advertising
claims are worthless-- "500GPH" says nothing. Some types of pumps (and
fans) have a very steep flow/pressure curve; lots of flow into an open
outlet but the volume of liquid drops off dramatically as the output
pressure increases. It's like putting your thumb over the end of a
garden hose.
Other types of pumps, notably positive- displacement pumps, lose much
less flow as the back pressure is increased. These types have a
relatively flat curve. Hydraulic pumps fit into this category; a
centrifugal pump would be a poor type to use in a hydraulic system.
How many electric pumps also provide a family of curves-- not only flow
vs back pressure curve but curves for different DC voltages measured
directly at the pump? Only the quality manufacturers do that.
Those curves also show how keeping the wiring voltage drop low can boost
the output of your pump.
Regards, Neil Tucson, AZ
-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net] On Behalf Of Dave Dahlgren
Sent: Monday, March 20, 2006 1:01 PM
To: John Burk; land-speed
Subject: RE: Fuel Pump Flow
Without knowing the pressure the flow is meaningless. Basically you ne
0.5
lbs per hour at the required pressure plus line losses and the amout you
plan on bypassing so as to keep air and vapor out of the system. this is
for
typical gaolines. alky is approximately double the needed fuel. I have
never
run nitro so have no comment on that but double it again would not
surprise
me.
dave
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