[markus037]

I have been noticing ever since the weather has gotten colder my car is getting about 80 miles on a 1/4 tank or so. anyone esle have a similar decrease in fuel economy?

[Nonecure]

Are you using your heated seats and heated steering wheel? If so, they draw a lot of current from the alternator which means worst gas mileage.

[markus037]

i use my heated seats everyday.

[MTTH]

Originally Posted by Nonecure

Are you using your heated seats and heated steering wheel? If so, they draw a lot of current from the alternator which means worst gas mileage.

Wow I had no idea

[Nonecure]

Originally Posted by markus037

i use my heated seats everyday.

Depending on what heat setting and if both seats are on, it could add up to about 1-4 mpg difference. I typically see 2 mpg less and I use both the heated seat and steering wheel.

[peterparker]

It's winter gas. It has more oxygen molecules to help warm up your car faster!

Also the cold denser air doesn't really help gas milage either.

Snippet from: http://newsroom.aaa.com/2013/06/what...lend-gasoline/
The US Environmental Protection Agency (EPA) says conventional summer-blend gasoline contains 1.7 percent more energy than winter-blend gas, which is one reason why gas mileage is slightly better in the summer. However, the summer-blend is also more expensive to produce, and that cost is passed on to the motorist.

[Asianoak]

I seem to remember reading that here in Oregon there is typically a higher percentage of ethanol added in the winter for emissions reasons. Since ethanol has a lower overall energy potential than standard gasoline (I'm sure my terminology is incorrect but the idea is the same so no need to jump all over me if you're a pro ethanol guy) it does effect mpgs. I've been able to find a few stations in town that sell ethanol free gasoline and it makes a big difference in both of my bimmers. So combine this with increased electronics usage as mentioned above as well as possibly lower tire pressure due to colder denser air and you could be losing quite a bit of the course of one tank. Not sure if the ethanol issue is true in all states so you may want to check your with your local stations.

Btw, ethanol free gasoline is typically more expensive so I did a quick comparison based on fuel mileage and actually found that paying extra for the ethanol free pays for itself in increased fuel mileage. I run it year round now. The station attendants all know me and my cars and have mentioned that they do have a dedicated group of customers who will put nothing else into their cars.

[Asianoak]

Oh and not to state the obvious but hopefully you're not letting your car warm up for 15 minutes every morning before driving... Biggest waste of gas there is.

Ever notice that the people who complain about gas prices being too high or food prices being too high, etc etc are the people who are the most wasteful? I went grocery shopping the other day and this fat dirty couple were sitting in their car with the windows down complaining about some financial thing... The cost of groceries or something. Naturally, the car is running with the windows down and heater on. When I come out 15 minutes later they are still there, still arguing, car still running, windows still rolled down. The money they wasted on gas probably would have paid for the ho hos he wanted and of course if they'd stood up and walked around to actually pump some blood and burn some calories they wouldn't have needed to have the car running and might have discovered how good exercise felt. Sorry for the rant, here in Central Oregon it gets frustrating being surrounded by so many people with absolutely no aspirations in life or sense of responsibility... Gimme gimme gimme. Ugh. Okay, end of rant.

[markus037]

i never let my car idle, maybe 30 seconds til the idle drops below 1,000 rpms. i usually just hop in and go. i know this warms the car up faster and uses less gas.

[iDriveanXi]

Yup hop in and go. I keep it 3k or under until the oil temp needle moves to about 180 then I Rev it more.

[critical05]

Originally Posted by Asianoak

I seem to remember reading that here in Oregon there is typically a higher percentage of ethanol added in the winter for emissions reasons. Since ethanol has a lower overall energy potential than standard gasoline (I'm sure my terminology is incorrect but the idea is the same so no need to jump all over me if you're a pro ethanol guy) it does effect mpgs. I've been able to find a few stations in town that sell ethanol free gasoline and it makes a big difference in both of my bimmers. So combine this with increased electronics usage as mentioned above as well as possibly lower tire pressure due to colder denser air and you could be losing quite a bit of the course of one tank. Not sure if the ethanol issue is true in all states so you may want to check your with your local stations.

Btw, ethanol free gasoline is typically more expensive so I did a quick comparison based on fuel mileage and actually found that paying extra for the ethanol free pays for itself in increased fuel mileage. I run it year round now. The station attendants all know me and my cars and have mentioned that they do have a dedicated group of customers who will put nothing else into their cars.

It's not ethanol, it's butane that used in winter gas. It also makes winter gas slightly cheaper than summer gas since butane is inexpensive.

[Asianoak]

Originally Posted by critical05

It's not ethanol, it's butane that used in winter gas. It also makes winter gas slightly cheaper than summer gas since butane is inexpensive.

Oh... You're right. My bad.

I still like to stick with the ethanol free whenever possible due to it's higher energy and lower corrosive effects on the fuel system. I'd encourage anyone who hasn't already to read about gasoline additives, summer and winter blends and the effects of ethanol. Really interesting stuff.

[blown07]

Originally Posted by Nonecure

Depending on what heat setting and if both seats are on, it could add up to about 1-4 mpg difference. I typically see 2 mpg less and I use both the heated seat and steering wheel.

heated seats are about 50 watts each or less than 1/10 of a hp each so I doubt your're gonna see any diff in mpg

[E94]

Yep, I have also noticed a decreased mpg in the winter.

I am getting around 18-19 in the winter and around 20-22 in the summer.

Mainly city driving.

I have noticed in the winter you are also braking a lot more and not driving as steadily as you would in more clear weather.

[Nismo G]

I have noticed a decrease in mileage as well. I always thought it was just due to the cold air...im prolly getting about 17-19mpg on average right now

['02onthebrain]

I am getting less mpg as well. I suspect winter gas and I can feel my car in AWD more often with the bad weather.

[anthony.]

i see you are ASE certified. i myself am a master tech, and am surprised you have came here with question which you should already know the answer too.. (not trying to be rude)

winter blend gas, colder air.. more fuel...

colder air =lower tire PSI,
denser air= more aero drag..
etc..

as far as heated seat/steering. that barely affects gas mileage. does put more on the alternator but nothing where even you should notice a .1-2 mpg difference.

and no, using the heater does not affect gas mileage. A/C is a different story.

[Nonecure]

Originally Posted by anthony.

as far as heated seat/steering. that barely affects gas mileage. does put more on the alternator but nothing where even you should notice a .1-2 mpg difference.

I really thought the heated seats used much more than 45 watts, so my estimation on gas mileage was way off. So yes you are correct that you might not really see much of a hit on your gas mileage from using them. But I wanted to make sure everyone knows that the more current you pull, the more gas you will burn. This is why the new BMW's now charges the batteries when you are braking.