3 ms·

> No, ethanol has a lower energy density, but not that much lower as to make a huge difference. This isn't correct. It does make a huge difference in 4-stroke

> No, ethanol has a lower energy density, but not that much lower as to make a huge difference. This isn't correct. It does make a huge difference in 4-stroke and an even larger difference in 2-stroke. Any engines that are being used for capacity / load will showcase the differential in a very significant way. Even according to the US Department of Energy they state that: "Denatured ethanol (98% ethanol) contains about 30% less energy than gasoline per gallon." [0] If you've never towed in a vehicle that can use E-10 or E-15 and compared, I'd suggest you give it a shot. Be prepared for upwards of over 25% difference in gas mileage alone, not to mention reduction of power. [0] https://afdc.energy.gov/fuels/ethanol_fuel_basics.html https://afdc.energy.gov/fuels/ethanol_fuel_basics.html

credit_guy 3y ago
Well, as someone else replied in the thread, if pure ethanol (98% is basically pure) has 30% less energy density than gasoline, then a mix of 90% gasoline and 10% ethanol has 3% less energy density. I'm not sure what you mean by E-10. Basically all gasoline that is sold in the US is E-10. You have to look hard to not get E-10. I doubt you have performed the experiment you described, for the simple reason that it's hard to find gasoline that's not mixed with ethanol. I just googled, and apparently gasoline without ethanol is called "recreational gasoline", or REC-90 [1]. [1] https://en.wikipedia.org/wiki/REC-90 https://en.wikipedia.org/wiki/REC-90
- windexh8er 3y ago
  > I'm not sure what you mean by E-10. Basically all gasoline that is sold in the US is E-10. You have to look hard to not get E-10. I doubt you have performed the experiment you described, for the simple reason that it's hard to find gasoline that's not mixed with ethanol. It's not really productive to make assumptions. Where I live I can buy non-oxygenated gas at almost every station. And, yes, I actually do this experiment all the time given I'll drive to places with a trailer where I'm forced to run an ethanol blend. I realize my comment conflated two things: the reduction of performance and the difference in power per straight gallon. My point is that even with a minimal blend you can lose significant mileage / power. The easiest layman's way to measure that is in MPG. And, yes, there is a significant drop in both power available and MPG. And for reference [0]: "Due to ethanol's lower energy content, FFVs operating on E85 get roughly 15% to 27% fewer miles per gallon than when operating on regular gasoline, depending on the ethanol content. Regular gasoline typically contains about 10% ethanol." The above is in normal driving. So, no, I'm not making my statement up. [0] https://www.fueleconomy.gov/feg/ethanol.shtml https://www.fueleconomy.gov/feg/ethanol.shtml
- jerrysievert 3y ago
  it's called "clear" gas around here. there's a website that tracks places to buy it in all 50 states: https://www.pure-gas.org https://www.pure-gas.org - but I've noticed that it doesn't track every location and is often wrong about prices, at least in my area. I've never seen "REC-90" and had never heard of it before your posting. clear gas in my area is 92 octane, with up to 110 available in select locations. most everyone I know who drives a performance vehicle, or a motorcycle can tell you where their closest gas station that sells clear gas is. > I doubt you have performed the experiment you described, for the simple reason that it's hard to find gasoline that's not mixed with ethanol. I've performed it many times over the last 17 years I've owned my current car. the results are always the same: 25% better gas mileage with the clear gas. I keep track of my mpg, and am able to quickly see any difference between gasoline grades. I typically drive in my car's "power band", staying between 5000 and 6700 RPM.
- smolder 3y ago
  IME, the gas stations that sell ethanol-free gasoline seem to exist around farms or places where people use off-road gas powered equipment, though I don't have many data points. It stores for longer than ethanol blends (which absorb water over time), so it's better for filling up gas cans used to fill equipment, or infrequently used vehicles.
  - bombcar 3y ago
    Around here every station has non-oxy premium but only one station has ethanol free regular unleaded 87.
  - forgetfreeman 3y ago
    Ethanol also has a nasty tendency to eat various portions of the fuel systems in older vehicles that don't have gaskets and hoses made of material specifically formulated to withstand it.
- zdragnar 3y ago
  REC-90 is a very specific blend, which isn't sold in many states for the simple reason that they have others available. Hell, just read the first sentence of the second paragraph of that wikipedia page: > Unlike most stations in the plains states which carry ethanol-free 87 octane unleaded alongside 10% ethanol 87 octane unleaded, ... As a midwest resident of a non-plains-state, I can confirm that there are plenty of gas stations that sell no-ethanol gas, either 87 or 93 octane (usually the higher, since it's a premium product anyway).
ac29 3y ago
If roughly pure ethanol has has 30% less energy than gasoline, going from a blend of 90/10 gasoline/ethanol to a 85/15 blend shouldn't decrease mileage by 25%.
- windexh8er 3y ago
  It does [0]. "Due to ethanol's lower energy content, FFVs operating on E85 get roughly 15% to 27% fewer miles per gallon than when operating on regular gasoline, depending on the ethanol content. Regular gasoline typically contains about 10% ethanol." [0] https://www.fueleconomy.gov/feg/ethanol.shtml https://www.fueleconomy.gov/feg/ethanol.shtml
  - joshyeager 3y ago
    That link is about E-85. E-85 is 85% ethanol (actually 60%-85% depending on the season and the gas station). Ethanol has 30% less energy density than pure gasoline, so E-85 has 0.3*0.85=0.255 less energy density than pure gasoline. That is why E-85 gets 25% lower gas mileage. "Standard" E-10 gasoline contains between 0% and 10% ethanol. E-15 is 15% ethanol. So E-15 has at most 4.5% less energy density than standard gasoline. You would not see a 25% decrease in gas mileage between standard gas and E-15.

