MPG with different fuels

Actually, both MTBE and then ethanol were chosen for BOTH their oxygenate and anti-knock properties. Here is at least one link for an explanation... Why is there ethanol in gasoline?

 

While MTBE and ethanol are used for both their anti-knock and oxygenate properties, I don't believe either is essential to produce adequate octane ratings in the post-lead era.

Cars have required unleaded fuel since at least model year 1975 (I had thought 1973, but don't see it online), but MTBE didn't start entering the fuel supply until 1979. While I believe at least one area fuel brand was using ethanol a long time ago -- I recall Arco settling a state lawsuit in the early 1980s for not labeling it on the pump -- the others were not. Other compounds were used to achieve the needed octane ratings, though possibly at higher cost.

The federal oxygenate mandate, for certain air pollution non-attainment areas in certain seasons, started in 1992. I haven't yet found when oxygenates started expanding to whole states year-round. I don't know about MTBE locally, but ethanol was absent from most fuel until one of those federal mandates appeared. It caused considerable problems initially as years worth of water collected at the bottoms of underground fuel tanks was soaked up all at once, and fuel line parts in some older cars were attacked.

Ethanol also fits into renewable fuels mandates, so it seems to kill three birds with one stone. Maybe more, if the various political lobbies are counted.

 

National Renewable Energy Laboratory (NREL) Home Page
NREL: Overview

 

This is my first time speaking out about this subject. I do not have a hybrid, but I have a pretty fuel efficient car. I have a 2007 Hyundai accent and according to the E.P.A. I am soppose to get 28/37 mprg. I looked it up and I was wondering why I average 26 mpg, and why it got worse on the open road. I put in a low viscosity full synthetic oil. I also changed the spark plugs to irridium laser series. I changed the tires to new ones and good brand. I gave it a fuel treatment. All that and I still got a bad number on my mpg. It finaly hit me yesterday. Most gas stations have gas mixed with 10%ethanol. That is why I do not get the mpg I should be getting. I looked on pure gas.org and saw there is 2 gas stations I can go to near me that have 100% gas. I will admit that it is expensive; $4.69 as compared to $3.67 but the mpg I am getting is horrible. I am hypothesizing that because gas mixed with 10% robs me of 15% power I do have the power it takes my car to achieve my cruising speed. My cruising speed right now is 40 mph at 1500 rpms with my car on overdrive. Any more mph after that is not as efficient. I put in a full tank of 100% gas today and I drove it a few mile to get the fuel line pumping the 100% gas. I did notice that I was not needing to press the gas pedal down as much to climb the bridge near my home. I even reacted by telling my wife, who was next to me, "What the...... damn I'm accelerating up the bridge and I didn't even press down on the pedal more than I ussualy do. Letssee what happens. I for one did notice the difference. On another not, I don't think it should be up to the government to decide to make it difficult to have good mpg. Plus, I don't remember voting to have the massive change from pure gas to 90/10. If I am getting a worse mpg ratio, then I am lining the pockets of the oil companies. By the way, that guy that was talking bad about Dig4dirt, U suck. I always remember what my mother told me when I was a kid. The sheet of paper will hold anything u write on it. In other words don't beleave everything that the gas companies say. For one, I noteced the difference between the two types of gas. Pure is better. Would u like your blood oxygen level to be 90% or 100%. No u would not. Same goes for gas efficiency. It makes a hell of a difference.

 

I stick with top tier gas as it yields the best mpg: 52 - 54.

DBCassidy

 

Per Compare Side-by-Side, the 28/37 was adjusted to 24/33, 28 mpg combined since the model year 2008+ EPA method had changed. No, the EPA estimates are NOT supposed to be expected gas mileage. If you believe it is, please point me to a site with the .gov domain that states it is.

Please read Car and Driver: The Truth About EPA City / Highway MPG Estimates | PriusChat to learn more about the EPA test. You also might find Car and Driver: Here’s Why Your Mileage May Vary (A Lot) from the EPA Estimates | PriusChat insightful.

Besides the fact that the EPA test isn't on a real road, but rather a dyno and doesn't measure actual fuel usage, they also use a special blend of fuel.

 

You may need to decide if your goal is higher MPG or using less gas. Driving out of your way to get E0 will almost assuredly mean you are using more petroleum than buying on your normal route.

No Prius has shown better MPG with higher octane fuel. But there is always a chance that some new engine will, the Prius C engine is quite changed from the Gen 2.

 

ok so getting 26 mpg on $3.67 gas (14.2 cents per mile) and unhappy so want to use $4.69 gas (which means you have to average 33 MPG to BREAK EVEN)

i would rethink that if I were you

 

Almost certainly not. E10 might drop your MPG by 3.3%, it can not drop it by 10-15% as that would mean that somehow the ethanol was leaching energy out of the gasoline.

You should pay no more than $3.79 for pure gasoline if, as seems likely, it is reducing your mileage by 3.3%
You should pay no more than $4.04 for pure gasoline if it is reducing your mileage by the 10% you claim.
At $4.69 you are being robbed.

I am glad you brought this up so we can make sure nobody gets drawn in by these oil companies.

 

Right, I haven't made a habit of it and have only done it a few times to experiment. The lower octane stuff at this one pump is NOT ethanol-free, so one is forced to buy high-octane to get ethanol-free. It's also a dollar more than the regular unleaded ethanol blends that are local to me last I checked.