Would the Prius get better milage if it had a cold air intake on it?

It has a cold air intake. Some folks are of the opinion that warming the air in the winter improves mileage. However, this remains something still under discussion.

Recently, I developed a technique for measuring gasoline energy content but testing at 60F and 88F has not shown a significant change in ICE efficiency within the same tank. When the colder weather comes back, I'll re-run the tests with a wider temperature range.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

cold air intake is often a misnomer. they are very simply an exposed filter on a tube and may or may not provide cooler air entering the MAF sensor. on a prius they would be a waste of money i would think. i'm sure the prius engineers designed a very efficient airbox for your small displacement engine. keep your filter clean or throw in a k&n if it makes you happy. it will last the lifetime of your car (but require a re-oil every ~50K miles or so)

I agree. Cold air intakes are designed to add more oxygen, and create more horsepower, burning MORE GAS in the process.

Liquid gasoline does not burn. Only gasoline vapors burn. The colder the air/gas mixture, the more difficult it is vaporize to ignite, and you risk loosing more gas unburned out the exhaust.

A WARMER air intake is going to be a more fuel efficient one.
-John

actually, no. a cooler charge makes more hp and is more efficient. why do you think turbocharged engines are intercooled...
cooler air makes for better combustion (up to a point) & lower intake temps enable the engine to advance timing - hotter cylinder temps lead to predetonation/knock. if the cylinder temps are too high the engine ecu will compensate by making a richer mix in order to cool things down (more gas used). again, turbocharged engines will see this on a greater scale, but the same principle applies to NA engines as far as i know.

Lowering the resistance between the throttle plate and the outside won't change the part throttle fuel economy on a modern spark ignition car.In part throttle operation Any drop in resistance upstream is simply countered by closing the throttle plate;any increase in resistance is countered by opening it a little until the amount of mixture is what is required to pull the load.
In the sort of driving most folks do on this forum, you could tape about 20% of the air horn off,and you wouldn't be able to measure any change in FE.
CAIs might improve peak hp(the ones commonly sold probably drop hp at many RPMs), but they won't improve FE on a modern car.
Luck,
Charlie

Sorry Pete. Everything you said goes against chemistry and physics.
I already said cold air intake systems provide more horsepower.
This is at a cost of more fuel being burned.
Any cold air intake is NOT designed for fuel economy.
Don't take my word for it, and please don't argue with me and tell me I'm wrong. Go out and try it.