credit_guy 3y ago

Well, as someone else replied in the thread, if pure ethanol (98% is basically pure) has 30% less energy density than gasoline, then a mix of 90% gasoline and 10% ethanol has 3% less energy density. I'm not sure what you mean by E-10. Basically all gasoline that is sold in the US is E-10. You have to look hard to not get E-10. I doubt you have performed the experiment you described, for the simple reason that it's hard to find gasoline that's not mixed with ethanol. I just googled, and apparently gasoline without ethanol is called "recreational gasoline", or REC-90 [1]. [1] https://en.wikipedia.org/wiki/REC-90 https://en.wikipedia.org/wiki/REC-90

windexh8er 3y ago
> I'm not sure what you mean by E-10. Basically all gasoline that is sold in the US is E-10. You have to look hard to not get E-10. I doubt you have performed the experiment you described, for the simple reason that it's hard to find gasoline that's not mixed with ethanol. It's not really productive to make assumptions. Where I live I can buy non-oxygenated gas at almost every station. And, yes, I actually do this experiment all the time given I'll drive to places with a trailer where I'm forced to run an ethanol blend. I realize my comment conflated two things: the reduction of performance and the difference in power per straight gallon. My point is that even with a minimal blend you can lose significant mileage / power. The easiest layman's way to measure that is in MPG. And, yes, there is a significant drop in both power available and MPG. And for reference [0]: "Due to ethanol's lower energy content, FFVs operating on E85 get roughly 15% to 27% fewer miles per gallon than when operating on regular gasoline, depending on the ethanol content. Regular gasoline typically contains about 10% ethanol." The above is in normal driving. So, no, I'm not making my statement up. [0] https://www.fueleconomy.gov/feg/ethanol.shtml https://www.fueleconomy.gov/feg/ethanol.shtml
jerrysievert 3y ago
it's called "clear" gas around here. there's a website that tracks places to buy it in all 50 states: https://www.pure-gas.org https://www.pure-gas.org - but I've noticed that it doesn't track every location and is often wrong about prices, at least in my area. I've never seen "REC-90" and had never heard of it before your posting. clear gas in my area is 92 octane, with up to 110 available in select locations. most everyone I know who drives a performance vehicle, or a motorcycle can tell you where their closest gas station that sells clear gas is. > I doubt you have performed the experiment you described, for the simple reason that it's hard to find gasoline that's not mixed with ethanol. I've performed it many times over the last 17 years I've owned my current car. the results are always the same: 25% better gas mileage with the clear gas. I keep track of my mpg, and am able to quickly see any difference between gasoline grades. I typically drive in my car's "power band", staying between 5000 and 6700 RPM.
smolder 3y ago
IME, the gas stations that sell ethanol-free gasoline seem to exist around farms or places where people use off-road gas powered equipment, though I don't have many data points. It stores for longer than ethanol blends (which absorb water over time), so it's better for filling up gas cans used to fill equipment, or infrequently used vehicles.
- bombcar 3y ago
  Around here every station has non-oxy premium but only one station has ethanol free regular unleaded 87.
- forgetfreeman 3y ago
  Ethanol also has a nasty tendency to eat various portions of the fuel systems in older vehicles that don't have gaskets and hoses made of material specifically formulated to withstand it.
zdragnar 3y ago
REC-90 is a very specific blend, which isn't sold in many states for the simple reason that they have others available. Hell, just read the first sentence of the second paragraph of that wikipedia page: > Unlike most stations in the plains states which carry ethanol-free 87 octane unleaded alongside 10% ethanol 87 octane unleaded, ... As a midwest resident of a non-plains-state, I can confirm that there are plenty of gas stations that sell no-ethanol gas, either 87 or 93 octane (usually the higher, since it's a premium product anyway).

ac29 3y ago

If roughly pure ethanol has has 30% less energy than gasoline, going from a blend of 90/10 gasoline/ethanol to a 85/15 blend shouldn't decrease mileage by 25%.

windexh8er 3y ago
It does [0]. "Due to ethanol's lower energy content, FFVs operating on E85 get roughly 15% to 27% fewer miles per gallon than when operating on regular gasoline, depending on the ethanol content. Regular gasoline typically contains about 10% ethanol." [0] https://www.fueleconomy.gov/feg/ethanol.shtml https://www.fueleconomy.gov/feg/ethanol.shtml
- joshyeager 3y ago
  That link is about E-85. E-85 is 85% ethanol (actually 60%-85% depending on the season and the gas station). Ethanol has 30% less energy density than pure gasoline, so E-85 has 0.3*0.85=0.255 less energy density than pure gasoline. That is why E-85 gets 25% lower gas mileage. "Standard" E-10 gasoline contains between 0% and 10% ethanol. E-15 is 15% ethanol. So E-15 has at most 4.5% less energy density than standard gasoline. You would not see a 25% decrease in gas mileage between standard gas and E-15.