Anodizing is the best way to go in FMIC
Feb 15, 2009, 05:18 PM
#1
Evolving Member
Thread Starter
Anodizing is the best way to go in FMIC
Hey all,
I'm about to have my car worked on at EnglishRacing, and one of the decisions I've had to make was regarding anodizing vs not anodizing my FMIC. After looking through this forum, I found a lot of posts both for and against it, but nothing that was backed up by hard analytic data (most of the backup was in the form of subjective and anecdotal stories).
I am making this post to help others trying to make the same decision. Following is a web based information exchange that I found through google:
http://www.audifans.com/pipermail/s-...ly/042433.html
Long story short, the answer is definitely to go for anodization.
To make some highly relevant points:
1. People have stated that anodizing (as well as painting) will impede thermal conductance of the FMIC. First of all, it should be pointed out that anodizing is NOT painting. It is an electrochemical process that leaves a layer of aluminum oxide that is much, much thinner than paint. Secondly according to the link above, the impediment to thermal conduction caused by anodization is more than offset by the improved emissive properties of the anodized surface (see below).
2. According to the data in the linked article, an FMIC anodized to a depth of 3um exhibited 92% of the emissive efficiency of a black-body object. Compare this with the emissive efficiency of polished aluminum: 4.6%!!
3. In case anyone needs some refresher, a blackbody object is an object that exhibits zero reflection, both for incoming and outgoing radiation. That is, if an infrared wave were to strike a blackbody object, it would be completely absorbed with no reflection. Similarly, an infrared wave that is internal to the object will be able to leave the object with zero percent of it reflected back inside. If this sounds weird, think of a diver inside an aquarium tank, holding a waterproof flashlight. If the diver shined his light on some of the kids gawking at him through the observation window, some of the light goes through the window, but some of it also gets bounced back into the aquarium. That is internal reflection. If the window behaved like a black-body interface, then none of the light would have bounced back. Going back to the data in #2, polished aluminum allows 4.6% of infrared heat waves to leave the FMIC and reflects 95.4% of the waves back inside! It's no wonder that space blankets have a shiny side, it really helps keep heat in!
4. The linked article does recognize that most of the thermal transfer achieved by an FMIC or radiator is through convection (ie, direct mechanical transfer of molecular energy). This is probably why so many people have hangups about adding an anodized coating to a radiator or intercooler. However, as the article points out, emissive radiation is also a mode of heat transfer, ableit a secondary one, but the emissive improvement from anodization are dramatic enough to overcome that convective penalty!
5. There is an illustrative example given in the article: an acquaintance had a shiny, unanodized aluminum heatsink attached to a computer chip. Under this arrangement, the computer chip often overheated and entered thermal shutdown. After replacing the heatsink with an anodized one of the same shape and size, the chip ran much cooler and completely stopped going through the thermal shutdowns.
I made my decision about 2 weeks ago, based on my vague memories from High School AP Physics about blackbody radiation, and Aaron at EnglishRacing has already placed the order for an ETS black anodized FMIC. This recent article find just vindicates my choice, and hopefully will help other people who are trying to make the same decision.
I'm about to have my car worked on at EnglishRacing, and one of the decisions I've had to make was regarding anodizing vs not anodizing my FMIC. After looking through this forum, I found a lot of posts both for and against it, but nothing that was backed up by hard analytic data (most of the backup was in the form of subjective and anecdotal stories).
I am making this post to help others trying to make the same decision. Following is a web based information exchange that I found through google:
http://www.audifans.com/pipermail/s-...ly/042433.html
Long story short, the answer is definitely to go for anodization.
To make some highly relevant points:
1. People have stated that anodizing (as well as painting) will impede thermal conductance of the FMIC. First of all, it should be pointed out that anodizing is NOT painting. It is an electrochemical process that leaves a layer of aluminum oxide that is much, much thinner than paint. Secondly according to the link above, the impediment to thermal conduction caused by anodization is more than offset by the improved emissive properties of the anodized surface (see below).
