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Old 08-27-2008, 01:19 AM   #18 (permalink)
dcb
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Example of pumping losses.

Just grabbing the first numbers I can find, a chevy 305 at idle:
assuming: 75 cubic feet of air per minute at 20 inches of vacuum

(75 cfm) = 2160 cubic inches per second

imagining a 1" square piston in a suitable "cylinder", it can lift 20 lbs, 2160 inches in one second. I figure that is about 6.54 horsepower in pumping losses at idle across the throttle plate. (1 hp = 550 foot*lbs/second)
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Last edited by dcb; 08-27-2008 at 01:26 AM..
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