Not sure where to post this but.... Can someone tell me what the difference is between a air intake and cold air intake on a diesel please?

 

A CAI takes "cold" air from outside the engine bay, where as a AI just takes "hot" air from inside the engine bay.

The cooler the air intake temps are, the more dense the air, this is good for atomization of fuel and air for the combustion process. Theoretically the cooler the air coming in the intake the cooler it will be after is is compressed and sent through the intercooler to the plenum.

 

Ok so is this a cold air? I have something like this but it's just a air intake but this guy keeps telling me its a cold air?

 

most "cold are intakes" are mislabeled and actually still pull air from the engine bay as the one you posted.

the real ones will typically pull from the wheel well which may require cutting some sheet metal.