Best gas -- premium? Ethanol free?

I just filled up our tank a couple of days ago with pure regular gas 0% Ethanol in Shelton, Wash. Was only $3.94 / gal. and
regular 10% Ethanol was $3.74 per gallon. I had one pip left and it took 8.9 gallons. I noticed
an immediate improvement of at least 2-3 mpg more than reg. e10. Currently with nearly 300 miles on this tank the computer gauge is reading over 63 mpg while normally it would read 55-58 mpg.

I understand that you should loose only 1.5-3% efficency with 10% ethanol gas over 0% ethanol gas, but it does not seem to hold much water in my case.

I wonder if many people know that the EPA fuel economy test are conducted with 0% Ethanol, not 10% Ethanol where 99% of the driving population is required to use or can conviently buy.

You would think, that the government would use a controlled sample of regular 10% ethanol and premium 10% ethanol to conduct those test. Why use a fuel that only 1-5% of the driving population has access to????

The only obvious answer, is that they should but they don't.

Of all people even VP Al Gore later admitted that Ethanol in fuels is not a winning argument.....

 

Sure it does.
If you are getting about 60 MPG, 3% of that is 1.8......which is pretty close to 2.....and well within the "measurement error".

And I wonder how many people know that the final EPA number is created with a "prototype" vehicle in most cases, which never sees a real road and is determined by math more than actual road tests ??
Not many it seems.

 

Holy CRAP!

I just filled up yesterday at a big box place.
$3.06

I'll keep using the cheap stuff....thanks just the same.
I don't pay for the gas in my company car (the G3) and the closest gas station to the office is a grungy Mom and Pop place that claims to have "real gas." I tried a few tanks and didn't see much of a difference. I guess that's what they mean by YMMV.

I've read all of the FUD with ethanol including how it's killing motors, rusting gas tanks, killing the planet, and causing world hunger.
With all due "respect" to the former VP, the only things that I've put together in my head over the whole modern automotive temperance movement is that most gas tanks are made out of plastic, you can't grow corn in the Middle East, and obesity is one of the leading causes of health problems in kids today.
I don't drink much corn whiskey, and I don't mind eating grass-fed beef.
Burning corn as fuel is probably one of the least stupid things we do with the stuff, and we've never sent a Carrier Battle Group into the NAG to bomb and kill people......over corn.
My 401(k)is probably as muddled ay anybody else's but AFAIK I'm no more fiscally subservient to Big Corn than I am to Big Oil.

Toyota says my car can burn up to 10-percent of the stuff, so I think I'll keep the give-a-crap switch in the "don't" position until and unless I'm swayed by light rather than heat in this matter.

Your Mileage May Vary.

 

You could be seeing a "double-whammy" due to higher energy content in the gasoline portion of the E0 (in theory up to almost 7% more). With ethanol, that could explain MPG variations as much as 3+7 = 10% or 5 MPG on Prius.

Therefore any differences you are seeing are not necessarily all due to the ethanol. Energy content of gasoline is allowed to vary, and its not necessarily predictable, but you could see a dependable trend at your stations.

...believe the way the "pros" (EPA/industry) handle this during MPG testing is that they measure energy content of the gasoline and then use correction factors to adjust the observed MPG readings to a constant energy content. This is the step you are missing, and this is how they get away without using E10.

However, bottom line, as you state, as cars start getting better MPG like Prius more consumers will start to ask if it makes sense to intentionally take energy out of gasoline as per ethanol and also RFG is lower energy.

 

Yes my driving Is pretty consistant. Almost all in town with lots of short trips. That is why it takes about 5-6 weeks to use a tank. I like the mpg.

 

My last tank was at $2.979

CAFE gas mileage test procedures have been the same since 1975, if you change the fuel, all those tests are wrong. They are already dictated out to 2025, if you change the fuel, all those test are wrong. There was no ethanol in use in 1975.

http://vault.sierraclub.org/transportation/downloads/2011-07-Truth-in-Testing-Report.pdf

 

Just to chime in my results with E10 and E0.

Best tank:
E10 51.5 mpg
E0 57.6 mpg

These results are with driving my normal daily commute with the same driveing habbits and air temperatures between 85 and 95 degrees farenhiet.

I gained roughly 11.8% between the two tanks.

 

...OK I might believe you... I've been trying to say, this approx. range of MPG variation is possible, based on energy content variations in the gasoline (hydrocarbon) portion

 

I'm currently trying to only use no ethanol gas so that I could get a good average to compare to my average on E10 gas. I saw an 11.8% increase in my max mpg on both while most people state that a 3% increase is all you would see due to e10 having 3% less free energy. This is true but there are other factors people seem to neglect, for example ethanol has a significantly higher flash point than gasoline. This makes it more difficult to vaporize ethanol at any given temperature compared to gasoline. These fuels need to be vaporized in order to ignite. Therefore it stands to reason that alot of the ethanol may not be burning.

 

I agree totally except it would be unexpected for Prius to show >3% MPG loss due to E10 ethanol alone. However, we do not have official EPA MPG studies on E10 vs. E0 impact on Prius MPG or any car, so we are reduced to conjecture. My conjecture is that it's not just the ethanol contribution, but also the hydrocarbon portion can vary on energy content up to +-7%. You are saying you think maybe the ethanol itself can be more than 3% MPG debit. I agree that is possible, since we do not have official E10 vs. E0 MPG testing by EPA or Consumer Reports or anyone else.

Under the circumstances, we are accepting any hypothesis pending the truth, or just give us E0 as an cost-effective option for all.

 

You are not right about the octane rating of gasoline relating to the speed of combustion. Octane is how much pressure (the Air/fuel mixture heats up during the compression stroke from cylinder temps and the actual process of compression) the fuel can withstand before self ignition. In the case of ICE's, heat and pressure are proportionate. Once the compression reaches the air/fuel mixture's ignition point, you have pre-ignition. The lower the octane, the less pressures, aka heat, it can handle. What ends up happening is, the computer increases fuel trims to cool the combustion chambers down due to no EGR or exhaust cam VVT and increasing intake cam duration to affect compression pressures (aka Atkinson cycle), and then ignition timing is retarded until the ECM determines the knock signal is satisfactory. The higher the octane, the more pressure the cylinder can handle, less fuel is needed to achieve the same power output, the hotter the combustion is, and ultimately the highest volumetric efficiency is obtained by Natural Aspiration. This is true and proven for all common engine types, only current ignition systems are all electronic and self adjusting vs. older distributor style ignitions. Also, the higher compression ratio that the 1NZ-FXE is capable of could, if the programming was designed for it, benefit from higher octane. The the higher cylinder pressures on compression are negated by combustion on the opposite TDC cylinder while it's running. Yes it's harder to turn at first before combustion first takes place, but afterwards it not much harder than lower CR engines. (That last part is theoretical by top engine builders). I've been threatening trying this theory out on current model prii that have parameters for individual cylinder crank speeds. Graphing the speeds out while adjusting the cam actuator for higher CR's and then lower CR's and comparing graphs. Or, by saving a graph before and after cam swaps with, say, a yaris (or corolla for the genIII prii).

Wow, my mind got away from me there. Sorry to ramble.