Originally Posted by ala_xfire

The larger volume of air you move through the intake, the more you will overcome the engine heat soak on the plumbing.
At 140, you would probably be within 4-5 degrees above ambient .....

I tried an experiment yesterday : I boxed in the air filter in front of the radiator with cardboard to ensure it wasn't sucking heated air from the face of the radiator. I drove 30 or so miles and saw absolutely NO difference in the ambient / IAT ratio than without the cardboard dam.
This tells me that ambient air is indeed entering the system, but the plumbing ( single NW CAI in my case ) is heating it up between the air filter and the IAT sensor. ( I removed the cardboard )