How does the weather affect gas mileage, you ask?

[Jeff7181]

I have this app on my iPhone that I use to track my mileage. The graph is a bit deceiving because it's such a narrow view of the graph, but you get the idea. My mileage was about 26 mpg in the winter and is about 28-29 now in the summer.

 

[jlee]

Winter fuel blends FTL

 

[Jeff7181]

Winter fuel blends FTL

If it was fuel and not weather, wouldn't it be a more severe step up in mileage when the station cuts over to the summer blend? I fill up at the same pump at the same station every time unless I'm out of town.

 

[herm0016]

pushing snow around and letting the car warm up effect the milage a lot more than the fuel blend.

 

[PingSpike]

I know my studded tires can't be helping my winter fuel economy either.

 

[RedRooster]

I'd imagine you let you car idle a lot more to warm up in the winter. No one wants to get in a cold car.

 

[TakeNoPrisoners]

pushing snow around and letting the car warm up effect the milage a lot more than the fuel blend.

Must be this. I've never seen such a big change from winter to summer in california.

 

[Bartman39]

Taken from here...
http://ask.cars.com/2009/02/whats-t...blend-gasoline-does-it-affect-my-cars-pe.html

Cars using summer-blend gasoline spew fewer harmful emissions and get slightly better fuel economy than those using winter-blend gas during the summer months.
The difference between conventional summer- and winter-blend gasoline has to do with the Reid Vapor Pressure of the fuel. RVP relates to the volatility of a gasoline. The more volatile a gasoline, the more likely it will evaporate as the temperatures rises; evaporated gasoline contributes to unhealthy ozone and smog levels. Summer gasoline has a low RVP and is less likely to evaporate when compared to the high RVP winter grade. The Environmental Protection Agency says conventional summer-blend gasoline contains 1.7 percent more energy than winter-blend gas, which contributes to the summer blend’s slightly better gas mileage.
The Energy Information Administration says the switch between the two fuels happens twice a year, once in the fall (winter blend) and again in the spring (summer blend). Summer-blend gasoline is typically more expensive to produce than the winter blend, and it won’t affect vehicle performance or the durability of the engine and fuel system, according to the EPA.
In many large cities as well as California and New England, the EPA requires the use of reformulated summer- and winter-blend gasolines. These RFGs contain oxygenates that lower RVP and other toxic chemicals even further than conventional gasoline.

There is also a good article about Why are diesel engines more efficient?:thumbsup:

 

[Jeff7181]

I'd imagine you let you car idle a lot more to warm up in the winter. No one wants to get in a cold car.

Honestly, I don't for a couple reasons. First, the cold doesn't bother me THAT much. Second, idling doesn't warm up the engine efficiently... yeah, you get warm air out of the vents within about 5 minutes, but the oil temp isn't where it should be to be considered warmed up and these engines have some scary piston slap when cold, so I like to warm it up as quickly as possible, which is best done by driving.

I don't end up pushing much snow. They have my parking lot plowed before I leave in the morning and all the roads I take to work are plowed by the city or county.

 

[Jeff7181]

Must be this. I've never seen such a big change from winter to summer in california.

Does the temperature differ by 90 degrees, though? I live in Michigan. It gets into single digits in the winter and approaches 100 in the summer.

 

[jlee]

Must be this. I've never seen such a big change from winter to summer in california.

Are you talking about weather or gasoline? :awe:



There are a lot of factors involved - warmup/idling can be huge, and winter tires will drop fuel mileage as well. Unless I'm mistaken, winter fuel has less energy per gallon, which also doesn't help matters.

http://ecomodder.com/forum/showthread.php/mpg-decline-colder-weather-winter-blend-gas-11090.html

Does the temperature differ by 90 degrees, though? I live in Michigan. It gets into single digits in the winter and approaches 100 in the summer.

Same here, except double digits below zero on the low end.

 

[Jeff7181]

This coming winter will be interesting. I wonder if I'll see any difference now that the car is fully broken in.

 

[Demo24]

I actually find the opposite in my car. I tend to get a bit better in the winter compared to summer. Perhaps aircon usage in summer, or maybe the denser air helps it run a bit leaner in winter I don't know.

 

[Jeff7181]

I actually find the opposite in my car. I tend to get a bit better in the winter compared to summer. Perhaps aircon usage in summer, or maybe the denser air helps it run a bit leaner in winter I don't know.

What kind of car do you have?

