The great intake debate!

[HTM Yaris]

I say the primary function is shared .

In a cold air system there isn't any "box" or baffles to help muffle or deflect (maybe redirect is the proper term) the sound waves coming from the engine . Actually the exhaust and intake work almost identically , with the exception of the temps and flow direction . Take off your muffler and what happens ..... That's right... it gets louder . Same with the intake box . CAI are designed to increase flow . Sure your filter may be away from the engine or even shielded from the engine , but the actual intake tube is still being heated by means of convection (air flowing through radiator ) and conduction ( you know , those explosions that are generated in the cylinders ) not to mention friction . A true CAI would address all heat issues . A refrigerated wrap around ( the intake tube ) blanket comes to mind .

As for emissions , that's easy . Add more air (CAI) and the ecu will compensate by adding more fuel . Which in turn means more pollution . A turbocharger or supercharger is a perfect (extreme) example of this . Yes I understand that a Turbo or SC forces air into the engine , but my point is more air = more exhaust . Keep in mind , any engine , is nothing but an air pump with accessories attached .