MPG with different fuels

Pure gas has 3.3% more energy than E-10. If you are seeing a different number, you are seeing something other than that. Two tankfuls just isn't a valid statistical sample for determining exactly changes in mileage.

Go ahead and buy pure gas if it is no more than 3.3% more expensive, otherwise don't.

^^ and a driver who gets an 18-23% mpg improvement after adding a partial tank of pure gas, producing a mixture that is still one-third to one-half E10, is most certainly seeing something other than that.

I have owned a 2010 Prius as well as the old 2002 Gen I. I have always hated driving behind a Buick because 90% of the time the driver always accelerates and drives so slow...............I will never own a Buick because I don't want to be labeled as slow...................Personally, I see no need for slow acceleration. Accelerate briskly to your desired speed and keep it there. When you pull away from a light, there are usually dozens of drivers who want to make that light --not just you. My lifetime overall MPG for the 2002 Prius was just over 44. The 2010 was 49.5 MPG. My motto for accelerating from a stop light is "get your A** in gear".

Go to pure-gas.org to find addresses, details, & a great zoomable map to the 5400+ stations that sell 100% pure gasoline. With accurate records(with great generated line graphs), switching to 100% pure(ethanol-free) gasoline caused our 3 cars' mpg to increase 8.5%, 7-8%, & 5%. All engines run smoother, quieter, & with more power, such that, less downshifting is needed to ascend hills.

For efficiency, ethanol needs ethanol engines with much higher compression ratios than gasoline designed engines have. That is why most people who compare 100% gasoline & 10% ethanol blends carefully, have much better 100% pure gasoline mpg than the btu differences (3%) between 100% pure gasoline & 10% ethanol blends.

litesong,

Your oft repeated song has only one note. Do you ever post anything except pure-gas.org spam?

Posting it 100,000 times on a 1000 different forums does not make it true.


Tom

Glad to hear that you have read more than one of my posts.

The ethanol industry pays the fed gov't & controls the erroneous talk on blending ethanol into our 100% pure gasoline supplies. We can hear your siren song for the ethanol industry. I am here to say the ethanol industry lies, saying the power drop from ethanol use in gasoline engines is only 2%-4% because of btu loss. Ethanol also needs higher compression ratio ethanol engines to get its efficiency, as compared to lower compression ratio gasoline engines . Thus, the difference between 10% ethanol blends & 100% pure gasoline is much greater than 2%-4%. My post above tells of my happy increases in mpg by switching to 100% pure gasoline over the last 10 months as compared to years of 10% ethanol blend use.

You should accurately keep records of your use of 100% pure gasoline & be happy like me.

It is impossible to avoid you! A Google search of litesong and ethanol generates over 65,000 hits. Your single minded, misguided, anti-ethanol crusade is only admirable for its passion. Your passion does not outweigh your ignorance and bad advice. Your anti-ethanol arguments have been successfully countered hundreds of times here and on other sites, yet you will not listen. Fine. Believe what you wish.

On the other hand, your continued pimping of pure-gas.org is reprehensible. That website recommends too many no-name vendors pumping random unbranded gasoline. Even worse, the site recommends marinas and airports! Marine fuel is not formulated for automobiles. Aviation fuel still contains tetraethyl lead. This user comment about Air West Flight Center's 85 octane fuel says it all; 'It should be noted that you have to have a separate container to fill up here. They don't charge "road use tax" so they can't put it directly in your car.' Sure. When a seller is breaking the law in the first place, he won't worry about road use tax.

Pure-gas.org pushes fuels that worsen the air pollution that put oxygenates into gasoline in the first place - junk gasoline that will ruin my new Prius. I for one will not replace top tier E10 with junk. If you really want to help your cause, stop your barking and clean up that website. It's disgraceful.


Tom

Google searches have a lot of cross-referencing......... a mighty lot!

pure-gas.org tells people where 1oo% gasoline can be found because the ethanol industry continues to add ethanol to gasoline supplies for engines designed to run best on 100% pure gasoline. pure-gas.org makes no recommendations, except to use 100% pure gasoline.

Top tier 10% ethanol fuels can't be top tier if 100% pure gasoline delivers 5 to 9% better mpg.... which shows that top tier gasoline & ethanol advertising delivers more money into the hands of oil companies & the ethanol industry.

You must be an ethanol industry junkee. Ethanol is considered to be an oxygenate. Why do YOU push ethanol, when gasoline designed engines do best on 100% pure gasoline.

From a pollution point of view, you must oppose the increasing number of diesel cars that barely make the pollution standards of the U.S., instead of chasing after 100% pure gasoline.

In other words you are completely behind pure-gas.org? Fair enough. It's good that you stick by your friends. However, that site brands itself as "the definitive list of stations that sell ethanol-free gasoline" with 5000+ recommended stations, most of which sell unbranded fuel (or worse). Help yourself.

