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Old 04-03-2013, 07:29 PM   #51 (permalink)
elhigh
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Location: SE USA - East Tennessee
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Josie - '87 Toyota Pickup
90 day: 29.5 mpg (US)

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Quote:
Originally Posted by Nerys View Post
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the point of lowering the power is not to increase mpg by reducing alternator drag but to ELIMINATE the alternator and water pump drag all together and make the power consumption low enough that "charging" the battery is convenient and not a hassle.
<snip>
maybe your race car would be a toaster without its pump for a few seconds but I can go several MILES with no damage in a pump failure scenario in a metro. plenty of time to realize something is wrong stop and fix it.
It just crossed my mind that the 113ci engine in my Farmall fares pretty well without a water pump. It's a thermosiphoning engine, have you tried removing the water pump and the thermostat, just to see how it does? You might be able to get along with the thermostat in place, but maybe try it without first.

Granted the power output of the Farmall is pretty modest even compared to the lowly Metro, but still it's worth considering. Gotta be absolutely certain there isn't an air bubble or anything in the waterways, though.

Let me point out too that for best performance in a thermosiphon system, add some alcohol to lower the boiling point. Get some vapor (not air) bubbles to form in the system at less than the usual boiling point to lift liquid through the block. If you really wanted to get fancy with it, you'd install a couple of check valves in the top and bottom hoses to ensure that vapor bubbles would cause the entire engine's coolant system to act as a big bubble pump.

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Last edited by elhigh; 04-03-2013 at 07:35 PM..
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