Is your gas mileage decreasing

[Dick Adair]

For the last 2 weeks I have noticed small signs on the gas pumps in our area. (South central PA, Lancaster County). "This fuel contains less than 10% ethanol." It is all the pumps and you have no other choice. I don't think it is my imagination, but my fuel economy seems to be a lot less. 230-240 miles compared to 280-300 miles per fill up, which is about 15-16 gallons per fill. Most of my driving is local. I'm curious if other areas of the country have this? I have not heard anyone else complain about it, but it actually increases your cost of driving another 10-15%. What a deal, they use corn to make ethanol, which increases the cost of food, then put the ethanol into the tank which decreases the fuel octane and your mpg. Am I missing something here?

[Jim Becker]

Many vehicles get less mileage the colder it is and we've finally had a bit of colder temps here in PA. But I, too, am not largely in favor of increasing use of Ethanol for fuels, both due to the high energy cost to produce it and the way that food prices are being skewed upward further as farmers switch to producing more corn, rather than other food crops. This is a tough situation, however, as there truly is a need to be less dependent on fossil fuels over time, and Ethanol also "can" burn cleaner with an engine properly tuned for it.

BTW, those of us who drive hybrids also have our worst mileage during the coldest weather as battery technologies available today are much less efficient when they are cold. I take about a 3 MPG hit on my Highlander at this time of year, although I can't complain too much about just under 25 mpg in a mid-sized SUV.

[Tim Malyszko]

I too have seen a drop in gas mileage this winter and attribute it both to the cold and to the 10% ethanol blend. Ethanol actually has almost 50% less potential energy than gasoline. So, if your car/truck normally gets 20 mpg on 100% gasoline, a 10% blend of ethanol will reduce your mileage by about 1 mpg. Then, throw in the cold factor, you will see another mile or two reduction. Remember that most people "warm" their car in the morning and keep it idling more often when its cold out, so that too plays into the reduced gas mileage.

This winter, I've experienced almost a 3 mpg drop in fuel efficiency. I use to fill up around 250-250 miles, but I'm now filling up around 210-220 miles and putting more fuel in than before.

Also, all the funky "state specific" blends of gasoline required to meet State EPA regulations are affecting it. I'm not sure how, but ever since this became a big deal, my MPG went down.

[Jim O'Dell]

It's been reported here, IIRC, about the amount of energy in gas vs ethanol. There is a big difference. I work for a car dealership service department and I hear it almost every day. Personally, I haven't noticed a hit in mileage on my 2002 E250 ext van. It's not a flex fuel design either. But then, I don't drive over 62 mph, and I do very easy accelerations and decelerations. My wife's 1999 Gr. Caravan is a flex fuel design, and I think it takes about a 1 to 1.2 mpg hit on the ethanol fuel. But then, she drives a lot more than I do, and probably a little faster. Jim.

[Joe Pelonio]

I have always found a 2-3 MPG decrease in winter, and blames it on the E10 but then it could be the weather too I suppose. On the other hand, I made a recent trip to my Mom's driving 3 hours and part way back before filling up it calculated out at 25MPG, the best I'd ever gotten, and amazing for a 4.0 V6 4x4 Ranger. I attribute that to the fact that I had no traffic all the way and was able to use cruise control all but a few miles of the trip.

[Ken Werner]

Ethanol carries less energy per gallon tha gasoline. I have found that I get significantly worse mpg using 10% ethanol fuel. And it is not compensated for by the slightly lower price of the mix.

Cold temps also reduce mpg.

Ken

[Mike Henderson]

Ethanol is added to gasoline to raise the octane rating, but it contains less energy than gasoline so your gas mileage suffers. Even at 10% ethanol you'll see a significant (at least I consider it significant) decrease in miles/gallon compared to gasoline with no ethanol.

