Outside temperature and MPG

[daveyrach]

Morning All

Was just sat at work wondering after filling in my Fuelly.com entry, is MPG connected outside temperature?

As the summer has drawn to a close my MPG has slowly reduced.

[MJC-DEV]

Yes, more choke is required to start a colder engine. Not sure about when warm and running though.

[wideguy]

Yes, MPG will be higher in warmer weather. Factors include air density, warm up time, air resistance, rolling resistance and gasoline formulation.

[Paul the 6th]

I'm no expert but the basics of it are, the more air you can get into the engine, the more fuel goes in, the more power you get out. Colder air is denser than warm air, so a dry road on a frosty day, the engine may potentially feel slightly more perky.

[yorkie_chris]

More time spent on choke before it's warm.

I think rest of factors are minimal and probably cancel out to some degree or are lost in the rest of the "noise" that comes with measuring economy.

[daveyrach]

Cheers guys, odd thing is I rarely use the choke, only when it gets really really cold which it isn't yet.

[Bibio]

as it gets colder/wetter your speeds reduce so it makes sense then your MPG will be better. yes cold air is better than hot air but in reality it makes no fekin difference unless you have carbs that like to ice up.

[jambo]

Are you using the air conditioning more in the colder weather? That can make a difference...

Jambo

[wideguy]

http://www.scientificamerican.com/article.cfm?id=why-is-the-fuel-economy-o
Lots of information like this is available just by using Google.

[Paul the 6th]

Are you using the air conditioning more in the colder weather? That can make a difference...

Jambo

:winner: LAD