Does painting your inter-cooler black make it more efficient?

[BigO]

So I was on Youtube today and the new Mighty Car Mods video popped up, interestingly enough it is a myth-busting video regarding how painting your intercooler black affects its ability to cool air efficiently.
There's two sides of the debate here, one of which I have never heard before. The first is that the insulating properties of paint will reduce the ability for the IC to cool.
The second is a concept that I find really interesting(and haven't heard of, although it makes sense), Black objects can radiate heat more efficiently.

Take a minute and watch the video and prepare to have your mind blown.
https://www.youtube.com/watch?v=f1QL9veQaNg#t=207

I find this extremely surprising as I have never heard anyone defend the idea that painting your IC is a good idea. I personally have mine painted fairly thickly with gloss black and I do not notice a difference in BATs.

What are everyone's thought's after seeing this video?

[jm211]

It makes sense. Most notable is that most of the time is not spent idling, so there are no savings to be had. An argument could be made for running the 1/4 mile/autox as you spent much of your time waiting in line.

I would be interested to see it on a car before/after. Fmic are noted for shedding heat soak quickly. The big question is how much quicker will the black become "un heat soaked" vs the silver intercooler once you begin moving.

Heat, acceleration, speed, etc. Would all need to be considered, I imagine.


Paint is not a very good insulator, also.

[beachshoer]

Yeah the findings surprised me for sure. The question is now..... Will silver FMICs be considered rice since black is more efficient and silver is for looks????

[outshined]

Black-body radiation - Wikipedia, the free encyclopedia

[FSUMazdaSpeed]

Wow I'm shocked, installing my FMIC once my piping arrives, now I have to debate whether I want to paint it or not...

[JgamB]

I just ordered some Eastwood Radiator Black - satin finish paint for science. I'll spray the top of my TMIC and leave the bottom naked.

This looks completely inconclusive without a radiator or engine/exhaust heat factored in, but for $15, who gives a shit. It's another fun and simple project to fiddle with.

[Natey]

Those guys just outsmarted Spearco, ETS, Garett, etc, or is there something we're (they're) not thinking about or measuring?

Seems like someone in the radiator business would have figured this out by now.

[Hargarbl]

Originally Posted by JgamB I just ordered some Eastwood Radiator Black - satin finish paint for science. I'll spray the top of my TMIC and leave the bottom naked. This looks completely inconclusive without a radiator or engine/exhaust heat factored in, but for $15, who gives a shit. It's another fun and simple project to fiddle with.

Before and after logs please, I'm really interested in this, I sit at about 130-140 bats when in traffic, definitely wouldn't mind seeing it drop a bit. Doing this a wrapping the cold side pipe with some reflective insulation might have some decent gains.

[Serphice]

this is pretty cool, but you would still have to tuck the FMIC away to make sure the sun is not on at all times or else the the additional cooling effect could backfire and actually be more harmful, on a TMIC? could work as the bonnet shields it from the sun.

still want to point out that the biggest addition is at idol and not at the simulated air flow, i may try this and make some logs

[SpencerC]

I never am sure what to think of Mighty Car Mods. I think they have fun videos, and some truth behind all they say, but they also skew how they say things in order to get the Youtube ratings. Just look at the Cold Air Intakes Mythbusted one. Many companies and individuals can prove that a CAI or SRI benefits the vehicle, but only on certain vehicles. That's why I would never do a SRI on my Miata, but it makes sense on the MS3.

Honestly the variable of the Hairdryer they used seems to be an poor choice in control. Nonetheless maybe it is true. It looks like painting it black can't hurt anything at the least. I would love to see some logs from someone who does this before and after.

[Voltwings]

Lets say you're using a TR8L since its a fairly common core here. If you paint the face of it, thats great, but the core is still 3.5" thick, you still have 2.9999999" of unpainted core for the air to pass through and do the cooling. The only way i can see painting the core causing issues is if you literally glob it on and it blocks the fins.

I refuse to watch mighty car mods, those guys are idiots and the people that watch them seriously (like the air intake episode) are even more stupid.

[BigO]

I definitely agree with you about their videos, Spencer. Especially the intake one. They did have one other great video where they tested some ebay piggyback chip that supposedly fudged with one of the sensor signals in order to increase power. After doing a before and after dynoed and seeing no change in power, they sent the chip to an electronic engineer that determined the circuit was literally a pass through that had LEDs on it.

