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Old 03-01-2012, 04:59 PM   #274 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
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Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 53.47 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 73.57 mpg (US)
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That's probably an "it depends" answer.

Fuel cut (DFCO) deceleration means you'll go a significantly shorter distance than if you neutral coast while idling, so I doubt it's as effective as neutral coasting (because you need more fuel prior to DFCO to cover the same total distance).

I only DFCO when I *want* to slow down more quickly (ie. engine braking). (I don't drive much in hilly territory where I'd use DFCO as a technique to control downhill speed.)

I've never seen any controlled attempt to compare the two approaches. Besides, I suspect the results would vary greatly from vehicle to vehicle, which just makes it an "it depends" situation. No pat answer.
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