... for short distances anyway!
As you all know, the new Q45 and M45 have this MPG page on the LCD display. Gives you a reasonably accurate assessment of mileage.
Although I tend to average about 16mpg or so in my M45, the other day I noticed that the reading was over 30mpg for one section that I reset the counter at. So, I went to a nearby long hill (Silver Creek Valley Road, east of 101, for those of you familiar with San Jose).
At the top of the hill, heading towards 101, I reset the MPG indicator at about 50 mph. The car gently accelerated down the slope (with my foot off the gas) since it is a decent descent. At about three-quarters of the way down, now doing about 70mph since I have not touched the accelerator pedal yet, my mileage registered 71.7mpg for that two or three mile stretch!
BY the time I reached 101, about four miles away, I was still showing an average of 51mpg. I was babying the accelerator to get the best mileage I could, without slowing below the speed limit (45mph).
Cool what us curious techno-geeks can do, huhn?