Summer vs Winter Gas

[Larry Davis]

Hi,
Can anyone explain what the difference is between summer and
winter gas - and why my mileage drops in winter? I've heard the
winter blend is "oxygenated" - why the change and what exactly are
they doing to the gas?

Here in Illinois, my 2003 Forester XS gets 27-28 mpg in mostly
highway driving - in summer. As soon as it gets cold, that will
drop to 23-24 mpg, same driving situation. This is using same gas
brands - all with ethanol.

What makes me crazy, a friend who drives Hondas says his mileage
is same , year round. My wife's Chevy Cavalier (!), gets 29 -30 mpg
year round. Why is Subaru not able to compensate for the gas
difference?

I've tried the pull the battery cpu reset - the car just drives
poorly for awhile, then back to same situation after 2 or 3 tankfuls.
Thanks, in advance, for any info...

 

[Bonehenge]

Hi,
Can anyone explain what the difference is between summer and
winter gas - and why my mileage drops in winter? I've heard the
winter blend is "oxygenated" - why the change and what exactly are
they doing to the gas?

In my area, MTBE used to be added in the winter, which was replaced
with 10% ethanol for environmental reasons.

Now that we have 10% ethanol all the time, I don't think we'll have
"winter" gas anymore.

Required fuel blending details are often explained on state motor
vehicle or consumer protection dept. websites. You may find more
specific details there, along with here:

<http://www.epa.gov/otaq/rfg/faq.htm>

 

[Frank]

Hi,
Can anyone explain what the difference is between summer and
winter gas - and why my mileage drops in winter? I've heard the
winter blend is "oxygenated" - why the change and what exactly are
they doing to the gas?

Here in Illinois, my 2003 Forester XS gets 27-28 mpg in mostly
highway driving - in summer. As soon as it gets cold, that will
drop to 23-24 mpg, same driving situation. This is using same gas
brands - all with ethanol.

What makes me crazy, a friend who drives Hondas says his mileage
is same , year round. My wife's Chevy Cavalier (!), gets 29 -30 mpg
year round. Why is Subaru not able to compensate for the gas
difference?

I've tried the pull the battery cpu reset - the car just drives
poorly for awhile, then back to same situation after 2 or 3 tankfuls.
Thanks, in advance, for any info...

I believe winter gas has a lot more butane in it. I have a
polyethylene can of each in garage for my generator and the winter gas
can, with higher vapor pressure, is bulged slightly more. The whole
oxygenate thing is a scam foisted on us by agricultural interests led
by Archer Daniel Midlands. Alcohol was touted for pollution control but
gas companies said they could get same result without it. Data I've
seen is tenuous. Alcohol has about 40% less energy than gasoline and
the 10% blend may lead to a mile or two less per gallon. In addition
it cannot be pipelined - must be blended and shipped in trucks which
adds extra cost passed on to us. Not to mention tax subsidies - guess
who pays them. Read recent consumer report article.
Frank

 

[DK]

The whole
oxygenate thing is a scam foisted on us by agricultural interests led
by Archer Daniel Midlands. Alcohol was touted for pollution control but
gas companies said they could get same result without it. Data I've
seen is tenuous. Alcohol has about 40% less energy than gasoline and
the 10% blend may lead to a mile or two less per gallon. In addition
it cannot be pipelined - must be blended and shipped in trucks which
adds extra cost passed on to us. Not to mention tax subsidies - guess
who pays them. Read recent consumer report article.
Frank

To put it plainly, ethanol in gasoline is a hidden taxation aimed to
subsidize corn farmers (who then vote for crooked politicians
that put those taxes in place).

I once calulated - using currently avalable fairly optimistic numbers
given by ethanol fuel proponents - how much corn we'd have to
grow in order to substitute gasoline in cars completely. The short
of it is even if corn grows on every square inch of the USA land,
there is not enough land available.

DK

 

[Carl 1 Lucky Texan]

To put it plainly, ethanol in gasoline is a hidden taxation aimed to
subsidize corn farmers (who then vote for crooked politicians
that put those taxes in place).

I once calulated - using currently avalable fairly optimistic numbers
given by ethanol fuel proponents - how much corn we'd have to
grow in order to substitute gasoline in cars completely. The short
of it is even if corn grows on every square inch of the USA land,
there is not enough land available.

