The reason I posted the sentence in that manner is purely because I have no means of knowing the ethenol content from any station. All of them have the ethenol labels on the pumps.
Knowing that ethenol content effects mpg it seems the answer to the conundrum, but at just one station ? ( out of three. ) I do not get gas from all of the eight stations between home and work so my investigation is not scientific.
but…
Hey folks,
Took a family trip and it afforded me the chance to compare eth-free vs. E-10 for mpg. Filled up with eth-free at home, drove to our destination. Filled up with E-10 when we arrived at our destination. We stayed in one spot when we arrived so the comparison of the fuels was over the exact same route, exact same number of miles.
Trip was 430 miles each direction. Change in elevation was under 600 feet over the entire span of the 430 miles. We live at 600’ elevation and traveled to sea level, then back. One little bluff we drove over, but it’s basically a ridge that butts straight up from the ground and it’s roughly a 5-mile uphill climb coming at it from either of the directions we traveled. Other than that, it’s a pretty flat drive. No significant difference in weather over the span of our entire trip. It was a clear and beautiful week, nothing more than a light breeze. Basically gorgeous weather all that week.
The drive was nearly an exact split of Interstate and 55 mph highway travel (roughly 215 miles on each). Left the cruise on 75 mph on Interstate and 60 on the smaller highway. Both ways we had almost no traffic so about the only time I had to pop it off cruise was when pulling over so we could relieve ourselves, or “exit our water” as one of my South American friends used to say.
Here are the results I got:
Eth-free outbound trip netted 17.96 mpg or 18 mpg.
E-10 return trip netted 14.72 mpg.
22% higher mpg with ethanol-free than with E-10.
It’s hard for me to pin anything on my Burb not running as it should. It’s a 1996 4x4 with 185,000 miles on it and it cranked out 18 mpg over a span of 430 miles, carrying five passengers with all of our crap filling up the cargo area behind the seats (which is no small space). It seems to me that my Burb is running as efficiently as it was designed to be capable of.
At least with our Burb, I can find no reason for running E-10 and I can find no basis for how in the world it could be better for the environment or our family’s wallet for us to get 22% less mpg by running E-10. As far as I’m concerned, the jury’s in on this one. E-10 is OUT.
Someone asked if my Burb is a Flex-fuel vehicle. No, it’s not. It’s a '96.
I bought a new BMW k75 motorcycle in 1994. Watercooled 3 cylinder, basically a small car engine. !8 years of riding the same 29 mile route to work each way about 80 to 100 days a year gives me a consistent basis for comparison. With 10% ethanol mileage is always 50 mpg +or minus 1 mpg. With pure gas it’s 53 + or - 1. Comparing the increased mileage with the increased cost it comes out a wash. I stick with the premium because of reports that some rubber parts in the fuel system degrade over time.
Hey Kriley,
Thanks for the input about your bike.
It seems to me that E-10 is a fit for some motors and not a fit for others. Thanks to my ignorance, I don’t know the why behind it, but perhaps it has something to do with how it alters the ignition point in relation to top dead center, as someone mentioned in this thread. Seems logical enough to me. If you’re retarding or advancing your ignition point, the motor runs out of spec. Perhaps newer motors are micro-managed by computers enough that this can be compensated for or adjusted to essentially erase the change and put the motor back into spec without the driver ever noting much of a difference between fuels.
I could easily see BMW’s equipment being advanced enough in '94 to already accommodate the difference in fuels. But that’s just a hunch.
I’m enjoying learning from everyone.
I’ll toss my nickel into the mess. On a pure energy basis ethanol has about 66% of the energy content of gasoline (1.0 US gallon of ethanol has 76,100 BTUs, compared to 114,100 BTUs for gasoline). With a 10% ethanol mix you have 110,300 BTUs or about 96.5% of the energy of pure gasoline. So we can expect a 3.5% drop in fuel mileage from an energy standpoint. BUT, ethanol has different burn characteristics than gasoline, and if the engine can take advantage of them you may not see a drop or might even see a slight increase in fuel mileage. The people I’ve talk too who have seen a decrease in fuel economy have a carburetor or a fuel injected engine that doesn’t take advantage of properties of ethanol.
I’ve read the posts here is it seem that the people seeing a decrease are in older cars 12+ years old, which kind of fits my theory that older cars can’t make the adjustments needed to take advantage of ethanol. I am also thinking that people may feel less power and accelerate harder to make it for it making their fuel mileage even worse.
Hey rwee2000. I think your comments make sense. If I was running a newer vehicle, I’d run E-10 without reservations. My 96 just doesn’t care a whole lot for it.
@Burb Bum:
I liked the “experiment” you set up with the out-n-back road trip. Very methodical; seems you left everything else constant, and just changed one variable. Except…
…for the direction of travel. Most of the “lower 48” US has prevailing Westerly winds. If the outbound trip was with the wind (i.e. headed East) it could be a possible explanation for the observed data.
ONE trip…it’s IMPOSSIBLE to get an accurate account of the gas mileage. You really need several trips with each and then take the average.
For years I developed accurate line graphs for 3 of my vehicles using 10% ethanol blends. Then, I switched to 100% gasoline(ethanol free) & have accurate years long records to compare with my years of 10% ethanol blend usage. My three vehicles, after switching to 100% gasoline, gave 8%, 7% & 5% better mpg. All engines run quieter, smoother & with a bit extra low rpm torque, such that less shifting down to ascend hills & mountains is needed.
Gasoline engines have been designed & built to use 100% gasoline(the EPA rates gasoline cars for mpg using the equivalent of 100% gasoline & manufacturers like their choice of 100% gasoline). Ethanol needs higher compression ethanol engines to get its efficiency. Ethanol is a foreign burning product in engines built & designed to get their most efficiency with 100% gasoline.
This is not rocket science. But it is good 100% gasoline(ethanol free) science, that gasoline engines get their best efficiency(above & beyond energy considerations) using 100% gasoline.
If you want to see cornflakes and bourbon drop in price-tell your congress person to kill the ethanol mandate.
Update to previous post:
Since the accurate decade of records for my previous 3 vehicles, showing obvious increases of 8%, 7%, & 5% in mpg using 100% gasoline(ethanol-free), as opposed to 10% ethanol blends, I have a new 2013 Hyundai Elantra(Epsilon Lyrae), bad-mouthed by many lead footed drivers for poor mpg. Not pussyfooting around using despicable 10% ethanol blends, but excellent 100% gasoline, Epsilon Lyrae is presently averaging 39+mpg, with 15% city driving & fuel in tanks, used up in 3 to 7+ day periods. No tank was used within hours of highway driving without multiple cool downs. The last 6 out of 8 tanks have been 40mpg or more. As reported for my previous cars, the Elantra engine is smooth & quiet, with OK low rpm torque(altho Elantra doesn’t have good torque, at all).
Since the Anacortes, WA oil refinery fire, the price gap between 100% gasoline & 10% ethanol blends, here in the Pacific Northwest has increased between 7% to almost 10%. However, the quality of 100% gasoline, causes Elantra to run as it was designed to operate, & not crippled trying unsuccessfully to digest ethanol. The range of Epsilon Lyrae, using 100% gasoline, is like an extra gallon of gasoline is in the tank, without having to install a new tank or carry an extra gallon of gas!