MPG with gas-ethanol blend vs pure gasoline

Has anyone checked gas mileage (MPG) in the identical vehicle using an
ethanol blended gasoline in one fill-up, and then pure (non-ethanol) gas
in other fill-ups? All the gas pumps in my state have an ethanol
blend, so I don't have a chance to compare with pure gasoline. I've had
people tell me that pure gas delivers measurably better MPG ... better
by 10% or more. Has anyone checked one gas against the other in the
same car? Results?
MrBear

 

In a word, no. But the debate/discussion has lots of inputs.
Simply Google: ethanol mpg

 

Ethanol has about 30% less energy in it than the same volume of
gasoline. So 10% ethanol gasoline should have about 3% less energy than
regular gasoline. And you should get about 3% less gas mileage.

Jeff

 

Esso in the province of Ontario started using ethanol last summer. Prior to
that they used MTBE, which is also an oxygenate. Before that it was MMT,
which is not an oxygenate.

With my very detailed recored keeping, I noticed a couple of percentage
point decrease in mileage when they switched from MMT to MTBE, but no
change going from MTBE to ethanol.

 

Gas has a higher btu rating than ethanol. You will get better milage out
of 100% gas.
Ive never really bothered to check the difference. When I had a 35-40mpg
vehicle driving 15-20000 mile a year gas was cheap ($.80) so didnt care.
Now I dont drive much 5000miles on a bouht new 2005Pilot. If two
stations side by side one blended, one 100% I would go with the
non-ethenol blend 100% gas.

 

(QUAKEnSHAKE) wrote in @storefull-3157.bay.webtv.net:

No fuel is "100% gas". A goodly proportion is made up of detergents and
other additives. Then you have the octane boosters.

In the old days you had tetra-ethyl lead added as an octane booster. Later
it was replaced by MMT. Neither of these had a significant impact on fuel
mileage.

What *did* finally adversely affect mileage was the addition of oxygen to
the fuel. Oxygen was added through the use of MTBE or ethanol, the
resulting fuel mix being known as "reformulated gasoline".

If you want to maximize fuel economy, you have to remove the oxygen by
going back to non oxygen-containing additives. Which ain't gonna happen.

I did, and it isn't much. Perhaps 2%. Until you do whole-year studies with
the same car, the same fuel brand and the same octane rating, it's
impossible to pick out changes that are not due to simple randomness.

You can find ethanol-free gas almost everywhere. It's usually in the form
of the the "premium" octane grades, like 91 pump octane. The lower the
octane, the higher the ethanol content. But you won't find non-oxygenated
anywhere in North America now that MMT is out of use.

 

You have that one backwards Tegger. Ethanol has a naturally high octane
variously reported at somewhere from 113 to 129 and is used in fuels
in part to increase the final octane rating.

http://www.gov.mb.ca/est/energy/ethanol/ethanolfaq.html

http://en.wikipedia.org/wiki/Octane_rating

In many cases premium fuels actually have a higher ethanol content than
their regular fuel counterparts because adding ethanol is one of the
simple ways to increase octane ratings.

John

 

I filled up today at a local Shell.

On the pump was a sticker. It said:
"87 octane: contains up to 10% ethanol
89 octane: contains up to 5% ethanol
91 octane: contains no ethanol."

Want me to take a picture and post it?

 

The difference in energy content between E10 (10% ethanol) and E0 (no
ethanol) gasoline is about 3%. At about $3.00 per gallon, that works out
to $0.09. Not enough to make using higher octane worthwhile.

Jeff

 

Post whatever you like, but the fact is that ethanol is a higher octane
fuel than standard "gasoline" and is commonly used as an octane booster.
I have no idea where you live or what the situation is with your Shell
station.

Have a look at the reference articles I posted or the dozens more which
are readily available.

 

But ethanol is not used as a fuel in road cars, only as an additive in
gasoline fuel. The Manitoba document you cite explicitly says you could
not practically use ethanol as a fuel in road-going cars.

Ethanol may be a high-octane additive, but it's a particularly poor
choice as a gasoline octane booster. Ethanol was a non-starter (ha ha)
before the government started hiding its real cost by taking money from
your left pocket so they could put it in your right, and then by
mandating the use of ethanol.

Ontario, Canada.

All the Shells in my province have that sticker, from what I've seen.

The Esso stations in my province all have stickers that say the gas "may
contain up to 10% ethanol". But then I checked the MSDS's for Esso's
unleaded gasoline. No ethanol at all, just MTBE (up to 15%).

Those pump stickers may be a legal labeling requirement rather than a
reflection of what's actually in the gas.

Shell's MSDS's do not even list the octane booster. They say only that
gasoline makes up ">90%" of the fuel mix. Shell is probably taking
advantage of the "proprietary" exemption from revealing its oxygenate in
the MSDS's.

I just did. The Manitoba government article is your typical
ethanol-loony propaganda bumpf. Manitoba farmers are reaping a
substantial financial harvest from the ethanol mandates, at the expense
of taxpayers across the country.

However, that article did contain this nugget:
"In order to produce Regular Unleaded gasoline with ethanol, a blender
must have access to an 84.5 octane (or "sub-octane") grade of petro-gas.
In some markets sub octane gasoline is not made available to blenders.
In these locations, Regular Unleaded (the lowest price grade gasoline
with the highest sales volume) does not contain ethanol. In markets
where sub octane gasoline is available, however, ethanol blended Regular
is usually less costly than petro-gas Regular."

I think the answer here may be that in my area they may be using sub-
octane to make Regular. Then they're relying on the heavy tax subsidies
that accompany ethanol to be able to offer heavily ethanolized Regular.

Grades above Regular may use better base stocks which do not require so
much ethanol to make them usable, but then the seller can't claim those
subsidies, so has to charge more.

And if our 91-octane uses MTBE instead of ethanol, there are no
subsidies at all.

 

An examble
2008 Chrysler Sebring mileage ratings
19/27 with gas
14/20 with E85 (85% ethanol)
This site shows
http://www.fueleconomy.gov/feg/noframes/24007.shtml

 

From:

Explain E85. Is using 85% Ethanol still considered an additive?

 

(QUAKEnSHAKE) wrote in @storefull-3154.bay.webtv.net:

I forgot about that. In that case the alcohol *is* being used as a fuel.

 

Check out the flex fuel vehicles:

http://www.fueleconomy.gov/feg/byfuel/FFV2008.shtml

notice how they are almost all trucks? The reason is that they get a
big credit on their CAFE when they sell a flex-fuel vehicle. So,
while you may think that your GMC Yukon only gets 15 mpg, GM gets a
credit for building a 33 mpg truck. No shit. Of course few of these
trucks will ever see E85. But the phony fuel economy rating allows GM
to sell more Suburbans, Hummers and Yukons. In this very real way,
E85 is helping to squander fuel and trash the environment.