Painting intercoolers

[Draven]

the noticable performance difference from the above "light mist" should be precisely fuckall... but if you happen to know someone who annodises cheaply, do that

[oldcorollas]

some good answers here

for stealth, if you only want to paint the front 5mm (and make sure you don't get it anywhere else.. perhaps submerge all but the top 5mm in water, then spray... no overspray?

paint is usualy a polymer binder, with either ceramic or (maybe?) polymer pigments...

anodising is ceramic.. but is only in the thickenss of microns... paint is in 10's of microns

anyone feel like calculating the heat transfer change (use Gaskells book for equations)

[ed]

ok - can the folks who want to argue against the laws of physics please go use the search function then hit google...

[kingmick]

paint? that will just insulate it!!

if you want black (which IS far more thermodynamically effective for a cooler) then you should buy a black annodised one

painting is a silly idea

yes. the right black paint works as does anodising which isnt that expensive. around 22 pieces some small some very big sheets of alloy cost ,me around $400.
there car companies spend billions painting them black, not just for looks.
racing we dont pant them but we oversize so dont need to.
this has been covered a huge amount in the old forums. there are two trains of thoughts to it as have been shown here to extreems of both.
i have seen neither for or against in practical terms, exept if you have a front mount and its in direct sunlight it will draw more heat.
it is one of those areas that there is for and against with both!
but that said, any paint that happens to be at hand will not do the same job as the one tried and tested
i have yet to find anything to prove either!


sorry for typos and grammar!

[4agte]

what does toyota use to cover its intercoolers in? the aw11 s/c intercooler is painted black altho it dosent do the best job of cooling but thats probably got more to do with its location rather than the paint..

[Bananaman]

Surely its safe to say that whatever effects there are, are not worth worrying about in anything other than the highest standard of application? That is, not worth worrying about in your typical street car?

[kingmick]

flat black and never enamel.
ive yet to see an anodised cooler or radiator in a racecar! I do the piston skirts and alloy interious{easy to keep clean and looks good}.

I think its one of those things that has never been proved one way or another! might be a great myth busters one. But they might get it wrong

[HAVABEER]

will the effects of having the paint on the intercooler really be insanely noticeable? loss of like half a horsepower or will it actually be considerably felt?

[oldcorollas]

flat black and never enamel.
ive yet to see an anodised cooler or radiator in a racecar! I do the piston skirts and alloy interious{easy to keep clean and looks good}.

I think its one of those things that has never been proved one way or another! might be a great myth busters one. But they might get it wrong

if someone wants to borrow this book from a llibrary and send me some pictures of pages, i'll prove it one way or another. the flux of heat, for a given temperature differential can be easily calculated. the thickness of anodising and paint is known, and their heat transfer properties are also known.
http://my.linkbaton.com/isbn/0023407204
david.R.gaskell, an introduction to transport phenomena in materials

i would suggest that the reason you don't see radiators and IC's anodised is because it is (for want of a better word) an electrical process, where distance between the anoe and cathode determines the thickness of oxide.... with a complex shaped part, you will not be able to get a consistent oxide film thickness.

you could however bake it to form a thicker oxide layer

[oldcorollas]

from here http://www.hardcoatingsinc.com/rfq.html

How thick is anodizing?

Typical thickness of clear and color anodizing is 0.0002" to 0.0005". Black ranges from 0.0005" to 0.0010". The standard thickness for hardcoat anodizing is 0.002".

so anodising gives a porous oxide layer (honeycomb structure) of between 5 and 25 microns thick.

from here http://electrochem.cwru.edu/ed/encyc...-anodizing.htm


from here http://www.ase4anodising.co.uk/Hard.htm

4. THERMAL PROPERTIES
The thermal conductivity of the anodic coating is between one tenth and one thirtieth of that of aluminium. The emissivity of aluminium increases rapidly as the thickness of the anodic layer is built up increasing to 80% for a 10 micron coating. A thick hard anodic coating is therefore well on the way to being a "black body" for heat dissipation, and there is very little advantage in dying it black as is sometimes done.

interesting..

aluminium thermal conductivity is 235W/mK
alumina thermal conductivity is 18W/mK

somebody wanna find data for paint?

and if you ever wanted to know data abotu emissivity of different finishes.. http://www.tak2000.com/data/finish.htm

[ed]

nerd

10 char

[CLG]

Yep, I'll be painting the front of mine more as deterrent for both boy racers and constabulary alike. Ed, you can whinge to me after you reply to my email - hehehe!

[Toobs]

Emissivity data for paint: http://www.electro-optical.com/bb_ra...tlemisivty.htm

From what I recall of previous readings of thermal dynamics is that emissivity is a variable denoting the ability of a surface to absorb energy... there is another law which states something along the lines of an objects ability to absorb energy from outside is equal to it's ability to radiate energy from within.

With regards to heatsinks and radiators etc. the summary is that to create the most efficient heatsink (i.e. one at perfect equilibrium) you need to select a material with an emissivity equal to the ratio of internally vs externally generated heat.
e.g.. if 90% of the thermal energy is contained / generated inside the intercooler and only 10% is contained outside then a thermal material with an emissivity of 0.9 would put the system at equilibrium.

these laws are generally applied to systems which generate a constant amount of heat on either side of the system though and thus this is the only way to properly bring them into equilibrium.
When your talking about intercoolers on cars if say had an IC with an emissivity that is greater than the ratio of absorbtion vs reflection... to bring the system into equilibrium you could either reduce the emissivity of the IC or increase the thermal energy generated inside the IC.

translation: if your IC is more efficient than necessary the laws of thermaldynamics state that unless you want to be robbed of power by external sources you must either reduce the size / efficiency of your IC or increase the boost.

Hmm... I wonder if the defect squad would accept that as a valid arguement for boosting your car.
Surely they wouldn't argue with the laws of physics!

[Vios-GT_07]

my take is this : you can't buy painted intercoolers from big aftermarket companies... never seen a Greedy or HKS intercooler that is other than aluminium and not painted.. if they don't paint it, must be for a reason..

oh those ones that have words in front, i notice only the fins / plate are painted.. and it's a very small area.. so it'd make fuck-all difference IMO.. hm..

edit : shitzzz.. just realised i missed out half of page 2...

[ed]

never seen a Greedy or HKS intercooler that is other than aluminium and not painted.. if they don't paint it, must be for a reason.. .

um, bling = $$ in their pocket

why buy an intercooler if your habibs cant see it?
thats almost like buying fake intercooler mesh and spraying it black...