Fewer than 3% of cars sold in the U.S. have manual transmissions

Re:Fewer than 3% of cars sold in the U.S. have manual transm... by lmm on Thursday November 17, 2016 @09:29AM (#12977691)

> The engine will be turning over at ~1000rpm instead of 2000rpm in my diesel.

Right, but when you're coasting you're burning fuel to turn over, unless you have a perpetual motion engine. Whereas engine braking (on a car with an ECU i.e. one made since 1996 or so) you could be doing 2000rpm but burning no fuel (gravity is turning the wheels which are turning the engine).

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Re:Fewer than 3% of cars sold in the U.S. have manual transm... by luca_ing on Thursday November 17, 2016 @10:04AM (#12977981)

> (gravity is turning the wheels which are turning the engine).

... which brakes the car, so you still lose energy.

Can't find literature at the moment, but ISTR that the valve train can take several kW to operate.

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Re:Fewer than 3% of cars sold in the U.S. have manual transm... by lmm on Thursday November 17, 2016 @10:08AM (#12978016)

Sure. Turning the engine is going to take energy one way or the other. But you can use energy that would otherwise be wasted heating up the brake pads rather than energy from burning fuel.

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Re:Fewer than 3% of cars sold in the U.S. have manual transm... by luca_ing on Friday November 18, 2016 @10:54AM (#12987579)

I think the alternative was coasting, not braking.

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Re:Fewer than 3% of cars sold in the U.S. have manual transm... by lmm on Friday November 18, 2016 @03:54PM (#12989987)

So if you're coasting you're spending fuel to increase your speed (relative to what you'd do by staying in gear). In the situation where you're considering coasting that's probably not a tradeoff you want to be making.

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