This is curious to say the least. Why do I say that? Well, a far as I know,
the oil pump, either dry or wet sump, is a positive displacement pump. So at
low rpms, turning by hand, they do not produce much output nor at any
pressure (unless you are turning it by hand against the internal engine
clearances). As speed goes up, so does the volume. Then it hits a spot where
there is more oil than can be spread through the clearances and the pressure
goes up. So it now has to bypass oil somewhere or the pressure just keeps on
going up until the shaft breaks or some other nasty happens. And because the
volume of oil goes up as a functio of rpm it take more power as a function
of rpm even when bypassing oil. So if you wanted to use an electric motor to
drive the pump, IMO, you would need to figure the volume of oil at speed and
the pressure and then size your electric motor to that requirement. Same
sort odf consideerations for electric water pumps. The belt driven one uses
more power because it has to actually pump more water against a rising head
pressure, hence more power equired at speed. Your motor does not need all
that so the power is wasted. An electric pump can pump 35 gpm at a pressure
to keep nucleate boiling from happening and this results in a fairly small
electric motor to drive the water pump.
Now having said that, and you may all disagree, I would never run an
electric oil pump drive. Fail an electric water pump and the engine can
still be saved. Fail that electric oil pump and you may have to use that
motor as a boat anchor. Not worth it in my book..
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