Has anyone else seen this, I'm completely amazed that some black paint can make that much difference.
I can't see why this wouldn't work on the radiator as well, if it really works that well it would be handy the next time I get stuck in
traffic lol
https://www.youtube.com/watch?v=f1QL9veQaNg
Seems pointless to me, the key point is that intercoolers and rads (slightly less so in rads) are only any use when airflow is present.
The idea of an intercooler is to add power, but who wants more power when your not moving?!
For rads, whilst it might help reduce when the fan kicks in when in traffic, but the moment the fan blows the benefit is lost.
[Edited on 17-6-14 by loggyboy]
Ermm...Anyone who has done O level Physics should know black is best for temperature transfer.
Just try wearing a black shirt (or ride a motorbike in full leathers ) on a sunny day.
quote:
Originally posted by loggyboy
Seems pointless to me, the key point is that intercoolers and rads (slightly less so in rads) are only any use when airflow is present.
The idea of an intercooler is to add power, but who wants more power when your not moving?!
For rads, whilst it might help reduce when the fan kicks in when in traffic, but the moment the fan blows the benefit is lost.
[Edited on 17-6-14 by loggyboy]
The way im looking at it is, you might be better recovery times from this because its not getting as hot at slower speeds where the air flow is minimal ?
Black body radiation is pretty well understood ( http://en.wikipedia.org/wiki/Black-body_radiation ), so throwing some numbers at this:
110deg C radiator temperature
25deg C ambient temperature
Radiator area 0.25 sqm (i.e. 0.5m x 0.5m)
sigma 5.67x10^-8
Power = (T1^4 - T2^4) * Area * sigma
Gives you a net power dissipation from a radiator being "perfectly" black as 200W.
Think how long a kettle would take to boil if it were 200W (they are normally 3000W).
Radiation is not a significant mechanism. Paint it if it make you happy, but I think the paint will just add an additional layer of insulation to the
air which is conducting the heat away (the dominant cooling mechanism).
For an intercooler the effect will be smaller still owing to the lower temperatures.
Matt
quote:
Originally posted by NigeEss
Ermm...Anyone who has done O level Physics should know black is best for temperature transfer.
Just try wearing a black shirt (or ride a motorbike in full leathers ) on a sunny day.
You'd have to make sure the sunlight couldn't hit it or you'd have the opposite effect on a sunny day.
OK here's a field where I can step in with some experience...
Black paint will help significantly if radiation is the ONLY heat transfer mechanism you have(i.e. zero airflow as they show). The second you add
forced convection to the mix, or conduction, you essentially negate the radiation component. Black paint does indeed help radiate heat faster to the
environment, but it also provides a thermal barrier between fins and air. At zero airflow you MAY see an increase in transfer (you may not, depends on
the the paint used, the previous condition of the rad surface and the thickness of the paint) but above zero air speed you're better off with no
barrier between the surfaces.
Since intercoolers are generally designed to work when moving, all this will do is increase the time to heatsoak when stopped, which for most driving
isn't an issue.
Not worth the effort.
black paint will add extra layer of insulation, although as to how effective/ineffective is a moot point, should be black anodised or chemically blackened imho
Black anodising adds insulation too, about the same thickness.
quote:
Originally posted by coyoteboy
Black anodising adds insulation too, about the same thickness.
lol
quote:
Originally posted by matt_gsxr
Black body radiation is pretty well understood ( http://en.wikipedia.org/wiki/Black-body_radiation ), so throwing some numbers at this:
110deg C radiator temperature
25deg C ambient temperature
Radiator area 0.25 sqm (i.e. 0.5m x 0.5m)
sigma 5.67x10^-8
Power = (T1^4 - T2^4) * Area * sigma
Gives you a net power dissipation from a radiator being "perfectly" black as 200W.
Think how long a kettle would take to boil if it were 200W (they are normally 3000W).
Radiation is not a significant mechanism. Paint it if it make you happy, but I think the paint will just add an additional layer of insulation to the air which is conducting the heat away (the dominant cooling mechanism).
For an intercooler the effect will be smaller still owing to the lower temperatures.
Matt
Alsi, I think I would be more concerned with the paint thickness restricting the airflow than how much it insulates.
I believe the Garrett website suggests you can paint an intercooler black with 'no significant disadvantage' for that stealth look...no mention of any advantage
There is lots of interesting reply's on this
screenshots from the video
With air flow, no real improvement
With no air flow, quite a dramatic change
I properly wouldn't do this on my kit car but I think on the Sierra Cosworth I had it would be interesting to see if there was any real world
difference
Why is the painted one worse when there is airflow?
quote:
Originally posted by smart51
Why is the painted one worse when there is airflow?
quote:
Originally posted by Digimon
quote:
Originally posted by smart51
Why is the painted one worse when there is airflow?
Its 3 degrees cooler
The seconded photo is also unclear, it shows much temperature has been taken off the temperature entering the cooler
So if I'm doing a burnout then a black intercooler is best. Nice.
quote:
Originally posted by smart51
It's 3 degrees less temperature drop isn't it?
quote:
Originally posted by Benzine
So if I'm doing a burnout then a black intercooler is best. Nice.
No, it's 3 degrees LESS temperature drop across the intercooler (i.e. first one was 100 (200(in)in-100(out) = 100(delta)), black one was 97
(200(in)-103(out)=97(delta)). It's the insulating effect of the paint (if their measurements are half decent - though I wouldn't exactly
call that a scientifically repeatable setup).
It's no myth, it's a set of well understood, well researched, well documented (and taught at engineering classes across the world) features.
As said at the start, painting it black will help when there's no airflow (when radiation is dominant), when it's got airflow the paint will
be a thermal barrier and it'll be LESS efficient. Since most of the time you're moving, you DONT want to paint your IC.
[Edited on 17/6/14 by coyoteboy]
[Edited on 17/6/14 by coyoteboy]
quote:
Originally posted by coyoteboy
No, it's 3 degrees LESS temperature drop across the intercooler (i.e. first one was 100 (200(in)in-100(out) = 100(delta)), black one was 97 (200(in)-103(out)=97(delta)). It's the insulating effect of the paint (if their measurements are half decent - though I wouldn't exactly call that a scientifically repeatable setup).
It's no myth, it's a set of well understood, well researched, well documented (and taught at engineering classes across the world) features. As said at the start, painting it black will help when there's no airflow (when radiation is dominant), when it's got airflow the paint will be a thermal barrier and it'll be LESS efficient. Since most of the time you're moving, you DONT want to paint your IC.
quote:
Originally posted by Benzine
So if I'm doing a burnout then a black intercooler is best. Nice.
coyoteboy got it spot on.
in fact, it has been shown that having a matt surface is nearly as significant as the colour when heat transfer by radiation is concerned.
bascially it ain't worth doing for a radiator/intercooler that is using forced air through it for cooling..... but should make a difference for
your central heating radiators if the matt balck fits in with the decor.
[Edited on 19/6/14 by 02GF74]
If you're concerned with heat transfer then buy some 'Water Wetter' - seems to make water wetter than it normally is which aids
cooling. Used a lot on race bikes where other additives like anti-freeze aren't allowed. Obviously not much good on an intercooler 