Huh?? If engines like hot air so much why do most cold air intake kits relocate the air box away from the very hot engine compartment into a wheel well instead so cooler air can be sucked into the air filter. Cooler air is denser air (more oxygen) which results in more efficient burning of the fuel. More efficient burning of fuel means less fuel is needed to achieve the same horsepower. This is why most CAI kit manufactures mention increased mpg as a benefit. Check the link below

What Are The Best Cold Air Intakes? How Air Intake Systems Work - Performance Benefits & Install Tips

 

Cold air intakes bring cooler and thus denser air in. This requires more gas to achieve the right mixture.

The only mpg gains from a CAI are placebo effects, or lies.

 

Do you have papers or some sort of research to back up yor claims?

 

If you google "hot air intake" you'll find lots on the subject.

Alternatively, you can prove it just from knowledge on how engines work. Your first claim is that a CAI brings in cooler air, which allows the engine to make more power. Anyone who's ever driven a vehicle in 100 degree summers and then hit 50-60s in the winter knows that this is true. This is because cold air is denser, there is more O2 in the air that the intake pulls in, which means to keep the ideal stoicheiometric ratio, the ECU pumps more gas in with each squirt. Clearly, this will result in more gasoline useage, as more air more gas = more power = lower fuel economy. On the other hand, if you bring in hot air, it is less dense, thus less O2 to use in combustion, and less fuel is needed to be injected each cycle.

So going from what we know about engines, you can CLEARLY see that there is no way for an intake to increase performance and fuel economy by bringing in cold air. The only way to increase this is to adjust the efficiency of the engine, which can be done with an ECU tune, and in some cases (not as common in modern times) an exhaust. The CAI are just feeding you a line of marketing, if an auto manufacturer could gain fuel economy AND performance (especially in today's times where everyone wants to be eco friendly so long as their midsize sedan runs 14s) just by swapping out the filter and piping, don't you think that they would do it? Even if the oiled filters were less effective, surely an automaker with as many engineers and resources as they have could have found a better alternative than just paper and bested all their other competition with superior intakes.

 

This thread got highjacked but anyway here is my 2 cents

You forgot one member of the equation ... The Driver and his target speed.

Cold air = more O2 = use more fuel = more HP = Driver press less on pedal for a given speed = better fuel economy.

My training is Aviation, where in the old days of Piston engine the pilot had control over every thing going in the engine.

Carburetor heat to avoid freezing meant lower power and an increase of fuel consumption because to maintain speed you need to push the throttle a little more. Worst engine efficiency but no freezing.

Built from the factory car have automatic carburetor (or throttle housing) heat.
This is what you are bypassing with a CAI setup and yes you run the risk of icing when the condition of cold and humidity are right. A venturi is a cooling machine in the narrow section the air accelerate but drop in temperature (thermodynamic principle)

Colder air mean more HP and less throttle thus better fuel economy at a give load. Better engine efficiency.
Warmer air mean less HP and more throttle thus worst fuel economy at a give load. Worst engine efficiency

And I did not include the humidity of the air in the picture.

Remember, we are maintaining speed (or load on the engine).

 

That was my point. All other things being equal cooler air results in more efficient combustion which in turn uses less fuel. Of course if you drive more aggressive after installing a CAI your mpg is going to go down.