2 things happen during winter
1: air is colder, so interooler is much more effective, meaning engine can use more timing advance and get more power from the same amount of a given octane fuel
2: air is colder, so engine takes longer to warm up, using more fuel
additionally for me:
3: winter tires go on, they are thinner, better gas mileage
4: winter tires go on, they have more rolling resistance, better gas mileage cancelled out
5: winter conditions mean driving slower about 15% of the time, gas mileage goes way up, but can go down if the snow is deep enough
since i drive longer distances, 2 is inconsequential, and 1 helps, and 5 generally improves trip econ by 20%
my N54 mileage this winter was identical to that during the summer
|