Fuel Economy
GOAL: In running this test I had two goals in mind: 1) to get as accurate measure of the Frontier's gas mileage as possible, and 2) to determine whether the use of premium fuel would provide better economy than the use of 87-octane gas.
METHOD: Since the test could not be conducted in a laboratory, I wanted to keep the variables as consistent as possible. Here is the routine that I used to do so:
| -The route was a 210-mile loop
that I drive 1-2 times per week to work on a ranch in a neighboring
county. It is 80% rural highway, passing through two small towns
with only a couple of stoplights to contend with. About 30 miles
of the trip involve travel over gravel road and rutted pasture road. -All fueling was done at the same pump at the same station. I used a slow fill and pulled the nozzle at the first click. I filled at the start and end of each trip so that none of my personal driving was counted and only driving over the test route was involved. At each fill-up I recorded the amount of fuel pumped to the nearest 1/100 gallon and the miles driven to the nearest 1/10. -Each trip was made, to the best of my ability, at the same speed. I drove at posted speed (65-70) on the rural highways and about 30 mph on the gravel roads. Cruise control was used on all highway travel to ensure consistency. -I made 5 trips (1050 miles) using 87-octane fuel and recorded the results, then switched to 93-octane. I drove for a coupe of days to allow the ECM to adjust then recorded 5 trips using the premium fuel. -Some variables such as wind speed and direction, ambient air temperature, and traffic lights were beyond my control. There were no extremes of any of the aforementioned during any trip, however. |
RESULTS: Using 87-octane fuel for 1050 miles yielded an average fuel economy of 20.92 MPG. Switching to 93-octane fuel did produce slightly better economy at 21.31 MPG, but that difference is probably insignificant and within the margin of error given the uncontrolled variables.
MY CONCLUSIONS: As always, your mileage may vary. I believe that these are very respectable results for a fairly heavy truck with 265 horsepower and automatic transmission. I did note that pure highway mileage at 70 MPH appeared to be 21-22 mpg, which is actually better than the EPA estimates. Cruising at 65 MPH was even better. I noted with interest that the trip computer was very accurate, almost always showing mileage figures within 0.1-0.2. My particular truck seems to operate happily on 87-octane fuel, so the small (1.4%) increase in economy delivered by premium fuel is certainly not worth the 8-10% price differential.