What properties should the connection tubing in a car radiator have? (Note that the tubing is not the fins). Here is a video of the connection tubing
the only properties a tube should have is good heat transfer to the fins... The fins actually pull heat away from the tube and the air passing over them is how it cools the coolant in the radiator. The more fins per inch the better the cooling ability of a radiator... this is if I understand your question correctly