As far as the hairdryer to simulate boost air it does seem like it could skew the results a bit. But as far as I can tell the logic behind the whole test seems pretty sound. This test was alot more scientific than all their other videos. Now is it as scientific as it could be? No, of course not. But it is by far the best test I've seen regarding black intercoolers.

Sent from my SM-G900V using Tapatalk

Also a disclaimer. I watch their videos for entertainment as that is their intended purpose. I do not use the videos a advice for working on cars.

Since some people obviously think everything MCM does is serious.

Sent from my SM-G900V using Tapatalk

[SparkySparks]

Originally Posted by Voltwings Lets say you're using a TR8L since its a fairly common core here. If you paint the face of it, thats great, but the core is still 3.5" thick, you still have 2.9999999" of unpainted core for the air to pass through and do the cooling. The only way i can see painting the core causing issues is if you literally glob it on and it blocks the fins. I refuse to watch mighty car mods, those guys are idiots and the people that watch them seriously (like the air intake episode) are even more stupid.

If you watched the video, you would see the awesome way they painted the core to make sure as much of it was painted as possible. One of them was spray painting while the other used a leaf blower to force the paint in as far as possible.

I wonder if you painted the underside of a TMIC white (to reflect heat from the motor) and the top/sides black (to shed heat) if that would be a better way of doing it?

I had the end tanks, sides and bottom edges of my ETS TMIC wrapped in reflective gold tape. No clue if it made a difference but I like the space ship look!

[Vansquish]

I just had a protracted discussion about the merits of this video with some people in my local facebook car-modding group. Here's why I would never paint my intercooler:

This won't really work for you if you've got a top-mount, as it'll absorb more heat from the engine than it normally would. Black is also extremely efficient as a radiation absorber. Moreover, in order for the emissive characteristics of a black intercooler to be additive with the convection/conduction characteristics that the device already has, the "paint" itself needs to be thermally conductive. In other words, it's probably better to have a black-anodized or powder-coated intercooler than it is to have it spray-painted.

It's also important to note that the coating is more likely to serve as an additional layer that decreases the surface area-to-volume ratio of the intercooler (this is bad for the efficiency of a radiator of any kind). If, on the other hand, the intercooler itself was made of Silver, Copper, Gold, or Aluminum (which most of our intercoolers are), then it is probably pretty efficient to start with, and our best bet is to try and a) improve flux through the fins, and b) reflect radiant heat away from the intercooler. Basically, it comes down to "no coating" is better than "any coating".

As far as heat soak is concerned. If you've got a front-mount, then the likelihood is that you're not going to suffer from this too TOO much. On the other hand, my ETS TMIC will heat-soak pretty quickly with the hood shut and the car stationary. If I'm moving at even a ~20-30mph rate, the intercooler will remain cool to the touch even on a hot day.

Finally, and perhaps most importantly, unless you're waiting in line at the strip, or at an AutoX course, then all of this is pretty much a moot point. The most important, and interesting, part of the MCM video is the fact that with air passing through the intercooler, the impact of the black paint was negligible relative to the effect of the air passing through the fins.

Originally Posted by SparkySparks If you watched the video, you would see the awesome way they painted the core to make sure as much of it was painted as possible. One of them was spray painting while the other used a leaf blower to force the paint in as far as possible. I wonder if you painted the underside of a TMIC white (to reflect heat from the motor) and the top/sides black (to shed heat) if that would be a better way of doing it? I had the end tanks, sides and bottom edges of my ETS TMIC wrapped in reflective gold tape. No clue if it made a difference but I like the space ship look!

Like you, my end tanks are Reflect-a-Gold wrapped as well. I did some relatively non-scientific testing (not enough trials for there to be any significance to the results), but it looked like my BATs dropped by a degree or two in traffic, at idle, etc.

[Dizzy Turbo]

I feel like this whole topic is just about people that wanna paint their intercooler justifying it so they don't get called ricers lol

Sent from my HTC One using Tapatalk

[BigO]

Originally Posted by Dizzy Turbo I feel like this whole topic is just about people that wanna paint their intercooler justifying it so they don't get called ricers lol Sent from my HTC One using Tapatalk

This, sir, is false. Because I openly admit I am a ricer.

