I've always been a fan of the mat black intercooler just for subtlety. Like L18_B110 said it doesn't make a bee's dick of a difference until you start putting thick layers of paint on the core and actually start insulating the compressed air inside it.

As was mentioned earlier, the colour of the surface only has an effect on radiant heat. Radiant heat is a function of some constant of radiation, the surface area and the temperature difference between the surface of the material and ambient temp. As you can imagine the surface of the intercooler will barely rise above ambient making radiation negligible.

I would like to test out a few intercoolers myths, mythbusters style, could be interesting.

all this shiny/polished surfaces retain/reflect heat and matt black surfaces emitt heat is only relevant to radiation of heat. intercoolers do not work on this method of transferring heat.

intercoolers use convection. the surface colour could be pink and it won't affect the way the intercooler transfers heat.

rocker covers and engine blocks on the other hand only have radiation to use to transfer heat and matt black is the go for them.

We really are splitting poofteenths here,intercoolers as you say use convection,but anything painted a dark colour will absorb and retain more heat from outside sources than if the same item where painted a light colour.The thicker the paint colour is added will not effect temperature,six coats of black paint will carry the same temp.as one coat over a measured time.

This is all a bit hard is'nt it? Shiny is good i reckon

(we did paint chemistry in the old days at trade school)

it does make a difference, my mates wrx, tested it, with few temp probes, i can't remember which setup he had at the time, top mount or front mount?. xr6 turbo are black, F6 typhoon are mill finish. i have noticed that top mount Gtir are mill as well.

Pink? Now there's one colour you wouldn't want to paint it, it will immediately get so hot it'll spontaneously combust an disappear in a cloud of Fanta bubbles...

if you're realyl obsessed with the look and performance of the intercooler than anodising it could be you answer. It's worth having a bit of a google at

ok fords new xr6 ba bf you can have the fmic in matt black or alloy thats wat got me thinking .
and lots of people saying black will absorb heat conpaired to alloy well maybe in the sunlight ? but black cools down the fastest ?
and thats the hole idear behind a intercooler ?

its high school physics. there are 3 types of heat transfer:

1) conduction - either through solid materials or different things in direct contact. ie intercooler and air. only surface treatments that help the even distribution of heat can help here. black paint doesn't do that and won't help the intercoolers efficiency. the colour of the surface is irrelevant to the conduction of heat. It depends on the thermal conductive properties of the substances involved - ie alloy and air. air is quite a poor thermal conductor, alloys are generally very good.

2) convection - heat transfer through liquids (includes gasses). while convection currents don't come into play in intercoolers, forced convection does. air is forced around the intercoolers internal and external surfaces to transfer heat. forced convection increases the efficiency of air as a thermal conductor. surface colour has no impact on convection or forced convection.

3) radiation - heat energy given off by a body via particles transmitted away from it. This would only be relevant to the operation of an intercooler if the car was sitting still. or if the intercooler was fitted in a box out of direct contact with airflow. ie its not relevant. surface properties that affect heat emissivity (ie matt black vs polished surfaces) effect this type of heat transfer.

if you still don't believe me, ask yourself why a water spray helps intercooler efficiency. clue - it has 23 times the thermal conductivity of air. And the evaporation and forced convection also provide a cooling effect. does nothing for radiation though. but air to air intercoolers don't rely on that method of heat transfer to work. they need airflow for the forced convection principle due to air's poor thermal conductivity.

lol maybe im a bit thick but thats seems very clever but im more confused now lol
so when the car is sitting at the lights black is better but other than that black does not help heat lose ?
any way sound like there fu*% all in it ill leave it alloy :)

A nice spot of theory there L18, reminds me of my old thermodynamics teacher!

Just in addition to the water spray stuff, the main reason the water spray works is the same reason water injection works. It's all about the heat drawn out of the surroundings by the water as it changes state from a liquid to a gas. Sure water does have a higher conductivity than air but the water on the core is still just in contact with air so still has the same convection issues.

As I'm sure you know it takes a proportionally huge amount of heat to get a liquid to change state to a gas.