Calculated MPG
Have read a number of posts, in different site forums, describing posters hand calculating their mileage. Some post that they record details at every gas-up and have kept meticulous records since t...
Forum Discussion
The other data useful is in recording engine hours as Average MPH is a better clue to vehicle use over strictly MPG. One divides odometer miles by engine run time to see what the days trip took as against clock time. (Zero idle time assumed).
Time spent at steady-state is lower than one expects. So, Average Speed and what you think of as Travel Speed start to diverge strongly when running too fast for conditions (lane-changing, use of throttle to do more than steady-state; ANY use of brakes save exiting road).
This is really about Quality versus Quantity. Going faster doesn’t mean one gets there faster (average speed may barely budge), but that the wear & tear penalties on vehicles and operator can’t be justified.
In the end the thing to have is GPM (Gallons Per Mile). When that varies 10% low (one has earlier found correct travel speed), then it’s an early indicator of mechanical issues to investigate.
As to the dash digital MPG read-out — as I know the variance with mine versus actual — re-set gives me a picture of changed winds. Run a touch faster or slower to maintain the standard GPM.
Other feedback devices (Engine Load Percent; or Manifold Pressure + EGT; or Vacuum + GPH) are helpful.
MPG records — alone — aren’t as useful without Average Speed + GPM.
A familiar route 323-mile day is right at 54-MPH Average and overall .066/GPM.YMMV
.
Time spent at steady-state is lower than one expects. So, Average Speed and what you think of as Travel Speed start to diverge strongly when running too fast for conditions (lane-changing, use of throttle to do more than steady-state; ANY use of brakes save exiting road).
This is really about Quality versus Quantity. Going faster doesn’t mean one gets there faster (average speed may barely budge), but that the wear & tear penalties on vehicles and operator can’t be justified.
In the end the thing to have is GPM (Gallons Per Mile). When that varies 10% low (one has earlier found correct travel speed), then it’s an early indicator of mechanical issues to investigate.
As to the dash digital MPG read-out — as I know the variance with mine versus actual — re-set gives me a picture of changed winds. Run a touch faster or slower to maintain the standard GPM.
Other feedback devices (Engine Load Percent; or Manifold Pressure + EGT; or Vacuum + GPH) are helpful.
MPG records — alone — aren’t as useful without Average Speed + GPM.
A familiar route 323-mile day is right at 54-MPH Average and overall .066/GPM.YMMV
.