DK

I can believe it.
the number I saw said if every square inch of California were growing
corn, it might meet one tenth the US gasoline demand. The cost of animal
feed is already going up, which will translate into higher meat prices.
Growing food for cars seems immoral.

Carl

 

[BobN]

Growing food for cars seems immoral.

Certainly true in the case of alcohol, but not necessarily for vegetable
oil. Using veggie oil in diesel motors is a much more direct way to
transfer solar energy into motive power and the oil has a much higher energy
density than ethanol. it also doesn't suffer from the soot/sulfur problems
that are delaying expansion of petro-diesel in the US. You're right that
ethanol is a corrupt politically-driven perversion of natural market forces.
Where is the brave presidential candidate who will go to Iowa in primary
season and try to persuade the farmers to grow something else?

 

[Frank]

Certainly true in the case of alcohol, but not necessarily for vegetable
oil. Using veggie oil in diesel motors is a much more direct way to
transfer solar energy into motive power and the oil has a much higher energy
density than ethanol. it also doesn't suffer from the soot/sulfur problems
that are delaying expansion of petro-diesel in the US. You're right that
ethanol is a corrupt politically-driven perversion of natural market forces.
Where is the brave presidential candidate who will go to Iowa in primary
season and try to persuade the farmers to grow something else?

Bio-diesel is more efficient to produce than ethanol. You still only
get out 40-60% more energy than you put in vs maybe 20-40% more for
ethanol. (It is probably more efficient to produce ethanol from
petroleum - at least it used to be.) For biodiesel in warm climates,
you don't have to convert the natural glycerol esters to methyl esters
so they don't solidify in the cold. They say Willie Nelson's bus
smells like a burger joint from burning used cooking oil. Diesels also
get better mileage. I understand 30% of the small cars in Europe are
diesel so we'll get our Subie one eventually.

 

[Mickey]

Carl 1 Lucky Texan wrote:
.....

I can believe it.
the number I saw said if every square inch of California were growing
corn, it might meet one tenth the US gasoline demand. The cost of animal
feed is already going up, which will translate into higher meat prices.
Growing food for cars seems immoral.

Carl

You are still left with a mash that is good qlty animal
feed. Don't know if you ever raised cattle but mine rarely
eat corn. Most cattle eat hay as their prime food source.
Only when they end up in a feed lot do grains become a large
portion of their diet.

A major problem with alcohol for a good portion of the US is
the weather is too cold during the winter months for 100%
alcohol to vaporise.

Mickey

 

[Some O]

Here in Illinois, my 2003 Forester XS gets 27-28 mpg in mostly
highway driving - in summer. As soon as it gets cold, that will
drop to 23-24 mpg, same driving situation. This is using same gas
brands - all with ethanol.

On long drives my Chryslers get the same, summer or winter.
Shorter trips result in higher consumption due to the warm up.
Older cars I've had, particularly the VW bug, got lower winter mileage.
My conclusion is it's mainly due to fuel control. Also with the Subaru
flat engine design it probably takes longer for warm up, because more
engine area is exposed to the cold air.
The VW bugs used to carburetor ice so badly they wouldn't idle for
several miles on cold days.

Interesting read on E85 methanol fuel in the recent Consumer Reports.
About 27% higher fuel consumption.
Plus their interesting conclusion that USA Gov. support, giving
artifically higher EPA ratings for E85 capable vehicles, is resulting in
more gas hog vehicles being built.

 

[cupidstoy]

i think you may be missing out on two important points that can affect
mileage. tire pressure drops 1 psi per every 10 degrees and unless you
check them and keep them topped off, that could be costing you several
mpgs on very cold days.

also, all lubricants in engine, transfer cases, differentials,
bearings, etc thicken in the cold weather. good for another mpg or so.

the MAF sensor is designed to accomodate for changes in air temp and
humidity and along with the o2 sensor to adjust a/f ratios and keep the
engine running at peak efficiciency. unfortunately, that is an
imperfect system and doesn't always work as designed. a lot of people
see an increase in power and less fuel economy in cold weather. cold
air is denser and thus more oxygen enters the cylinders for combustion.
this is the principle behind a cold air or ram style intake.

there is also some argument that the density of gasoline changes with
the temperature and some volume based pumping systems do not account
for this well. gas should actually be sold by the energy value which
is constant rather then by volume which varies with temp and
atmospheric pressure, but alas, i digress......