Why does cold weather affect fuel mileage?

  1. Welcome to GM Inside News Forum – General discussion forum for GM

    Welcome to GM Inside News Forum - a website dedicated to all things GM.

    You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, Join GM Inside News Forum today!
     
+ Reply to Thread
Page 1 of 3 123 LastLast
Results 1 to 15 of 31

Thread: Why does cold weather affect fuel mileage?

  1. #1
    Banned
    Join Date
    Aug 2005
    Location
    NC
    Posts
    8,969
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Why does cold weather affect fuel mileage?

    I was reading the info on the new EPA figures for cars and trucks. They say that cold weather drops your fuel mileage. I thought cold air was actually better for an engine. They have cold air intakes on high performance cars... Someone help me out with this!

  2. Remove Advertisements
    GM Inside News
    Advertisements
     

  3. #2
    6.2 Liter LS3 V8
    Join Date
    Dec 2004
    Location
    Rockville MD/ Columbus OH
    Posts
    3,528
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    Part of it might be that engines idle faster when they are cold, using up more gas.
    Proud driver of a 1993 Jeep Grand Cherokee
    5.2 Magnum V8
    164,000 miles

  4. #3
    3.6 Liter SIDI V6
    Join Date
    Sep 2005
    Posts
    1,049
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    -Some gas condenses on the intake tract and cylinder walls when it's cold out, so in order to start the engine easily the computer needs to dump in a lot of fuel to compensate.

    -The computer makes the engine run richer to help it get warmed up more quickly.

    -Since colder air is denser, more gas is necessary in order to maintain the same air:fuel ratio. This also means the engine produces more power, BTW, which is why cold-air intakes are so popular.

  5. #4
    Banned
    Join Date
    Aug 2005
    Location
    NC
    Posts
    8,969
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    So if you garage your vehicle and keep it around 60 degrees, would it be considered cold? Also, when the vehicle warms up does it still run rich?

  6. #5
    6.2 Liter LS9 Supercharged V8 Premium Member Old Dood's Avatar
    Join Date
    May 2006
    Posts
    8,004
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    They also change the type of fuel we use...Summer Gas & Winter Gas.
    TRY to Think Outside of the Box!
    Dag-Nab-It! I missed the thread titled:"Woman Kicked Off Train After 16-hour Cell Phone Chat"

  7. #6
    7.0 Liter LS7 V8 Premium Member
    Join Date
    Sep 2004
    Location
    *
    Posts
    4,467
    Thanks
    0
    Thanked 1 Time in 1 Post

    Re: Why does cold weather affect fuel mileage?

    Quote Originally Posted by rearden82
    -Some gas condenses on the intake tract and cylinder walls when it's cold out, so in order to start the engine easily the computer needs to dump in a lot of fuel to compensate.

    -The computer makes the engine run richer to help it get warmed up more quickly.

    -Since colder air is denser, more gas is necessary in order to maintain the same air:fuel ratio. This also means the engine produces more power, BTW, which is why cold-air intakes are so popular.

    This is what I've heard too....

  8. #7
    3.6 Liter SIDI V6
    Join Date
    Sep 2005
    Posts
    1,049
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    Garaging it would help. It wouldn't need as much gas to start the engine, it won't spend as much time in "warm-up" mode since the engine is starting out at 60 degrees, and the warmer, thinner fluids would cause less parasitic loss. I forgot to mention that one in my first post, but it's a factor too.

    Most engines run rich until the coolant temperature is around 160 degrees, then it leans out the mixture somewhat. However since the engine is getting more air (because it's denser), it needs more fuel to maintain the same mixture.

  9. #8
    6.2 Liter LS3 V8
    Join Date
    Nov 2003
    Posts
    3,863
    Thanks
    1
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    Another reason is that colder temperatures make all the lubricants stiffen up on the vehicle, so there's more resistance to the moving engine, transmission, and drivetrain parts until they get thoroughly warmed.

