Cold/denser air & fuel economy?

[Spiderman]

We all know that colder/denser air results in increased power, but does anybody know if the colder denser air also results in increased fuel economy too? (even in theory) I haven't noticed anything different at the pumps lately, but my driving habits and traffic aren't consistent, so it's difficult to gauge.

Just curious.

TIA 8)

[Pharmgirl]

Colder, denser air makes fuel economy worse, since it is harder to combust the gasoline at colder temps and takes longer to get your engine warm, and the density of the air changes your flow through it, making it more difficult. It also changes your tires and tire pressure which which doesn't help either.

I notice a significant decrease in fuel economy in my car as soon as it turns cooler. Usually 40-50 less miles per full tank.

[rybo]

A couple of things,

There are a lot of factors that play into this equation:

1) Air density - offers the opportunity to burn MORE fuel, (ie make more power), but that doesn't mean that it's burning the same amount of fuel more efficiently.

2) The engine doesn't achieve peak efficiency because it takes longer to reach operating temperature (requiring a richer fuel mixture)

3) Gas is reformulated in the winter to provide easier starting in cold conditions. This may or may not decrease it's energy value, but it's not an apples to apples comparison.

In the end I would guess that if you saw an increase in economy on the bike in colder weather it's because your riding habits have changed a bit and you've slowed down rate of acceleration, rate of travel or something of that nature. In cars I would guess the average commuter will see a decrease in economy during the winter months.

Scott

[King Nothing]

Just don't vote for Obama

[dapper]

EPA (http://www.epa.gov/otaq/oxygenate.htm)

Increased density of the air will create more drag and require more fuel to be burnt to maintain a consistent speed. This is one reason why planes fly high.

Oxygenated fuel (http://www.epa.gov/otaq/regs/fuels/ostp-3.pdf)

If you're looking to reduce fuel consumption on your bike. Change your sprockets to make the gears taller. This will lower your rpm's and reduce fuel usage.


It is difficult to get a man to understand something when his salary depends on his not understanding it.

Upton Sinclair (1878–1968 ), American writer

[Joe]

According to ecomodders.com, HOTTER air results in increased fuel mileage for FUEL INJECTED vehicles, since the Mass Air Flow Sensor detects less oxygen and therefore gives less fuel. Their theory is less power=less fuel. Many people on that site have created WARM air intakes to trick the MAFS into giving less gas to the engine.

Now, back to reality...
Even on my worst day EVER, at the Pueblo racetrack, I STILL got 45mpg. Yes, I'm a nerd for recording my mpg even at a racetrack. So, with gas prices falling, and the gas mileage of even a "high performance" motorcycle averaging around 50, I don't think we should worry.

[Spiderman]

:lol: I wasn't worried, nor had I noticed any change, I was just curious. I've noticed the colder temperatures, and remembered Dana's thread about increased performance, so I was just wondering if any of the smart people out there could edumacate me. :D

Thanks y'all. 8)

[Devaclis]

I noticed on the Hawk, which I rode in the winter for 2 years, that I dropped about 5 MPG below 30 degrees, riding the same route every day.

On the CBR, I only lost about 2 MPG below 30 degrees until it stayed consistently below 10 degrees, then it dropped to about 8 MPG

This was stopping at the same gas station and running the same grade of fuel. Now, on the Hawk I DID replace the stock airbox with Uni-Pods but that made no change in the warm vs cool riding mileage. All it did was drop my overall mileage by an average of 3 MPG

[Tipys]

Well at sea level there is more air there and thats where they test the MPG ratings to make them higher numbers if that helps.

[Tipys]

I noticed on the Hawk, which I rode in the winter for 2 years, that I dropped about 5 MPG below 30 degrees, riding the same route every day.

On the CBR, I only lost about 2 MPG below 30 degrees until it stayed consistently below 10 degrees, then it dropped to about 8 MPG

This was stopping at the same gas station and running the same grade of fuel. Now, on the Hawk I DID replace the stock airbox with Uni-Pods but that made no change in the warm vs cool riding mileage. All it did was drop my overall mileage by an average of 3 MPG


Dana you have way to much time on your hands.

[Devaclis]

Nah, I just log almost everything so I can refer back to it, ya know, for reference.