I can't dispute your data, but the idea that higher altitudes automatically result in higher mileage because of less gas use in the thinner air is faulty. Yes, the air is thinner, but to get the same amount of power, the engine has to ingest more of it to make the same horsepower so to maintain the same speeds, the rider opens the throttle more. If the FI system is working as it should, the amount of actual fuel used is the same for any given level of horespower. Now if you hold the same throttle settings at altitude as you would at sea level and slow down, yes, that would result in better gas mileage, but few riders do this.Langolier said:Bingo, It does have a lot to do with altitude. I'm at 753ft above sea level and getting an average 40mpg. Higher elevation 5000 + I get about 50 - 52mpg. Thinner air = less oxygen = less gas mixture = less gas used = (less horse power).
There is a very slight advantage in that aero drag is reduced at elevation, but for reasonable elevations, the effect is pretty small (about 5% less aero drag 5K feet at typical highway speeds) and would be almost impossible to see in one's mileage unless you kept very careful records over long periods of time.
- Mark