Is there indeed a "Free Lunch"?

I fail to see any reason why you would see an increase in fuel efficiency with premium.

 

F8L, he may be at as station where Regular is E10, so gets 3% less MPG, while Premium is E0 at that station, so gets 3% more MPG. I never see Premium only 3% higher than Regular, but that is the only explanation I can think of.

If they are the same percent Ethanol, he sure won't get any better mileage with Premium.

(It is remotely possible he is ignoring all the warnings and using E85 in his Prius. Until it breaks, he would get 25% worse mileage on E85, but that is self correcting because he will need a new engine, and will pay closer attention after his out of warranty $3000 bill)

 

How do you know he will need a new engine if he runs E85? What's gonna break? How do you know a new engine costs $3000? Have you ever ran E85? How do you calculate the 25% worse mileage? My '04 V6 Saturn Vue AWD runs excellent on E85. It gets 19.xx city & 24.xx on the Interstates running 70 mph every week for the past 20k miles. Someone can look up the spec's on what it gets on 87 octane. There is no way it is getting 25% worse gas mileage running straight E85. This is a 10:1 CR Honda motor.

Wasn't there some people a while back that posted their Prius got higher mpg's on 89 octane verses 87 octane? Could it be the 13:1 CR? Interesting stuff

Mike

 

Toyota specifically warns you NOT to use over E10 in the Prius. None the less, folks have tried.

en.wikipedia.org/wiki/Ethanol#As_a_fuel
(34.8 - 25.2) / 34.8 = 27.6% less energy per volume

No, I have not, I read the owners manual when I bought the car, and am not an idiot.
The nearest E85 to me is 30 miles away in Webb, MS and is priced at $3.25 which is more money than 25% lower than E0 or E10, so I would lose money. (and sadly not a brand my wife's employer will pay for. Her company car is FlexFuel ready for E85)

Bob Wilson, whom I trust, did extensive tests with different grades of gasoline looking for performance differences.

 

You are very likely wrong.

however, the person you need to convince is yourself - since you are the one spending the extra money for premium.

You might want to consider doing the following:

01) identify and record the gas station you are using (name, street address) for the first fillup
02) identify and record the brand of Premium grade, octane rating, and percentage of ethanol that is in your fuel that you have selected.
03) do a complete fillup ( stop pumping at the first click)
and then record/identify the exact price you paid for your fuel per gallon
and how many gallons you purchased
04) the record/identify date when you purchased your fuel
05) record/identify distance you cover with this first tank of gas in miles - it should be atleast 580 miles
06) use the same exact gas station you are using (name, street address) for the second fillup
as you did for the first fillup
07) identify/record the brand of regular grade, octane rating, and percentage of ethanol that is in your fuel that you have selected for the second fillup.
08) do a complete fillup ( stop pumping at the first click)
and identify/record the exact price you paid for your fuel per gallon
and how many gallons you purchased
09) the date when you purchased your fuel
10) you need to report distance you cover with this second tank of gas in miles - it should be atleast 580 miles
11) identify/report the date when the next fill up was and how many gallons did you need to do the next fillup.
12) compute/report the difference in MPG between the two tanks

 

I agree anything more than E10 is risky proposition.
It is wiser not to tempt the fates.

I saw a video on these new types of ethanol blend gasoline pumps which allow the buyer to vary the percentage of ethanol in the gasoline to his/her liking. Such a thing does not exist in the Washington DC area but the video I saw indicates they exist in the midwest. Recently, the corn ethanol lobby was been lobbying the federal government to change the fuel standard mandate for metro areas from 10% ethanol to 15% ethanol gas.

 

This is why when the EPA conducts testing for fuel economy the
standard fuel for gasoline engines should be 10% Ethanol blend for
regular and premium grade gas.

Currently the EPA uses pure gasoline with NO Ethanol.
Yes the EPA which forced the use of Ethanol down our
throats will not even conduct their testing with it....

 

what do the manufacturers use when they test? Many cars are never tested by the EPA.