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Old 02-21-2008, 07:14 PM   #5 (permalink)
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Let's set a price goal of $30 for this flow meter, that should filter the ideas.

we are talking about non OBD engines.
the marble or epoxy ball is pushed around a circular track by the gasoline.
an electronics guy can tell you to make a light tach to count the ball passes(fuel volume)
the distance is pulses off magnet on the axle or drive shaft u-joint with hall effect or other sensor, a junk yard crank or cam sensor.
the calibration is like any MPG meter, count the pulses per gallon, and the pulses per mile. there are other threads on this site that tell how to use an old lap top to do the computation. but since this is just pulses and you don't have to decipher pulse width, the electronic minded can tell you how to use a divider chip (terminology) and display.

Below a very rough sketch. Visualize this stuff stacked up together and clamped with 4 bolts. The holes thur the outside ring are small enough so the ball passes over. So does some fuel, but it doesn't matter just takes more pulses to make a gallon. Next try to think of materails that are gasoline and alcohol proof to make it out of. A 1/2"x3" aluminum plate and ball mill would be nice, but lets try to think of something even more common and less expensive. Like maybe cut a 5/16" length off a piece of 3" seamless tubing for the outside ring. And 2 1/2" for the inside ring.
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Last edited by diesel_john; 03-10-2008 at 02:00 PM..
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