Quote:
Originally Posted by UltArc
That is, I imagine being in gear (with injectors off) still uses SOME fuel, and it will take longer to get somewhere (with the added engine resistance).
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Actually, it uses 0 fuel. Looking at GPH, once my ultragauge goes into open loop, I'm using no fuel at all... and in my car, the displacement is so small that 5th gear really does not hold you back all that much. It
does, but not like my old 4-liter Ranger did. Don't get me wrong, I understand your point and agree with you, I'm just sayin; I can coast pretty damn far in 5th.
Quote:
Originally Posted by riva2model64
they would have to know the gph of their engine in neutral. The only thing slowing down the car in this case is tire rolling resistance which is pretty negligible, and air resistance which is negligible at lower speeds.
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Speaking again about my car, I idle at .13-.15gph, depending on whether my lights are on or not. It only takes a moment for my fuel consumption to drop to that level when shifting from gear to neutral. As for air resistance, if I recall correctly, aero drag still accounts for 30+% of your fuel used at speeds below 40 MPH.
Quote:
Originally Posted by riva2model64
When coasting in gear with the injectors off, I don't think it uses any fuel, however you lose speed due to the added drag of the engine being connected to the drive wheels.
Therefore, without recording any test data, I hypothesize that coasting to a red light or stop sign is far more efficient while coasting in gear vs. coasting in neutral.
I also hypothesize that given a situation where one will coast, then step on the gas again, coasting in neutral may potentially be more fuel efficient than coasting in gear because one will have to accelerate less due to a lower loss in MPH coasting in neutral. Though, without knowing the numbers, either form of coasting may be more efficient depending on the situation. One would also need to know when the ECU turns off the fuel injectors.
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This all sounds pretty good to me
Cheers
~Matt