aluminum radiator

I would actually hesitate to say that either of those articles are really strong evidence that copper cools better than aluminium. Simply look at the source of the first article. It's in their best interest that the tests show that copper is better. The second article actually says that they are about equal and that the most important thing is core design. The graph they show compares a four 1/2 in core copper compared to a two 1 1/2 in aluminium.