Glenn:
looks to me like it should take about 1.5% of your total power at 9000rpm to
drive EITHER the water pump, the oil pump, or the alternator. In other
words, you should save about 1.5% of your horsepower for each one of those
you don't use the engine to drive. For a 1000hp engine, that's only 45hp,
total.
(The percentage goes up as the RPM goes up; I should be able to save about
2% for each "parasite" on my gixxer-- but then, that only gets me 5 or 6hp!)
The analysis I used was based on an engine with a single oil pump/ wet sump.
When you go to dry sump, you recover all those "windage losses", by taking
the crank out of that pool of oil. I have heard it argued by several
knowledgeable people that "what you gain in eliminating windage losses, you
give back in parisitic pump losses, because of the added oil pumps. If that
is true, then we should be able to account for the windage gain on an 8-cyl
engine (going to electric dry-sump system) by saying that you are going to
save all the power needed to drive the FOUR pumps on the dry-sump system.
In your case, that would be 4 X 1.5, or about 6%. On a 1000hp/ 9000rpm
engine, that would be 60hp gained for the dry sump system, and 15 each for
the electric water pump and for elimination of the alternator.
Worth it?
Russ, #1226B
p.s.-- these observations come from a graph and supporting text in
"Engines-- an Introduction" (J.L. Lumley)
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