Cold air induction

International large trucks used cold air intake. The L190 & R190 series had an air-box before the air cleaner that either pulled air in from under the hood or pulled outside air in through the side of the hood.

There is definitely an advantage to pulling in outside air than hot under hood air. I'm thinking every modern vehicle pulls outside air. Muscle cars of the 60's used scoops either direct or cowl, they both brought in cooler air and had a slight pressurization at speed.

Will you notice the difference by adding a cold air intake, I would guess probably not, but there should be an advantage even if it is slight.

Tad

On the heavy trucks with carb'd engines they had an intake from around the grill, but they also had a manual diverter (cable operated) to take warm air. My Fleetstar is this way. In hot weather, while working hard, cool air was used but in cool weather the warm air is needed for good vaporazation and to prevent carb ice which can choke the intake to the point the engine will not run.
In Canada and Alaska even diesels take warm air from under the hood.
By the time in autos where they made the intake thermostaticly controlled (automatic) the large truck gasoline and LP engines were being phased out.