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Old 05-15-2009, 10:27 AM   #17 (permalink)
Master EcoModder
Join Date: May 2008
Location: Briggsdale, Colorado
Posts: 296

Wildfire - '96 Ford Bronco XL
90 day: 14.88 mpg (US)

Blackford - '96 Ford Bronco XLT
90 day: 20.26 mpg (US)

Y2k - '00 Honda Insight
Gen-1 Insights
Team Honda
90 day: 73.98 mpg (US)

Redford V10 - '01 Ford F250 Lariat
90 day: 15.64 mpg (US)

FireFly - '00 Honda Insight DX
90 day: 69.43 mpg (US)

LittleRed - '00 Honda Insight
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Just my opinion...

I have heard lots said about fuel cutoff when in gear and the throttle off. I have a hard time believing that the fuel is stopped completely. This would mean the engine is rotating with just the spark plugs firing.

I think what is really meant by fuel cutoff is that the engine is still being delivered fuel, but at the "idle" rpm fuel delivery rate. Anyone who has left the clutch out while decelerating knows that the engine will attempt to maintain idle speed once the idle rpm is met. The car will continue to motor on forever and a day on level pavement if you let it with the vehicle in gear and no throttle. You can essentially let the clutch out slow enough when completely stopped in first gear, and the engine will allow the car to accelerate to near idle rpm even though there is no throttle applied. This is also assuming the idle speed is set to factory specs.

Whether one decides to "glide" while in gear/clutch out allowing engine compression deceleration, or whether in neutral/clutch out and long coasting with the engine at idle speed, is up to the individual person. I know we can argue all day long about this topic, but it all depends on how one prefers to hypermile and the risks you are willing to take for the extra MPG.

Just my opinion - and I'm sure I will be proven wrong.
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