return line to gas tank

[jdzura at csc.com]

>If the pump draws 8 amps (@ 12 volts), and all of the heat from that winds
>up in the fuel (which it basically does , sooner or later), that is 96
>watts. Which converts to 327 BTU/hour. which is enough heat to raise the
>temperature of 10 gallons of gasoline about 7 degrees over the course of
>one hour if none of that heat is dissipated anywhere.

The power which goes into heat is significantly less than the power the pump uses
to push fuel. The way to determine how much electrical input power is converted to
heat is to convert the output flow of the pump to work. Then, calculate the
efficiency of the pump based on input power (96 Watts). The amount of energy not
directly used for pumping should be a fair approximation of  how much heat is
added to the fuel by the pump.

It is not simple to do, but I would guess that the pump must be 75-80% efficient.
Any thoughts on this?