Sent from my SM-G900V using Tapatalk

[DocBrown]

I'm calling bullshit on the idea of cooling via black body radiation and here's why:

1) Although black bodies emit radiation, they also absorb it. I don't care to work out the math on this but I would bet that they cancel out to a significant degree

2) Even if the black paint radiated more energy than it absorbed, the vast majority of the cooling surfaces of an intercooler are parallel to other cooling surfaces. In other words, any radiated energy would just radiate right back into adjacent fins.

3) As @Vansquish; stated, paint is more of an insulator than the metal the intercooler is made of and would increase the thermal resistance of the intercooler

4) I agree again with @Vansquish; that the paint is likely to fill in small crevices (lol crevices) between the fins and result in less overall heat sink area

5) Again some math is called for on this, but I'm confident that any black body radiation is FAR outweighed by the conductive cooling of the intercooler due to airflow.


I'm guessing that the paint was not fully dried when they did the second test (there was a primer layer and a paint layer), and a lot of the heat loss was due to moisture from the paint evaporating.

[SpencerC]

Originally Posted by DocBrown I'm guessing that the paint was not fully dried when they did the second test (there was a primer layer and a paint layer), and a lot of the heat loss was due to moisture from the paint evaporating.

I was thinking the same thing....

Time for one of us to do a "Unmighty Car Mods Black Intercooler MYTHBUSTED" and use a heat source better than a hair dryer, or do it on a real car, and let the paint dry.

AND

Do more than one test..... I don't know any scientist that would run a test once and claim that it's conclusive of every future test. Seriously run the same test 3 times at least to see if it proves true everytime.

[DocBrown]

Originally Posted by Spencer@CorkSport I was thinking the same thing.... Time for one of us to do a "Unmighty Car Mods Black Intercooler MYTHBUSTED" and use a heat source better than a hair dryer, or do it on a real car, and let the paint dry. AND Do more than one test..... I don't know any scientist that would run a test once and claim that it's conclusive of every future test. Seriously run the same test 3 times at least to see if it proves true everytime.

Hey if Corksport is up for donating a FMIC kit in the name of scientific research I'd be happy to carry out the experiment

Sent from my SPH-L710 using Tapatalk

[dale_gribble]

The theory behind the increased thermal efficacy is there but their setup is not good. The measurements were taken in a vacuum essentially (figuratively); not even the slightest attempt to create an increase in higher ambient air temperatures representing a realistic heat soaked environment. If our intercoolers didn't mount within inches of a radiator (FMIC) or motor (TMIC), maybe this test has merit but unfortunately they do. As the engineer mentioned, the paint increases radiation AND absorption of heat.

They should have put a radiant heater a few inches from the intercooler to simulate a nearby radiator with temps of 180-200F. My guess is that would have wiped out their gains going from non painted to painted.

Whenever I think of things like this, I always look to the OEMs and what they do. Take any group of engine/cooling system designers from any car manufacturer. They are infinitely smarter than these guys and intercoolers are still natural color/silver. Also consider the brightest of the aftermarket manufacturers. All of their intercoolers are natural color. Why?

If I had to guess, the radiant heat sources surrounding the intercooler completely negate the increased surface efficacy of the intercooler and possibly make it worse. It may even be beneficial to reduce thermal efficacy to reduce the effect of nearby radiating sources.

[Billcraft78]

Fuck it I'll give this a shot with my CPE tmic I'm seeing a lot of 130+ bats and around 115-120ish when moving. Stopped for gas and was at 160 today and didn't get any lower then 130 on the 5-6 miles back to the house. Also going to try the heat tape and coolant bypass. Would like to at least keep it close to ambient although that's prob not going to happen with a top mount. Fmic may be coming soon!!

[aviator79]

I had to repaint my spearco FMIC as it was shot so I wire brushed all the paint off the cast top and bottom and the "things" that the air goes thru between the exposed fins (sorry brain dead).

Time consuming but then went and covered all the fins before painting because I did not buy the special paint. After coating everything well I did a few light passed with the fins exposed.

Came out great but I would not have painted the whole thing without covering exposed air cooling fins.

I dont think it would make a huge difference but enough pain and will be less room for airflow and less cooling along with heat transfer issues between fins to paint to air.

And the whole black thing does not make any sense, but ive no reason to get into that. Paint it white and try the argument.

[mize13]

Snow is often considered an emissive black body (why you get burnt so bad when snowboarding), so lets not jump to conclusions about painting the intercooler based only on paint color. Need to know properties of the paint. Irraditiation (radiation incident on a real surface) is reflected, absorbed, and/or transmitted.

