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Old 02-07-2015, 04:49 AM   #5 (permalink)
niky
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Scales were motorsports grade, unfortunately, they don't read to decimal places, even though they're accurate to fractions of a pound. I suggested correcting to whole numbers using small weights, but they didn't want to take the extra step... even though I tried to explain how quick and easy it would be.

Nothing in the cabin. No water, no snacks. No AC use, so water wouldn't condense around the AC evaporator, either. If the car got lighter due to evaporation from the radiator, then that's not our problem.

Quote:
Originally Posted by Fat Charlie View Post
Better? Fill up, drive, then fill up again with as few variables as possible- same pump, conditions, method, etc. Measure fuel pumped on the refill.
The first run was done that way. We needed several fills both pre- and post- to get exact numbers. Something that would be hard to do with two dozen cars.

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The method I've been most satisfied with was doing multiple fill-ups over the course of the run... then you get the median fill-up, as the first few tend to be off due to issues with the tank.

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Good if you don't have a line at the pumps. Last eco-run we had, the time spent waiting for the fill-up affected the numbers... which is how two diesel crossovers got 40-50 km/l on countback... because their high pressure fuel rails took a dump back into the tank while they were sitting parked.

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Personally, I would love to do this with a fuel cell. Or even a plastic bottle or bag like Mythbusters uses. I've seen a run done with a bottle mounted to the hood on a modern diesel... so it's possible, even with a high pressure fuel rail, but that requires a modified hood, so not practical to do with a lot of cars at once.

Last edited by niky; 02-07-2015 at 04:56 AM..
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