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Al Gietzen <ALVentures@cox.net> wrote:
The case for EWP for example is performance. PL insisted that an EDWP
absorbs over 10 hp at 6000 rpm. He is probably damned close. He then made
the unfortunate leap that therefore an EWP must absorb the same power. Not
true. EWP conservatively absorbs 14V x 5 A = 70 W =~ 0.1 hp. He was off by
about two orders of magnitude or about 9.9 hp. Don't know about you but I
can always use an extra 9.9 hp.
PL may have been considerably off; but at .1hp with the EWP you will be
getting only a fraction of the flow of the belt driven pump; even if it were
100% efficient. Keep in mind that converting power into electricity is
about 85% efficient, as is converting electricity back into power. 0.85 x
0.85 = 0.72; so you have lost 28% of the power in the process. Pumping
coolant against even a small pressure head takes power. Any 'performance
improvement' you may see with EWP vs belt driven pump comes from lower flow
rate. Al
But, Al, that's the whole point. The stock pump is designed to provide adequate cooling in stop-and-go traffic; it wastes a lot of energy at cruise RPM. If the losses due to conversion are 25%, that still a *net* 7.4 HP gain - nothing to sneeze at. Add to that, that the coolant flow is tailored to the actual requirements of the engine, and that the thermostat can be eliminated, and the EWP has a lot to like.
Dale R.
COZY MkIV #1254
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