I was hoping getting somewhere around 20 mpg. I think it's all power and weight. My 911 which I drive very hard all the time manages to get 22 mpg mix highway/local consistently. 3.4 liter engine, slightly smaller but entire car only weights 3000 lb.
In a large-engined, heavy, conventional vehicle there are two main things to concentrate on: - Conserving momentum: anticipate and leave a good buffer to avoid braking, time lights, time yields, use early neutral glides to stops, smooth out traffic waves. - Avoid idling: shift to neutral and stop the engine at long stops; avoid drive-throughs.
Yep, and on the latter, strongly consider face-out parking (Beating the EPA - The Why’s and How to Hypermile - CleanMPG Forums). Engine uses a lot of fuel when cold and less when it's warm. So, spend the time to back in or pull forward into a spot during low consumption. When consumption's high, you can start moving more quickly, esp. in a crowded parking lot. Also consider FASing while pulling into a spot, instead of pulling in w/engine on, shifting to park, turning key off.
You also have to take into account the wheel size. Aren't those 22" on the X5M? They're big, heavy and wide with sticky compound rubber.
hmm Are you standing in the right field on another diamond or something? He's in the US and everything he mentioned is in US measurement - MPG. Also you need to work on your math skills. Going from 14.7MPG to 15.4MPG only yield 4.76% increase. In Prius mileage that translates to going from 50MPG to 52.38MPG. Using your logic of 9MPG increase on a Prius would mean that his X5M would have increased from 14.7MPG to 17.346MPG. That's something he would have been more excited about.
The point that I was making was that he was trying to reduce consumption, so it made more sense to use consumption measurements than mileage measurements. I don't know about you, but I'm much more interested in how much fuel it takes to go where I want to go than how far I could drive given how much fuel I just purchased. I chose to use consumption units that were already in common use. Obviously I didn't explain it very clearly. Let's calculate consumption in American units. His consumption changed from .068 to .065 gallons/mile. He saved .003 gallons per mile. Using my example, if he'd started at a baseline 50 mpg (.020 gallons/mile) and saved that many gallons per mile he would have ended up at 58.8 mpg (.017 gallons/mile). That's how much fuel he saved by the way he altered his driving of his BMW.
While he was a bit unclear (and I didn't have enough caffeine before reading his post), he was also right. See the 'Gallonage' article that Cwerdna linked to this thread, and to many past threads. Our MPG scale causes a lot of problems among consumers who are not math fanatics. Switching to the Gallons Per 100 Miles scale, analogous to the liters/100km scale used by much of the rest of the world, would cure many misperceptions.
Thanks for the mileage report. I have to say I was impressed driving the Camry Hybrid right after test driving the Five. Not only did it have much better power, it was more comfortable too. Most noticeable besides the conventional dash that I liked was how much quieter it rode on the same pavement. Then I got back in our 2006 and was depressed by how noisy it was in comparison to both cars.
I really consider the Prius, even with its low-profile and maligned-by-some reputation to be the FLAGSHIP of the Toyota line. It really is exemplary. A remarkable combination of enough tech to make geeks drool, the energy-efficiency to turn the heads of the green-freak and the gas-miser alike, space to haul five, and the acceleration to beat most any road-legal car off the stop line. And if you really would like to know the math behind calculating aerodynamic drag, grade resistance, and rolling resistance, I can run the numbers for you. The mass factors directly into grade resistance and rolling resistance. Coefficient of drag and frontal area factor linearly into aerodynamic resistance. Velocity factors in exponentially (^2). Beyond that, it is all in the engine cycle used (some are more efficient than others), and the Prius' ability to store small amounts of energy in the traction battery that would have otherwise been wasted, and to dynamically turn the engine off and on when it is the most advantageous. At least in the current decade, it doesn't get any better.