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"Accelerate gently" Nope. Absolutely incorrect. Best fuel economy is to accelerate rather strongly to cruising speed, getting into top gear quickly. BMW studie

by fnj 10y ago

"Accelerate gently" Nope. Absolutely incorrect. Best fuel economy is to accelerate rather strongly to cruising speed, getting into top gear quickly. BMW studied this when they brought out the 528e, and found something like 70% throttle is most efficient for this purpose. Upshift at moderate rpm, to be sure, but dawdling in the lower gears taking forever to reach top gear is a waste of fuel. You don't waste fuel accelerating. Fuel is being converted into potential energy. You waste fuel every single time you touch the brakes. That is turning potential energy into heat. All your other points are spot on. Most of all, drive way ahead! As soon as you see that light change to red far ahead, let off the accelerator and start coasting. Tire pressure is important. People look at me cross-eyed when I tell them I run 40+ psi, but it makes a big difference, and my tires do not wear in the middle.

stillworks 10y ago
> Best fuel economy is to accelerate rather strongly to cruising speed, getting into top gear quickly I have noticed that if I am accelerating strongly then up shifts happen between 2500 and 3000 rpm, otherwise the up shifts happen very much at 2000 rpm. Once I am in one of the upper gears then I tend to avoid heavy footing and accelerate gently. I noticed if use a heavy foot, the box tends to down shift. This I have noticed in just the plain vanilla D mode and not Sport mode which tries to shift at top of the rev range. I don't regularly use the Sport mode. On typical motorway driving, I keep at 70mph to 75mph between 2300rpm to 2500rpm. That is the rpm range and speed at which I have been able to get 40+ mpg. I could try the "strong acceleration" theory and see if I get any better mileage... but I guess I won't see a massive improvement. > People look at me cross-eyed when I tell them I run 40+ psi Interesting. How far above the manufacturer spec is that :-) My car is a touring/estate/wagon style and the due to the extra weight, the rear tires are rated at 2.5 bar / 36 psi ! Which I personally find to be very high. But I stick to the manufacturer specs. Depending on how quickly you change your tires you may not notice the wear. I am too paranoid about driving on sub-par tires and so far have stuck to changing all four tires after 24 months.

by fnj 10y ago

stillworks 10y ago

> Best fuel economy is to accelerate rather strongly to cruising speed, getting into top gear quickly I have noticed that if I am accelerating strongly then up shifts happen between 2500 and 3000 rpm, otherwise the up shifts happen very much at 2000 rpm. Once I am in one of the upper gears then I tend to avoid heavy footing and accelerate gently. I noticed if use a heavy foot, the box tends to down shift. This I have noticed in just the plain vanilla D mode and not Sport mode which tries to shift at top of the rev range. I don't regularly use the Sport mode. On typical motorway driving, I keep at 70mph to 75mph between 2300rpm to 2500rpm. That is the rpm range and speed at which I have been able to get 40+ mpg. I could try the "strong acceleration" theory and see if I get any better mileage... but I guess I won't see a massive improvement. > People look at me cross-eyed when I tell them I run 40+ psi Interesting. How far above the manufacturer spec is that :-) My car is a touring/estate/wagon style and the due to the extra weight, the rear tires are rated at 2.5 bar / 36 psi ! Which I personally find to be very high. But I stick to the manufacturer specs. Depending on how quickly you change your tires you may not notice the wear. I am too paranoid about driving on sub-par tires and so far have stuck to changing all four tires after 24 months.