Another fuel mileage thread

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1,101
Location
PEARL River la
Thread starter
How do you get your fuel mileage numbers? I keep track of each tank and use lie o meter as a guide. I was looking at trends today and realized that I can't seem to find an accurate way to do fuel economy. I have done the manual way of calculations only to realize that tank pressure change never comes into play nor does angle of the car. There are so many factors that are out of my control. I put almost 600 miles on vehicle over last couple of days with meter stating 26.8 with 400 miles on this tank and still 1/4 tank left so by far my best tank mileage. I have had lowest tank of 250 miles couple of months ago. EPA estimate is 17 city and hwy 25 or average of 20 which over 9000 miles is 20.1 so I am meeting those numbers. Might be better to just enjoy the vehicle for what I bought it for and fuel economy wasn't high on the list. 2018 Grand Caravan 12800
 
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2,165
Location
Flaherty, KY
I always do the mileage since last fill-up divided by number of gallons to fill. Math never lies, this should be as accurate as one can get without getting scientific. Most gas stations will have the pumps on level ground, I've never considered that an issue. I use the Fuelly app to record every fill-up, so I have a record going back years of gas mileage. I also use the app to schedule and record maintenance.
 
Messages
591
Location
Atlanta, GA
I use Fuelly app and cross reference against the car computer. My TDI's are 1.2-1.7MPG optimistic vs Fuelly. Of all the cars I have owned with car MPG displays my Mazda's were always the closest, if I did purely freeway trips in my Mazda the trip computer was within .1-.2 MPG of hand calculated. Even 100% city driving tanks I was still within .8-1 MPG of trip computer.
 
Messages
470
Location
KS
i have stock 2016 frontier V6 auto trans. this last batch was 1,599 miles. 150 to 180 miles on each tank. with 10 fill ups. 3 was 20.1 mpg. 7 was 18. to 17 mpg. i can account the 20 mpg as high way miles.
 
Messages
2,213
Location
Lyndhurst NJ
I also use Fuelie to track the diesels economy. Surprisingly, the GL is off by a fair amount. The ride home from SML showed 23.2mpg, 7 hours, 485 miles on the short term display, but when I refueled about 100 miles later a few days later, the app showed 24.8 for the tank of 575 miles.
 
Messages
2,618
Location
High Tax Illinois
Jan 1 2020 write down odometer with a full tank. Keep track of all fuel put in tank, doesn't matter full or not, just keep track of gallons. Next Jan 1 2021 total your gallons used with the last filling the tank. Total miles divided total gallons gets you 1 year of MPG. This is the easiest way to me.
 
Messages
950
Location
Battle Creek, MI
Originally Posted by Quattro Pete
Originally Posted by tiger862
How do you get your fuel mileage numbers?
Miles divided by gallons. is there any other way?
Kilometers divided by liters?
 
Messages
39,420
Location
Great Lakes
Originally Posted by SVTCobra
Originally Posted by Quattro Pete
Originally Posted by tiger862
How do you get your fuel mileage numbers?
Miles divided by gallons. is there any other way?
Kilometers divided by liters?
Not too many people measure fuel economy in kilometers per liter. Now, liters per 100 km, that's for sure. smile
 
Messages
1,411
Location
Western Canada
Liters per 100 km is the official Canadian measure. Pumps dispense fuel in liters, priced per liter. Car speedometers are in kilometres per hour, road signs / distances are in kilometers. However ... You would be amazed at how many older Canadians still think in miles per gallon. ( US gallon or Imperial ... lets confuse things even more ). Yet, most of them have NEVER bought a gallon of gas, or driven distance measured in miles ... Canada has been metric for about 40 years now. Strange. I have always thought of fuel economy as how much gas do you use, not how far you can drive. The liters per 100km is, IMO, a super clear way to measure fuel economy. Less gas, better economy. More gas, worse economy. Some city figures ... My small, efficient Mazda2 uses about 7.5 liters per 100 km. That is 33.6 mpg US. Very good. The Subaru is about 11 liters per 100 km. Or 22 mpg US. So so. The Honda Pilot is about 14 liters per 100km. Or about 17 mpg. Not great ... unless you trust the computer, which is typically off by 2 or even 3 liters per 100 km.
 
Messages
844
Location
Wash, DC
The dash display with current Tucson consistently reads 7% higher than measured the traditional way. Best mileage was on vacation on Maryland's Eastern Shore: 34.4mpg. Flat rural roads, 50-60mph, no AC. Same with previous cars: 2006 Toyota Matrix 36mpg, 1988 Accord 37mpg. Now typical tank is 26.x mpg, average speed 18mph. Mostly city driving. Occasional hwy trip 30-32mpg.
 
Last edited:
Messages
1,101
Location
PEARL River la
Thread starter
Originally Posted by tiger862
How do you get your fuel mileage numbers? I keep track of each tank and use lie o meter as a guide. I was looking at trends today and realized that I can't seem to find an accurate way to do fuel economy. I have done the manual way of calculations only to realize that tank pressure change never comes into play nor does angle of the car. There are so many factors that are out of my control. I put almost 600 miles on vehicle over last couple of days with meter stating 26.8 with 400 miles on this tank and still 1/4 tank left so by far my best tank mileage. I have had lowest tank of 250 miles couple of months ago. EPA estimate is 17 city and hwy 25 or average of 20 which over 9000 miles is 20.1 so I am meeting those numbers. Might be better to just enjoy the vehicle for what I bought it for and fuel economy wasn't high on the list. 2018 Grand Caravan 12800
www.fuelly.com/car/dodge/grand_caravan/2018/rtoney862/847880/fuelchart By using this I was able to confirm the oil was the problem with fuel mileage.
 
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