I would think a blackbody would be the worst option ( alpha = epsilon = 1). It basically absorbs all incident radiation and then DIFFUSELY emits is. Blackbodies are considered diffuse emitters, or they emit thermal radiation in all directions.

alpha + ro + tau = 1

Where:
alpha = fraction radiation absorbed
ro = fraction radiation reflected
tau = fraction radiation transmitted through surface

Need material that reflects incident radiation. This really only applies at idle where thermal radiation (i.e. valve cover to TMIC), natural convection, and conduction take precedence as primary modes of heat transfer. Once moving, forced convection dominates.

[Dizzy Turbo]

This is way to much science just to paint an intercooler. I mean even if it does help it can't be that much.

Sent from my HTC One using Tapatalk

[Lex]

I think this will be another myth on the internet and it's making quite a stir.

The end conclusion in the video is the most important and they don't emphasize it correctly. The amount of heat lost through radiation is negligible compared to the amount of heat lost via convection. So this will help when the car is stationary MUCH more so than when the car is moving. Overall it will have a very negligible effect. You can see that in the video the temperature delta was smaller when air was moving. This means that they actually lowered the efficiency of the convection process by applying the paint and the radiation effects from the color are not measurable even when a very smaller amount of air passes over the surface.

Also anodizing is the way to go for a durable finish. In a year of driving the intercooler will have a lot of rock chips with just paint.

[anodizedeeznutz]

Holding up great.


Sent from my iPhone using Tapatalk

[cyber-ms3]

Originally Posted by dale_gribble The theory behind the increased thermal efficacy is there but their setup is not good. The measurements were taken in a vacuum essentially (figuratively); not even the slightest attempt to create an increase in higher ambient air temperatures representing a realistic heat soaked environment. If our intercoolers didn't mount within inches of a radiator (FMIC) or motor (TMIC), maybe this test has merit but unfortunately they do. As the engineer mentioned, the paint increases radiation AND absorption of heat. They should have put a radiant heater a few inches from the intercooler to simulate a nearby radiator with temps of 180-200F. My guess is that would have wiped out their gains going from non painted to painted. Whenever I think of things like this, I always look to the OEMs and what they do. Take any group of engine/cooling system designers from any car manufacturer. They are infinitely smarter than these guys and intercoolers are still natural color/silver. Also consider the brightest of the aftermarket manufacturers. All of their intercoolers are natural color. Why? If I had to guess, the radiant heat sources surrounding the intercooler completely negate the increased surface efficacy of the intercooler and possibly make it worse. It may even be beneficial to reduce thermal efficacy to reduce the effect of nearby radiating sources.

It happens to be I do think that this test should be done more thoroughly, and I do agree with you and your statements but it does happen to be that SOME oem intercoolers are black. Look up supra mk III stock intercoolers, Grand National intercoolers, 3000gt, or even some porsches. Also many coolant radiators are black also and they are used in the same to dissipate heat. I'm not necessarily saying that black is the way to go but the argument of following what the oem and their engineers just might point in the other direction.

[Vansquish]

Originally Posted by cyber-ms3 It happens to be I do think that this test should be done more thoroughly, and I do agree with you and your statements but it does happen to be that SOME oem intercoolers are black. Look up supra mk III stock intercoolers, Grand National intercoolers, 3000gt, or even some porsches. Also many coolant radiators are black also and they are used in the same to dissipate heat. I'm not necessarily saying that black is the way to go but the argument of following what the oem and their engineers just might point in the other direction.

The fact that the GN, MKIII, 3000GT (and I'm not sure to what Porsche vehicle you refer) may have had black-painted intercoolers for a couple of reasons:

1. The intercoolers themselves are quite small in the MKIII Supra, and the 3000GT, so the effect of black-body radiation on those units may be more substantial relative to the conduction/convection characteristics of them as the surface area scales down.

2. It may also be that those intercoolers were located such that there was less airflow possible through them, or . . .

3. It may be that the intercoolers were located far enough from the engine/radiator that they were more shielded from thermal emissions from them, and therefore, there was less risk inherent in painting them black.

4. As for the GNX, the intercooler is still relatively small, so as above, it may have a higher thermal efficiency if painted black, or it could simply have been a cosmetic choice (that does happen occasionally, after all).

I still wouldn't paint a TMIC, and I don't think I'd want to add a layer of anything that might inhibit flow across the core, as the losses there are likely to be MUCH greater than the would be the gains from radiation-based heat loss.