2. According to the data in the linked article, an FMIC anodized to a depth of 3um exhibited 92% of the emissive efficiency of a black-body object. Compare this with the emissive efficiency of polished aluminum: 4.6%!!
3. In case anyone needs some refresher, a blackbody object is an object that exhibits zero reflection, both for incoming and outgoing radiation. That is, if an infrared wave were to strike a blackbody object, it would be completely absorbed with no reflection. Similarly, an infrared wave that is internal to the object will be able to leave the object with zero percent of it reflected back inside. If this sounds weird, think of a diver inside an aquarium tank, holding a waterproof flashlight. If the diver shined his light on some of the kids gawking at him through the observation window, some of the light goes through the window, but some of it also gets bounced back into the aquarium. That is internal reflection. If the window behaved like a black-body interface, then none of the light would have bounced back. Going back to the data in #2, polished aluminum allows 4.6% of infrared heat waves to leave the FMIC and reflects 95.4% of the waves back inside! It's no wonder that space blankets have a shiny side, it really helps keep heat in!
4. The linked article does recognize that most of the thermal transfer achieved by an FMIC or radiator is through convection (ie, direct mechanical transfer of molecular energy). This is probably why so many people have hangups about adding an anodized coating to a radiator or intercooler. However, as the article points out, emissive radiation is also a mode of heat transfer, ableit a secondary one, but the emissive improvement from anodization are dramatic enough to overcome that convective penalty!
5. There is an illustrative example given in the article: an acquaintance had a shiny, unanodized aluminum heatsink attached to a computer chip. Under this arrangement, the computer chip often overheated and entered thermal shutdown. After replacing the heatsink with an anodized one of the same shape and size, the chip ran much cooler and completely stopped going through the thermal shutdowns.
I made my decision about 2 weeks ago, based on my vague memories from High School AP Physics about blackbody radiation, and Aaron at EnglishRacing has already placed the order for an ETS black anodized FMIC. This recent article find just vindicates my choice, and hopefully will help other people who are trying to make the same decision.
Feb 15, 2009, 08:00 PM
#4
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Bahhh, who cares anodizing or not anodizing. Go with what you want as far as looks go. I don't believe we are yet at the point we have to worry about the small amount of thermal transfer anodizing "MIGHT" make on an intercooler. If people are truly worried about heat transfer they should quit polishing the end tanks on their intercoolers since it reduces the total amount of surface area the tanks have to dissipate heat. In fact the should start welding on cooling fins. LOL, sorry but I couldn't resist. Lucas and Aaron rock as far as tuning goes and the Black intercooler looks great. Be sure to post some pics when you get everything installed =D
Feb 16, 2009, 01:45 AM
#5
Evolving Member
Thread Starter
Well, that's just the thing... according to the data in that link, anodizing, compared with a mirror polish, can add a significant amount of emissivity, and the anodizing seemed to make a huge difference for the computer heat sink. The quantitative effect may not be something to sneeze at. In these forums, when you can have heated debates over the merits of one LICP vs another, which is basically just a J-shaped piece of 3" tubing, I think it would be worth our time to address the anodizing issue.
Yes I have heard a lot of good things about Lucas and Aaron, and I really look forward to having them work on my car!
Yes I have heard a lot of good things about Lucas and Aaron, and I really look forward to having them work on my car!
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Feb 16, 2009, 12:11 PM
#11
^^^^ With the Garrett 3.8" intercooler core, it works great, too.
That is the same core that Buschur uses in the Race intercooler, but it costs $700 from ETS, so you can basically get the anodized version like is shown in the picture for nearly the same price as the "raw" finished one from Buschur...
That is the same core that Buschur uses in the Race intercooler, but it costs $700 from ETS, so you can basically get the anodized version like is shown in the picture for nearly the same price as the "raw" finished one from Buschur...
