Summer vs Winter Gas

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...

Reply to
Larry Davis
Loading thread data ...

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:

Reply to
Bonehenge

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

Reply to
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

Reply to
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

Reply to
Carl 1 Lucky Texan

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?

Reply to
BobN

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.

Reply to
Frank

Carl 1 Lucky Texan wrote: ....

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

Reply to
Mickey

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.

Reply to
Some O

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......

Reply to
cupidstoy

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.