Originally Posted by old man neri

I think everyone aggrees that there will be no noticible difference as long as you don't clog the passages and as long as your coating is very thin. So paint if you want to be lazy with something thin or anodize it if you want a good job


Now for the science arguing which plays really no role in this problem:

Denser materials are not used for heat diffusion. First of all what type of heat diffusion are you talking about? radiation, convection, or conduction. All three always play a role. for radiation generally someone black in colour will radiate heat better. For conduction something with the best heat transfer coefficient will conduct heat the best, not the most dense. (Al is used in a lot fo heat sicks cuase it's quite good and light, copper is actually better but is heavier. Gold and platinum are the best but a bit pricy and very heavy) and for convection well, usually we use air cause we don't have a choice, there you are playing with the airflow to maximize the forced convection.

And of course aluminum is anodized as opposed to painted black on a heat sink in my comp. anodizing is much better then painting alumninum. This was my suggestion from the get go. But painting is simpler to do at home that's why it is also another suggestion.

Here is where it all comes in to play. Let us just neglect radiation cause i doubt it really plays that much of a role. Hot air flows through the intercooler, it makes the fins hot. the hot fins transfer heat/energy to the air. We all know this. A measure of performance could either be how cold you get your outlet air to be or how many watts did the intercooler to be. Seeing as the intake air will always be the same temp the two ways of measure are indeed relative to each other. Now if you coat the intercooler/fins with either paint or anodizing (yes i know they are different process and made up of different material but just go with me on this for a sec before you flame) you now have to have conduction between the aluminum and the paint and then convection from the paint to the air.

Let us assume there is no contract thermal resitance. So now the only hinderance is that the paint/anodization layer is not conduction heat as well as the aluminum. But the whole point of it is that the layer is so so small that there is still almost no termperature changer. Then the it convects to the air. The convection is based on a few things. an "h" factor and the temperature difference. the "h" factor depends on air flow, the material (air in this case). The airflow will not really chance (yes it will slightly change because the fin stapcing all of a sudden decreased by a few thousands and the surface texture will slightly altered but it will not significantly change.


Heat disapaited = "h" X (diff in temp between air and surface of intercooler) X area

now, if "h" doesn't change, neither does the area, and the temp difference is ever so slight then the amount of heat dissapaited (in watts, or horespower, or whatever) won't be significantly affected.

This is compounded by the fact that even if there is a huge change in termperature at your outlet (coated vs not coated) such as half a degree it still won't affect. So in conclusion giving it a light coat of paint or anodizing it will make no real difference, just like the tests show.

you will get better perfomance gain if you race naked and save on wieght.


So to answer your comment, yes i do know what i am talking about.......
Positivly worded questions or comments are welcome (i.e. do swear at me)