Mighty Car Mods Black Intercooler Counterargument

[mixmasterlooney]

The better part of an argument explained with evidence and science. I have been critical about the black painted intercooler myself but here is everything you need to know

http://youtu.be/z_mmmXTbLP0

One of the youtube commenters said the following, rather interesting.

"It's not all about power, turbocharged cars are very fuel efficient. A smaller motor can make the power of a big motor, but only when needed. Sitting at idle or low speed with a lower intake temp is a benefit for my fuel economy, as my engine can use even less fuel to maintain enough power to idle. Also, in a drag race, staging (vrooom popopopopopop) a turbo car can see benefits on the line from a cooler intake temp. Just depends, clearly there are advantages and disadvantages to this mod. Decide for yourself what your car might need"

In reply from EE

"I think you slightly missed the intentions of my video. Let me clarify: A car doesn't need to cool the intake charge when not moving. There's either a vacuum (and thus no temp increase from compression), or any benefit of radiation will be diminished upon accelerating"

[FOCA]

Both MCM and the youtube reply have errors (and make assumtions)

The MCM test is done without being fitted to a car, and not done in "real life" conditions (eg- like with the heat from the engine bay/ radiator, etc, or the heat from a real turbo etc) - so it does not take important factors into account (its a very simple test)

A regular intercooler on a road car does not have a fan, the radiator fan only comes on at high temperatures, so if the intercooler has no air running through it (when the car is static or moving at very low speed) the black painted intercooler will radiate more efficiently

BUT, a black painted intercooler will absorb more heat (heatsoak) from the radiator (because it works both ways)

so the best thing is to have the FRONT of the intercooler painted black, and the back shiny silver - so it radiates heat better when the car is static, but reflects heat off the intercooler from the cars radiator and the underbonnet heat

The black front/ silver rear is my idea

You could also put extra fans in-between the intercooler and radiator, and move them apart (not my idea- ive seen it on race cars) this would make the airflow through the intercooler and put a phisical (insulating) barrior between the radiator/ intercooler

You could also fit a waterspray to the outside of the intercooler (seen it on a EVO on TOP GEAR years ago- originally used in racing/ rallying) - ive got one on my Mondeo - it really works - (its to do with the latent heat of evaporation and the (exellent heat)absorbency of water )

The MCM test showed a sight decrease

in efficiency when air was flowing through the radiator (probably due to the insulation effect of the paint) but the effect was only slight, and as the increase when there was no airflow (when car was stationary/ not fitted with an intercooler fan) was a significant improvement

A drag racing car has to wait on the line, a race car has to as well, and a road car is often stationary in traffic etc - so its worth painting your intercooler black (or the front of it) if you dont have intercooler fan(s)

[mixmasterlooney]

I see your point about when the car is not moving however that's when it doesn't matter how cool the air is although cooler air does result in better efficiency at idle rpm it wont make any difference to performance.

Even if only the front is painted black this will still reduce airflow and increase the cooler ambient temperature when exposed to the sun or other heat sources whilst moving where the performance is needed.

With drag cars i see your point and that may well benefit drag cars on a road car though after viewing both sides of the argument i don't think it's worth painting it black (With or without a fan) That extra layer of black paint that attracts heat just doesn't add up over the stock cooler in my opinion.

[troy45]

I'm going for a variation on the black/silver option.

It's a Pro-alloy MT260 intercooler, originally painted black but it's gradually turning silver as the paint falls off it :)

[FOCA]

I see your point about when the car is not moving however that's when it doesn't matter how cool the air is although cooler air does result in better efficiency at idle rpm it wont make any difference to performance.

Even if only the front is painted black this will still reduce airflow and increase the cooler ambient temperature when exposed to the sun or other heat sources whilst moving where the performance is needed.

With drag cars i see your point and that may well benefit drag cars on a road car though after viewing both sides of the argument i don't think it's worth painting it black (With or without a fan) That extra layer of black paint that attracts heat just doesn't add up over the stock cooler in my opinion.

This is a complex subject, and if its over-simplified some important points are missed out

In the MCM test, the black paint only had a slight effect in insulating the intercooler from the cooling air when the air (car) is moving (assuming no intercooler fan(s) are fitted)

but, when the car is not moving, the back paint helped the intercooler radiate heat far more efficiently

So, (according to the MCM test) using the black paint had a very slight disadvantage with air flowing through the intercooler, but a big advantage when the air(car) is static - in my view, this big advantage outweighs the small disadvantage / so its worth painting the FRONT of the intercooler black

On my car the intercooler is almost never exposed to direct sunlight, the intercooler is tucked under the protruding bumper and also behind horizontal slats - this is true of most Fords

The heat from the cars radiator and engine bay (heatsoak) is a far more serious consideration than direct sunlight (MCM overlooked this)- this is why i recommend only painting the front of the intercooler and not the back, otherwise the black paint will absorb more heat (the black paint works both ways)

When the car is being driven, it can be going at different speeds and be static a lot of the time, (depending on conditions) - if the black paint helps the intercooler stay cooler when the car is static, it will result in overall lower temperatures when the car does move

There is a thing called thermal inertia - this basically means a large mass of metal takes longer to heat up than a smaller mass of metal but it takes longer to cool down

So a larger intercooler (large mass/ high thermal inertia) will take longer to heat up (thats good) - it will take absorb more heat/ take more energy to heat up, and stay cooler, unfortunately it takes longer to cool down once it gets hot (thats bad)

A smaller intercooler (small mass) may heat up quicker (bad) but looses heat quicker too (good) - it has a low thermal inertia

if the black paint on the front of the intercooler helps the intercooler stay cooler when static it will help the intercooler achieve overall lower temperatures (more efficiency/ power/ economy) when the car is moving too (due to thermal inertia) - eg - the intercooler starts cooler/ stays cooler