MikeInNH Quote: Are you talking about the cars MPG computer?? If so…stop using it. They are notoriously inaccurate." Unquote
I find that our mileage computer result is good to within + - 5%. I have compared the results to a manual calculation.
I will refine your “BEST way” as follows: Refill your tank at the same pump with your car parked in the same direction at least three times to establish a trend before relying on a manual calculation.
I find that our mileage computer result is good to within + - 5%. I have compared the results to a manual calculation.
And I guarantee you I can find the exact same car and year where the trip meeter is more then 10% off. There are just too many variables for those things to be accurate. Change your driving habits a little…and it may be close to 10% off.
As I mentioned before an MPG display doesn’t have to be accurate to be useful, it only needs to be repeatable.
If it’s off by 20% time and time again and some problem changes the MPG it will be noticed.
“There are just too many variables for those things to be accurate”
?? The computer is metering the precise amount of gas needed for each cylinder, and the odometer serves up the miles. Sounds pretty accurate to me, if calibrated correctly. And certainly very repeatable.
I have many years of 10% ethanol use accurately compiled on line graphs & total mpg recorded for 3 cars. I also have many years of 100% gasoline(ethanol free) use accurately compiled on line graphs & total mpg recorded for those 3 cars. 100% gasoline has increased mpg by 8%, 7% & 5% in all three cars, as well as causing all engines to run smoother, quieter & with a bit more low rpm torque, so less down-shifting is needed to ascend hills. If you have a 14 gallon gas tank, its like adding 1 extra gallon to increase your range & being able to pass up more gas stations before you fill up! My new Hyundai Elantra(epsilon lyrae), bad mouthed by many drivers for bad mpg, got 43mpg on its first tank of 100% gasoline & is now averaging 38.9mpg. When Elantra drives on a section of the new “quiet pavement”, its like a magic carpet ride of quietness.
With 10% ethanol I would expect a maximum drop in mileage of 3-5%, and a similar increase when switching from 10% to regular gas.
Docnick wrote:
With 10% ethanol I would expect a maximum drop in mileage of 3-5%, and a similar increase when switching from 10% to regular gas.
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litesong wrote:
You consider the difference in energy between 100% gasoline(ethanol-free) & 10% ethanol blends only. Gasoline engines tho, are designed & built to burn 100% gasoline efficiently. EPA tests gasoline engines with the equivalent of 100% gasoline & vehicle manufacturers like that, since 100% gasoline gives the best mpg. Ethanol burned in gasoline engines, not only lose the btu energy battle, but gasoline engines are not set to burn ethanol as efficiently as gasoline.
Ethanol engines, which have high compression ratios(like INDY cars) compared to gasoline engines, need ethanol to get their best efficiency.
You do not believe I have years of comparisons between 100% gasoline & 10% ethanol blends for 3 cars.
Mexico (Pemex) sells 100% gasoline. I drive many miles in both Mexico and the U.S. in the same car, a Ford Crown Vic, and I have not been able to detect any difference in fuel mileage between E-0 and E-10 motor fuel…If there is a difference, it’s not enough to worry about…
What does make a noticeable difference in fuel mileage is wind velocity and direction and of course cruising speed…
It would be interesting to know if Mexican gasoline with no ethanol has the same energy content per gallon as US gasoline with no ethanol.
The Mexican and US 100% gasoline will have the same energy content. The only thing you can add to 100% gasoline to significantly change energy content is ethanol. The liquid hydrocarbons in gasoline all have very similar energy content per gallon.
Caddyman coughed:
I have not been able to detect any difference in fuel mileage between E-0 and E-10.
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litesong wrote:
With a decade of records, my 3 gasoline engined cars get 8%, 7%, & 5% better mpg with E-0. Your in-skull calculator don’t calculate well. My 3 engines are smoother, quieter & have a bit extra low rpm torque, too. My new 2013 Hyundai Elantra, bad mouthed for poor mpg, averages 39+mpg, with highs of 43 & 42.5, maybe higher to come. Its sssmmmooooooottttthhhh!
Less you don’t like my car gasoline records, I had my cycle accident that nearly killed me. Road after that, but finally gave it up, after the cycle gave it up.
Go to pure-gas.org for addresses, details, & a great zoomable map to find 7250+ sources for 100% gasoline.
Thanks for the update. That’s consistent with ethanol having a little less energy per gallon than gasoline. Ethanol containing gasoline might still be a better value in terms of $$/mile, depending on its reduced price compared to pure gasoline.
No. Accurate 87 octane E0 delivers 8%, 8%, 7%-8%, 7% & 5% better MPG than inaccurate, but “designated” E10, showing that the btu difference between the fuels ISN’T the only factor. Inaccurate, but “designated” 87 octane E10 has no ethanol or gasoline components that are 87 octane, which gasoline engineers accurately designate as the most efficient fuel for 87 octane gasoline engines.
The MPG computer in my 2010 Kia Forte has always matched the manual check.
Mine have been pretty accurate too. I’m trying to remember but I went for a couple years without a working gas gauge in one of my Rivs. I had the tank changed and they wrecked the sending unit. Somehow, the computer still calculated mpg and miles to empty. I think it was based on the injector pulse or something. So just relying on that, I always knew how much gas had been used but just not how much was left even though the low fuel light was on constantly. I just filled up every day anyway. Fixed when they had to put a new pump in.
What update?
you replied to a 6 year old thread.
Got me again. Time goes so fast. You have to admit though there has been a slew of old posts and one line questions lately for some reason.
And that’s probably just a coincidence. I’ve never owned a vehicle that matched all the time. I keep meticulous records, and most of the time they don’t match. Every once in a while they do.
[quote=“MikeInNH, post:39, topic:77854”]
I’ve never owned a vehicle that matched all the time. I keep meticulous records, and most of the time they don’t match. [/quote]
If a driver burns 100% ethanol-free gasoline(E0), the car computer is more likely to be more accurate to paper & pencil MPG calculations. In my cases, 87 octane E0 car computer outputs give more accurate MPG readings compared to paper & pencil, than 87 octane 10% ethanol blend car computer outputs.
Yikes. Prices jumped significantly here overnight but it went up to $2.55 for E10.