"Winter Blend" Fuel is 2 - 8% Less Efficient? What?

[Nick]

I have never heard of this before.

http://jalopnik.com/what-you-should-know-about-the-fuel-youll-be-putting-i-1450089585/@whitsongordon

Basically fuel is cheaper in the winter but less efficient because it uses more butane so net cost is the same.

I haven't noticed my mileage dropping noticeably in the winter but maybe I'm not paying enough attention.

There's a number of differences in winter blend gasoline, but there's really two major results of these changes that you're likely to note, and they're both caused by the same thing. The first thing most folks realize is that gasoline tends to be cheaper in the fall and winter months. Some of this is due to a drop in demand, but the truth is that the gasoline blend used in those months is actually cheaper to produce.

 

[St. Bear]

2-8% would not be noticed when driving around, and would be masked by driving habits and traffic.

 

[Cornhead]

Ethanol has less energy than gasoline too, the percentage in our gas will be rising, expect your mileage to decrease.

 

[wa-loaf]

Not new info. Same with Diesel as they add anti freeze agents.

 

[Nick]

Funny, I didn't know. I'm surprised the variance is that significant, up to 8%. That sounds very significant to me.

 

[St. Bear]

Funny, I didn't know. I'm surprised the variance is that significant, up to 8%. That sounds very significant to me.

8% of 30mpg is 2.4mpg. I guarantee you can get that improvement in driving habits alone.

 

[Nick]

I guess. Still though you'd think over time... I am pretty consistent on my car to getting 315 miles out of 11.5 gallons

 

[Geoff]

The drop in fuel economy is mostly due to the increased density of colder, dryer winter air. The engine will also be much less efficient until the oil warms up so a car that only goes a couple of miles in the winter and rarely warms up completely will get lousy fuel economy.

Butane contains less energy per cubic foot than gasoline; the additional butane found in winter-blended gasoline results in a net energy loss of about 1.7 percent (114,500 BTUs per gallon for a summer blend, 112,500 BTU for winter blends). As such, using winter-blend gas will result in a maximum 1.7 percent reduction in fuel efficiency. However, bear in mind that the butane's additional volatility can hypothetically offset its energy deficit, allowing a cold engine to more efficiently combust its fuel. But since this additional volatility may or may not help a particular engine, it's better just to assume a maximum 1.7 percent loss.

Read more: http://www.ehow.com/info_12071245_low-gas-mileage-winter-due-blending.html#ixzz2iZfaacma
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[Edd]

The drop in fuel economy is mostly due to the increased density of colder, dryer winter air. The engine will also be much less efficient until the oil warms up so a car that only goes a couple of miles in the winter and rarely warms up completely will get lousy fuel economy.

This has always been my impression. I've never heard that there's an actual change in the fuel formula in the winter. Of course, my driving during the winter quadruples due to skiing.