With respect to your often asserted claim of increased mileage, let's quote your favorite website, pure-gas.org (paragraph 12) "The free energy of gasoline is 34.2 MJ per liter. The free energy of ethanol is 24 MJ per liter. That means E10 (10% ethanol) has a free energy of 33.2 MJ per liter, and E85 (85% ethanol) has a free energy of 25.6 MJ per liter. As a result, your mileage is reduced by 3% with E10 over ethanol-free gas." How often have you heard that? But if you wish to cut your friends loose over this issue, I'm sure you can have your mileage data audited for accuracy, including odometer records, purchase receipts, automobile maintenance records, gasoline analysis test results, and driver training and techniques to control experimental bias.

Until then, posting it 65,002* 18,502 times on a 1000 different forums does not make it true.


Tom

*cwerdna, per the post below, is right. 65,000 goes to 18,500. Either way that's a lot of forum spamming.

Heh. Some of the Google hits are wrong. Some of them have the word lite in them but not litesong. Best to Google for "litesong" ethanol. Some of the hits seem like they're from places like boardreader.

I have to go 20 miles to get pure gas unfortunately, and the price differential ($4.44 versus $3.29 as of today) is not worth that 3-7% improvement unfortunately. ;(

Which brings up the question how far should you drive, and how much should you pay?

A 10 gallon fill-up has 334 kWh of energy (pure gas) and E-10 has 323 kWh, for a difference of 11 kWh. A Prius gets about 2.3 kWh per mile. So if one has to drive 2.4 miles out of their way (4.8 miles round trip), pure gas isn't worth it from an energy standpoint. Lesser cars have an even smaller distance they should be willing to drive.

If one is paying (as I am) $3.40 per gallon for E-10, then one should only be willing to pay $3.52 for non-ethanol gas.

As an aside, no one should use PURE gasoline (if there is such a thing). The additives in gasoline are important. So, make sure you know what is being used in place of the ethanol.

Well, I *d0* know that it's ethanol-free (Sinclair-branded) unleaded gas (labeled as Premium), though I couldn't tell you what specific additives are used. I just wanted to try a tank as an experiment...the cost definitely can't be justified as you clearly demonstrated.

IIRC, lead compounds in gasoline were used for their excellent anti-knock properties. When the problem of lead in the environment became a recognized problem, MBTE was substituted. When it was discovered that MBTE did not break down and showed up in our water supplies, ethanol was substituted. So far, ethanol is the anti-knock chemical of choice because it DOESN'T POISON US. I think that people forget why ethanol was added to gasoline in the first place. If it's taken out, the anti-knock properties have to be restored using chemicals that are far more dangerous to our health. As the natural octane number for ethanol is something like 118, a more suitable substitute would be hard to find. A slight decrease in efficiency is a small price to pay to protect the health of my family.

Be that as it may, I do have one anecdotal story about ethanol-free gas. It took a trip through northern New England sometime around 2006 or so. I tanked up a few times with ethanol-free gas (that doesn't exist in MA where I live). My car, which ALWAYS achieved 33.6 MPG on trips, was returning 36 MPG with the good stuff. The new-found power was fun. I don't think ANYONE passed me on my return from southern ME to MA. Anyway, back to MA, back to 10% ethanol, back to normalcy.

If Ethanol, according to the U.S. Government, is
some type of wonder fuel, why, why, why, does
the same U.S. Goverment not use Ethanol Blend gasoline
when they conduct the Official U.S EPA Fuel Economy
Estimates????

well u probably gone by now, but i post anyway. by volume, ethanol has less power so E10 (10% ethanol which is best you can get in WA) so you will lose a few miles per gallon. the percentages vary but can go as high as E85 (not to be confused with M85 which is a methanol blend which has a HUGE drop in mileage) and you will lose about 20% of your mileage.

as far as the data you have collected. there are other variables that affect your mileage MUCH more than the type of gas you are using. you dont have enough data to make a true comparison

also, higher octane gas is a waste of money and not needed for your Prius. there are a few here that say they get better gas mileage and that is probably true, but its not the higher octane gas that is doing it

What blend would they use? E85 & E10 are already common. E15 is right around corner. E20 may emerge before the end of the decade. And how would you compare that data to older vehicles?

Remember, the estimate values are for COMPARISON. They are not intended to provide an EXPECTATION.

The Gov't could specify the rating for both Pure Gas, E-10, and E-15
if applicable. (Note: Not many cars run on E-85 ) Then, if they return honest results, we will
have an honest answer as to the discrepency of Pure
Gas vs Ethanol Blends...

This is from tests performed for the EPA by the National Renewable Energy Laboratory (whoever they are). This is a quote:
• Fuel economy decreased (7.7% on average), consistent with the energy density reduction.
This was from tests using E10 to E20.
From the horse's mouth. http://feerc.ornl.gov/pdfs/pub_int_blends_rpt1_updated.pdf
More info- click on the questions mentioning ethanol. Frequently Asked Questions

The 7.7% reduction was for E20. The 95% confidence interval was +/- 0.9% (I have rounded off to one decimal place.)

The reduction from E10 was 3.7%, +/- 0.4%.

I remember MTBE (not MBTE) and ethanol being added primarily as oxygenates:
"Oxygenates are usually employed as gasoline additives to reduce carbon monoxide that is created during the burning of the fuel."
"Oxygenates help gasoline burn more completely, reducing tailpipe emissions from pre-1984 motor vehicles"