I was driving cross country and drove through the corn belt. I have a trip computer on the car that measures miles/gallon. I thought something was wrong with the car because the miles/gallon decreased from about 25 MPG to about 21MPG. But when I left the corn belt, my gas mileage went back to what it had been before. The corn belt states mandated use of ethanol to create a market for their farmers' corn. Now, most of the country gets to enjoy ethanol in their gasoline.

Mike

[Greg Peterson]

We've been getting the 'winter blend' gasoline for years now. Long before any considerations were given to bio-fuels. Heck, the word wasn't even in the vernacular.

The state department of environmental quality mandated the winter blend (ethanol) to reduce emissions in the winter months. Being our metro area is in a valley, certain gas emissions can accumulate during winter months. The ethanol additive is suppose to reduce these gases.

That's the story they tell us anyway. Been that way for 15 years or so.

[Roy Hatch]

Rolling resistance is increased by underinflated tires, thus more gas is used. Tire pressure may drop approx 1 psi for each 10 degree drop in temperature. This can be significant for those who don't check tire pressure as temperatures drop in the winter. Of course we all have compressors, so that shouldn't be a problem.

[Jason Roehl]

http://www.epa.gov/otaq/rfgecon.htm

Ethanol does not have 50% the energy gasoline does, it's closer to 70%, so assuming your car is running and tuned properly, switching to E10 (10% ethanol, 90% gasoline), should only hurt your mileage by about 3%. If your mileage was 20.0 MPG, then it might drop to 19.4 MPG or so because of the switch. Cold air has a far greater (negative) effect, and the comment about the impact of low tire pressures is spot-on. I always run close to the max listed on the sidewall of my tires and have never had the tires wear in the center like that is supposed to cause.

[Ron Dunn]

Jim O'Dell, are you seeing any damage to vehicles from ethanol blended fuel?

When it was first trialled in Australia, many older cars experienced fuel system problems, eventually leading to engine damage. It is not recommended here for any car older than (I think) 10 years.

What is the US experience?

[Curt Harms]

I seem to recall that engines running on mostly or all ethanol can run higher compressions due to higher octane (knock resistance) which can recover some of the mpg hit. Anybody know about that?

Curt

[Kyle Kraft]

Around here there are a few stations that have an E85 pump (85% ethanol 15% gasoline). According to the motorheads that I work with, the fuel efficiency of an E85 burning vehicle is lower when compared to the equivalent gasoline burner. The E85 fuel costs maybe $0.20 less than the current gasoline price, but you burn more of it. So to me the only reason to use it is the alleged environmental benefits, whatever you believe them to be.

[Jason Roehl]

Jim O'Dell, are you seeing any damage to vehicles from ethanol blended fuel?

When it was first trialled in Australia, many older cars experienced fuel system problems, eventually leading to engine damage. It is not recommended here for any car older than (I think) 10 years.

What is the US experience?

E10 first came around in about the mid-80's and caused some problems during the summertime with "vapor-lock." I think this was mainly older carbureted vehicles, and there may have been some problems with fuel lines also. Virtually everything on the road now can handle the E10, even vehicles that are up to 20 years old (my vehicles are a '93 and '96, no fuel system problems). E85 is another ballgame altogether. Vehicles MUST be flex-fuel equipped to run that stuff, or fuel lines and seals can fall apart, and they probably can't produce the proper fuel-air ratios, either.

[Ken Garlock]

Energy content that is.

Ethanol contains only 66% of the energy that the same measure of gasoline contains. Ethanol contains around 76,000 BTU/gal. while gasoline contains about 114,000 BTU/gal. Simple arithmetic shows that it takes 1 1/2 gal of ethanol to produce the same BTU content as in 1 gal of gasoline. Or, 3 gal of ethanol to match 2 gal of gasoline. Hence, ethanol should cost 66% as much as gasoline in order to maintain the same price per BTU. Never happen!

You green gents might want to notice that the price of wheat has reached $10/bushel for the very first time because the farmers are all rushing to make money on corn for ethanol. Can you say $1.50 doughnut, and $8 loaf of bread. I would rather buy groceries than wring my hands over how to fuel a car.