08-18-2013, 07:00 PM
but when I rent a newer manual car or when I drive my Dad's car. the fuel consumption goes to 0.0 (0 L per 100 Km) when downshifting.
I don't understand this.
With an automatic transmission, you take your foot of the gas pedal to use the brake pedal (normally). Butterflies close, acceleration goes to 0, but gas is fuel is still consumed, the rate of consumption decreasing as the rpm stabilize at idle.
It *seems* to me that downshifting raises the rpm above what would be seen if the car/truck were left in a higher gear, at least until the rpm dropped to idle.
So where does the increased fuel economy/0 fuel consumption occur? I assume we're still talking about compression braking versus manual braking, right?
I drive an A/T car for the sheer convenience now. Given the weather, my general feeling is "Sticks are for kids", with appropriate exceptions.
However I do down shift for longish down hill runs. Easier on the brakes, less chance of fade, and for years, cars have idled at higher RPM than I like. (My feeling is a car shouldn't accelerate to +15mph on level ground just by taking your foot of the gas, but it happens.)
Everyone should learn how to double-clutch.
Uh, no.
I don't understand this.
With an automatic transmission, you take your foot of the gas pedal to use the brake pedal (normally). Butterflies close, acceleration goes to 0, but gas is fuel is still consumed, the rate of consumption decreasing as the rpm stabilize at idle.
It *seems* to me that downshifting raises the rpm above what would be seen if the car/truck were left in a higher gear, at least until the rpm dropped to idle.
So where does the increased fuel economy/0 fuel consumption occur? I assume we're still talking about compression braking versus manual braking, right?
I drive an A/T car for the sheer convenience now. Given the weather, my general feeling is "Sticks are for kids", with appropriate exceptions.
However I do down shift for longish down hill runs. Easier on the brakes, less chance of fade, and for years, cars have idled at higher RPM than I like. (My feeling is a car shouldn't accelerate to +15mph on level ground just by taking your foot of the gas, but it happens.)
Everyone should learn how to double-clutch.
Uh, no.