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The Mighty Car Mods test: • Black Intercoolers Myt...
So, I’m watching that old episode of MightyCarMods, for kicks … because I really like their channel.
And then imagine my surprise as I find myself pleasantly shouting my vehement disagreement into the face of my computer at the conclusion to their report. It’s called ‘Black Intercoolers Mythbusted’. (Link in the description.) It’s had 1.3 million views over the past three-and-a-half years. And it is just wrong. Right at the end.
Together with a mechatronics engineer named Mouseworks, Marty and Moog ran a brilliant experiment … and then they botched the conclusion, badly.
Mighty Car Mods decided that painting your intercooler black makes a massive difference to its thermal performance - and therefore makes your hot car even hotter. By making the inlet air cooler. And at that point, my engineering spider sense wrote an outraged letter to my management team, requesting an urgent jihad on bullshit, and here we are.
I love me a good jihad on bullshit, but I don’t want to disrespect Marty and Moog, and in any case, they got nearly all of it right … except the conclusion. But it does worry me that thousands of fine, upstanding car modifiers have subsequently wasted a perfectly serviceable Saturday afternoon (or something) painting their intercoolers black - and ultimately making their turbocharged car go slightly worse...
...which I’m sure was not the intent. So, the better for you to understand the tao of heat transfer, let us go live now, to Shitsville.
The Mighty Car Mods chaps ran a great experiment. They plumbed a hairdryer into the inlet of the intercooler and cranked it up. When the temperatures stabilised they measured the difference in temperature between the air going in and the air coming out (on the engine inlet side).
They came away with four critical measurements - two with the intercooler unpainted (as bare aluminium - or ‘aluminum’ if you’re American). And then two with it painted with one coat of etch primer and one coat of matte black over the top (to boost its emissivity).
They did two different ‘black versus bare’ tests - one with no airflow through the intercooler and the other with airflow from an electric radiator fan plugged into a car battery.
They found that when there was no airflow through the intercooler - like when you’re idling at the lights - the silver intercooler in their experiment had a temperature differential of 38 degrees C between the inlet and the outlet. When it was black (with no airflow) the temperature differential climbed to 77 degrees.
With the fan on, the silver intercooler rocked in with a temperature differential of 100 degrees, and the painted one posted 97. And it must be said there was a great deal of urinating in the trousers over the ‘no flow’ result (38 degrees climbing to 77), while the 97 versus 100 degree result for the ‘fan on’ tests was dismissed as insignificant.
This was the point, I think, where every engineer or scientist who ever watched that video had to projectile vomit into a bucket. I know I did. Because that 97-versus-100 result was basically ‘game over’ for the case for painting your intercooler black. Meanwhile, in Shitsville:
I know I spend a lot of my life kicking carmakers in the wedding vegetables for making fundamental mistakes, but the fact is, modern intercoolers and radiators are left unpainted for a reason - because it maximises their convective heat transfer performance. Or, if you neglected to study, you get maximum inlet air voodoo, nude.
If carmakers could make modern radiators and intercoolers more efficient by painting them black, they would.
You don’t work as an engineer in R&D without being a proper brainiac. These are places that practice computational flow dynamics like an extreme sport, modelling the flow pathways of differential elements of air inside the engine bay.
They are all engineering Yodas. So it’s inconceivable that just such a brainiac watched the Mighty Car Mods video and saw a lightbulb illuminate mid-air, and thought - ‘Why didn’t we think of that?’ Black. Yes!
If black paint worked, you’d save tonnes of aluminium. Plus, the intercooler could be made physically smaller, which would help with the packaging in the engine bay. If black helped, they’d be black, ex-factory. Unfortunately, it doesn’t. Which is why they’re not.
So the differential diagnosis for ‘should you paint your intercooler black?’ is: It’s not black ex-factory, and making it black would be an easy, cheap win for the manufacturer, if it worked. Therefore, it doesn’t.
Негізгі бет Автокөліктер мен көлік құралдары The truth about painting your intercooler black | Auto Expert John Cadogan
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