does MPG go down in the cold?

[live4swell]

Its been freezin here in NY recently and on the last tank of gas i got an etrocious 12.67 mpg...that is the lowest i have ever gotten. I am usually between 14-16 mpg. Plus I know now the gas here has 10% ethanol. But between the cold, ethanol and whatever else comes along with subzero temperatures should mpg go down like that?

 

[RL Lemke]

Generally, when an engine is cold, extra fuel is added to enrich the mixture (eg: the old carb choke). In fuel injected engines, there is an idle increase and different fuel map used until the engine comes up to operational temprature. So, yes when it is really cold your fuel mileage will suck - especially if you let the engine idle to warm the car before you drive off. Ethanol also reduces mileage a bit as it does not have quite the same energy as gasoline. But is does a great job of absorbing the condensation that collects in the bottom of your gas tank though.

 

[mike_d]

yes, in the winter you generally get worse gas milage for a number of reasons:

-ethanol has about 10% less energy than gas for the same volume, so you need burn more ethanol to get the same amount of heat energy that you get from gas

-you generally let your car idle more to warm the engine up, that's a lot of 0 mpg getting averaged in

-the engine runs richer when it's cold

-the oil in the engine, transmission, and differentials is thicker and harder for the engine to turn

-water condenses in the gas tank, so you're also burning water

i've always wondered what the denser cold air does. when it's dense you can get more oxygen into the cylinders, but then it's also thicker for the car to push through.

 

[Larry]

The idea temperature for an engine is very close to the temperature of the combustion chamber but not very practical. If the engine could run at such temperatures there would be less heat lost and more useful power realized.

When you start your engine, you should at least start moving, even if slowly at first. Things warm up better and more evenly, including the transmission and other drive line parts. The engine vibrates less, too.

Engine lubrication is poor when cold, especially cylinder walls and valve gear.

Any time the engine is operating outside ideal conditions you can expect to use more gas for less work.

 

[live4swell]

Thanks for all the info guy, i appreciate it

 

[live4swell]

that was supposed to say guys not guy...haha

 

[EDGE]

I typically have the same mileage this time of year, even the range in both my 4Runner and ES dropped about 20-40mpg which is about right from what I figured over the past years of driving in the cold.

 

[pdonnell]

I've always been curious about what gas saving mod's can be made to the 4.7L 4x4 version of the 4R.
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Everyone likes the idea of K&N's and aftermarket exhaust for performance reasons but what mod's (aftermarket) increase fuel mileage besides a lighter foot?
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I know its asking a lot.:arrow:
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EDGE,
Nice one about the saturn service over at the Lexus site. Do you think most those owners even compared a 4R to their GX prior to purchase? I think some (most?) don't even know it shares the same drive train.

 

[Larry]

The K&N gives up quality for a bit of quantity. You might only see more air flow at higher RPM's.

I'm looking for headers and complete exhaust system. Anyone have any experience with installing an exhaust sytem?

Another thing that might help mileage is tire pressures up around the allowed MAX pressure and synthetic oil.

 

[HiluxSurfBMX]

yes, in the winter you generally get worse gas milage for a number of reasons:

-ethanol has about 10% less energy than gas for the same volume, so you need burn more ethanol to get the same amount of heat energy that you get from gas

-you generally let your car idle more to warm the engine up, that's a lot of 0 mpg getting averaged in

-the engine runs richer when it's cold

-the oil in the engine, transmission, and differentials is thicker and harder for the engine to turn

-water condenses in the gas tank, so you're also burning water

i've always wondered what the denser cold air does. when it's dense you can get more oxygen into the cylinders, but then it's also thicker for the car to push through.

The thicker oil in your transmtion, axles and engine do quite a bit of milage reduction in themselves. 90W gear oil turns almost hard in subzero weather.

Dense, cold air had more oxygen in it. When your engine sucks more oxygen in it it would run lean unless it gives more gas into the mixture.

All good points you've raised as well. Just thought I'd put in my 2 cents.

 

[EDGE]

The thicker oil in your transmtion, axles and engine do quite a bit of milage reduction in themselves. 90W gear oil turns almost hard in subzero weather.

J-E-L-L-O

The reason as to why when it's freezin outsize and I start the truck up the thing does not want to go past 10-15mph

I have been told by several guys who worked on engines that you can cause 300-500 miles of premature wear on an engine by not letting it warm up properly.

 

[EDGE]

EDGE,
Nice one about the saturn service over at the Lexus site. Do you think most those owners even compared a 4R to their GX prior to purchase? I think some (most?) don't even know it shares the same drive train.

Glad you like that, I try to push their buttons every now and then but they make it to easy, the mod JohnyMo is pretty cool and he is way to accepting of some of those guys constantly posting my Lexus is a POS.

I've seen some of your post on that board, nows their is 2 of us:50cal: just don't burn yourself out cause some of those guys can argue about nothin all damn day, makes me laugh when someone say the GX and 4Runner are 2 completly different vehicles:arrow:

 

[aj884runner]

Ggas Mileage

Hey Guys,
Poor gas mileage in colder temps is also due to the engine parts being alot closer together then when it is warm. The tighter tolerances make the engine work harder to do the same as when it is warm, and it is not just because the oil is like molassis! Try turning a engine over by hand when it`s cold, compared to operating temps, WOW!

 

[gaslight]

lets just face it the sub zero temps we have been having for weeks sucks @ss.
Even if I let it warm up a couple of min. the steering and trans are still stiff.

colder air is denser air containing more oxygen in a given space compared to hot air. To burn properly the computer has to add more fuel. More oxygen and more gas = more power. Thats why so many people try to put cold air intakes on their vehicles. Trying to get the cooler air infront of the vehicle not the hot air from behind the radiator.

 

[Highland Runner]

Many states oxygenate gas in the winter causing mileage to go down. This is done to reduce emissions in the winter.