  10. #9
    2.4 Liter SIDI ECOTEC
    Join Date
    Nov 2006
    Posts
    138
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    And, the one missed so far ... Less traction through your tires. Your tires have a MUCH larger rolling resistence when they have to roll through snow.

  11. #10
    3.0 Liter SIDI V6 smokyn454's Avatar
    Join Date
    Jul 2006
    Location
    Big Sky Country
    Posts
    528
    Thanks
    0
    Thanked 0 Times in 0 Posts
    My Ride
    2011 Dodge Charger

    Re: Why does cold weather affect fuel mileage?

    Engines do run more efficient at cooler temps, but not if the engine is cold too.

    Ideally, you want an engine at its full operating temp and to have the outside air much cooler. Say like 60 degrees or cooler. Air is much denser at cooler temps allow much more air to be inhaled by your intake. Most engines are naturally aspirated meaning they use negative atmospheric pressure to suck air into the engine. The denser the air, the more air is sucked in. Cold air intakes help get cooler air to the engine.

    This principle does not really work on supercharged or turbocharged vehicles.

  12. #11
    4.6 Liter Northstar V8 01sunfire01's Avatar
    Join Date
    Jul 2006
    Location
    CT
    Posts
    1,714
    Thanks
    0
    Thanked 2 Times in 2 Posts

    Re: Why does cold weather affect fuel mileage?

    i saw that happen in my G5 the gas miles droped the min it got cold out and i had no idea what happen. so i checked my air filter and changed my oil and still nothing. so i just put it away in my garage for the winter and brought the sunfire back out.

  13. #12
    R2-D2 Astromech Droid Smaart Aas Saabr's Avatar
    Join Date
    Oct 2003
    Location
    Montréal, Québec
    Posts
    17,638
    Thanks
    17
    Thanked 71 Times in 55 Posts

    Re: Why does cold weather affect fuel mileage?

    What doesn't cold air affect...

    Firstly, the car starts cold. So it has to run richer until warming up. The greases and oils in the engine and gearbox, and diff, and wheel bearings are cold and thick. The air is denser and the car has to work harder to push through it. The air is denser and the engine has to run with a narrower throttle opening for the same power creating more pumping losses.

    The big loss is the increased use of choke though.

  14. #13
    2.4 Liter SIDI ECOTEC pete4280's Avatar
    Join Date
    Sep 2006
    Posts
    463
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    I kind of wish i had a block heater so i could plug my car in a night. I hate how when the engine is cold the transmission doesn't want to shift up a gear. Instead it wants to keep the rpm's up i guess so that the engine warms up.

    Wouldn't mind pattle shifters

  15. #14
    R2-D2 Astromech Droid Smaart Aas Saabr's Avatar
    Join Date
    Oct 2003
    Location
    Montréal, Québec
    Posts
    17,638
    Thanks
    17
    Thanked 71 Times in 55 Posts

    Re: Why does cold weather affect fuel mileage?

    If you have a Canadian market car you should have a block heater, most Canadian models do. Open the hood and look for a covered 3 prong plug hidden somewhere. Get a timer thing, set it to turn on 15-20 mins before you leave in the morning.

  16. #15
    6.0 Liter L76 V8 MalibuMaxxSS's Avatar
    Join Date
    Oct 2006
    Location
    British Columbia
    Posts
    2,141
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Why does cold weather affect fuel mileage?

    Quote Originally Posted by Old Dood
    They also change the type of fuel we use...Summer Gas & Winter Gas.
    never heard of this b4..In Canada we use different Diesel for Winter.
    "You want free speech? Let's see you acknowledge a man whose words make your blood boil, who's standing center stage and advocating at the top of his lungs that which you would spend a lifetime opposing at the top of yours. You want to claim this land as the land of the free? Then the symbol of your country cannot just be a flag. The symbol also has to be one of its citizens exercising his right to burn that flag in protest. Now show me that, defend that, celebrate that in your classrooms."

  17. Remove Advertisements
    GM Inside News
    Advertisements
     

Quick Reply Quick Reply

Register Now

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Powered by vBadvanced CMPS v4.1.2