A lot of it boils down to the driver and the type of driving. For much of my car's life, it has averaged around 10L/100km. Worse when I was on it more, or in more stop and go traffic. Some of my poorer mileage tanks went at about 12L/100km. And some of the better under 8L/100km or over 30mpg (cruise control at 105km/h for 800+km
).
I have since moved out of downtown Toronto to the "burbs", and my commute now is mostly ~80km/h with very little traffic, and lately I've been getting mid to high 8L/100km. Basically picked up 5mpg without changing my driving at all, and it all being in the difference of roads/area. I don't get to go fast enough i.e. 120km/h where drag hurts economy, but fast enough, that I get into 5th gear, and basically put around 2000rpm for long stretches of straight road. And this is still with getting the ass out on almost every commute. If I put in a little effort, I should be able to get under 8L/100km, or almost 30mpg on every tank.
Oh, I know what must be helping the mileage too . . . I've turned off my cat over temp protection, and run really "lean" (stoich, which is lean if you think about it under traditional tuning, but with DI these days, you can totally get away with it, which is why the Mazda Skyactiv is pretty good on gas . . . that and the high compression) under light load conditions, and then fatten it up as the boost rolls in.
