With all the talk about intakes, CAI vs. HAI etc., I was just wondering if, technically speaking, one would be able to achieve better MPG in the winter than the summer. I ask this because of all the constant attempts to keep the engine bay as cool as possible and the talk about making sure cool air gets into the intake. Also, I've read that cold air is richer than hot air. So, does the fact that cold weather naturally brings with it cold air help MPG? Or, does it not really matter since the engine bay is going to get hot regardless?

 

I'd say it helps.

In the heat, the ECU will pull timing and dump fuel to compensate and prevent detonation. In the winter, this is not the case due to the cooler temps. I'd think it counts for a little better mileage...

 

and if you are in CAL (not sure of other states)
the summer blend of gas does not give as good mileage

 

All I know is the butt dyno tells me I get more power in cool night or winter air... usually that means more efficiency which = better MPG. How much, I don't know.

 

My MPGs always drop 2-3 mpg in the winter. Combination of a cold engine taking time to come up to operating temperature and the different gas mixture we get in the winter. I guess if you are talking about a California winter (is there such a thing? ), you might get better mileage.

 

cold air FTW =] im getting crazy mileage =]

 

Yes it is cold here in california in the winter. last week i had to put a long sleave shirt on at night and i almost had to wear pants instead of shorts, BRRRRR

 

i live in northern cali and during the winter i notice my mpg drop a pretty large amount. im guessing since the air is cooler its much more dense therefore i need more fuel to keep my a/f ratio intact

 

My understanding is that colder air yields more horsepower but less fuel mileage.

 

Cold air is denser than warm air... hence the additional power/economy depending on your right foot...

Here in Illinois the thought of getting better MPG in the winter is a joke because the dense air is offset by warming the car, the winter gas blend let alone anything like stop and go traffic in 1" of snow...