[Rich807]

Just an observation post....

Been tracking my mileage since I got my X2 a couple of years ago now.

My X2 is my daily driver & running the same route year-round I average 2-3mpg better each tank of fuel when it's the time of year I don't have to run the A/C in the car.

I'm surprised that the # isn't more like 1/2 or 1 gal better vs the 2-3 mpg.

Happy X2 motoring everyone!

[chowser51]

For me when A/C isn’t running, heat is. My mileage sucks because I have a lead foot and keep it in sport all the time. Lol

[Rich807]

Curious. Do you allow the A/C compressor to be on/active when using heat mode? If you manually turn off the A/C compressor when you need heat mode (but don't need the dryness of heat run through the A/C system) I'd bet you'd see a reduction.

[//TMT]

Originally Posted by Rich807

I average 2-3mpg better each tank of fuel when it's the time of year I don't have to run the A/C in the car.

This might be because of the US Winter fuel formula changeover, in addition to cooler ambient temperatures, not the use of A/C. Where do you live? The regulations vary a lot and the details of the formula used in your area, combined with how the engine programming reacts to the change, make all the difference.

When do you see the increase, maybe around late September? When does it disappear, around late May? Those are the typical changeover dates, adding some time for the low-volume stations to show.

[Rich807]

I live in Vegas & typically we get our fuel here from California (wish was not the case but it is what it is).

I definitely see a drastic difference in fuel economy directly related to how much I have the A/C compressor running. For instance, as soon as it's cool enough in the mornings to commute in without use of A/C, I see a gain in MPGs. Then, when it finally gets cool enough to go both to & from work without A/C, I see another boost in MPG.

My S-Drive 28i is definitely the most A/C MPG affected car I've ever owned in 3+ decades.