As previously said, black absorbs heat quicker, but also releases heat quicker.

To me, painting it black would simply eccentuate the conditions the intercooler operates in. Silver would operate in more stable condition e.g less fluctuation is air temps.

Furthermore, if your air temps are stable, then whether your intercooler is black, pink, white, shit brown or rainbow it isn't going to make a difference. The colour will only effect the rate of heat loss as well as heat gain.

I guess the reason why intercoolers are predominatly silver/reflective etc, is because the air around them in generally always hotter (aka ontop of the engine) than the air inside the intercooler. It is desireable to restrict this heat as best possible so silver will reflect better/absorb less of that heat.

Hence the reason why radiators are black. The temperature of coolant inside the radiator is generally a lot hotter than the air surrounding it. In this situation the heat will dissipate faster from the radiator which is advantageous.

From a logically point of view there isn't many circumstances where the temp outside the intercooler is going to be colder than the temp inside the cooler. This is the only time where a black would be of more advantage than silver.

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