 

[Demo24]

What kind of car do you have?

Subarau WRX, it's much happier in the cooler temps. Might be getting a bit of heatsoak on the intercooler in these hot conditions.

 

[Doppel]

I've seen arguments about how severe the impact of driving in the rain is, too. The tires throw a lot of water up and by calculating how much water they throw up the energy required to do it is surprisingly substantial.

 

[Bartman39]

Subarau WRX, it's much happier in the cooler temps. Might be getting a bit of heatsoak on the intercooler in these hot conditions.

Whole reason for the intercooler is cool down the intake charge which makes it denser so more power which means more a efficient burn which the end result is more MPG if you keep your foot out of it... Cooler weather will most always make a turbo car/truck run better and stronger...

 

[Jumpem]

My Outback does 30mpg in the summer and 25-26mpg in the winter.

 

[TakeNoPrisoners]

Does the temperature differ by 90 degrees, though? I live in Michigan. It gets into single digits in the winter and approaches 100 in the summer.

It gets to the mid twenties at the coldest, and only for a day or two and only at night, 110 easy in the summer. The last snow was at least 12 years ago.

Are you talking about weather or gasoline? :awe:



There are a lot of factors involved - warmup/idling can be huge, and winter tires will drop fuel mileage as well. Unless I'm mistaken, winter fuel has less energy per gallon, which also doesn't help matters.

http://ecomodder.com/forum/showthread.php/mpg-decline-colder-weather-winter-blend-gas-11090.html



Same here, except double digits below zero on the low end.

Im talking about MPG. The MPG here stays the same pretty much no matter the season. I usually get like 13-15 MPG all the time.

If I had a car that got better MPG I'm sure I would see a difference, with these low numbers the changes could be margin of error.

 

[Demo24]

Whole reason for the intercooler is cool down the intake charge which makes it denser so more power which means more a efficient burn which the end result is more MPG if you keep your foot out of it... Cooler weather will most always make a turbo car/truck run better and stronger...

I understand the function of an intercooler and how it works, just suggesting this might be a reason why my mpg's increase in the cooler perods whereas many vehicles demonstrate a decrease.

 

[Bartman39]

I understand the function of an intercooler and how it works, just suggesting this might be a reason why my mpg's increase in the cooler perods whereas many vehicles demonstrate a decrease.

No problem just agree with with you that turbo charging and cooler weather and no matter the fuel (winter or summer) will increase MPG and your WRX is proof for the winter mix...:thumbsup:

BTW they do also change the winter/summer blend with diesel as well but mainly for the gel point...

 

[Jeff7181]

No problem just agree with with you that turbo charging and cooler weather and no matter the fuel (winter or summer) will increase MPG and your WRX is proof for the winter mix...:thumbsup:

BTW they do also change the winter/summer blend with diesel as well but mainly for the gel point...

I don't know about that... turbo charging and cooler weather will increase power, I agree. An increase in power doesn't exactly translate to increased MPG.

One could say that if your engine makes more power at a specific RPM due to turbocharging or a cooler, denser air/fuel charge you won't need to open the throttle as much or for as long to accelerate at your desired rate/to your desired speed. You may save fuel because of this.

However, at cruising speed where you're just maintaining a constant speed a turbo charger isn't going to increase your mileage, nor will cooler air. Due to gearing, if your engine must be running at 2000 RPM to maintain speed and the engine is perfectly capable of making the power required to maintain the speed with a hot air charge then having a cold, dense air charge just means the computer will have to add more fuel to keep a reasonable air/fuel ratio.

 

[T2urtle]

i get better MPG in the rain, mainly because i tend to drive at speed limits then.. =P

 

[MovingTarget]

pushing snow around and letting the car warm up effect the milage a lot more than the fuel blend.

Wait, what is this snow you have to push around?

<--Southerner

For us, we see higher mileage in winter. This is usually attributed to the fact that air conditioning is almost a requirement for not arriving at your destination completely soaked in sweat during the summer months.

 

[Zenmervolt]

I actually find the opposite in my car. I tend to get a bit better in the winter compared to summer. Perhaps aircon usage in summer, or maybe the denser air helps it run a bit leaner in winter I don't know.

Has to be aircon or more traffic in the summer or something of that sort. EFI systems don't change the mixture, so the colder, slightly denser air in winter would simply cause the ECU to inject more fuel to keep the mixture ratio the same. The car doesn't "run leaner" in the winter.

ZV