Racer X

What is the current recommendation?
Looking for Product, Vendor, Color choices

And:
Is it true that the hot side should be black to minimize radiant heat and the compressor side should be silver or white to radiate heat and prevent absorption which would increase intake temp?


Thank you in advance.

concealer404

iTrader: (3)

Compressor should be dick tip purple.

WigglingWaffles

+1 for dick-tip purple

Color has no bearing on heat transfer, type of coating does. Ceramic coating or a turbo blanket, pick your poison.

Spaceman Spiff

Welllllll they don't call it black body radiation for nothing....

​​​​​Perhaps a slightly lighter hue of dick tip purple?

technicalninja

Coating COLOR has almost no bearing on heat transfer UNLESS it is exposed to sunlight.

The difference in internal temperature between a black and a white Suburban IS massive (50+ degrees more for the black one) until you put both vehicles INSIDE a parking garage out of the sun.
Then it doesn't matter at all...

I once had a black Suburban that would pop evaporator cores for no apparent reason while parked.
Turned out the owner was trying to save money and had stopped parking in a garage to save $60 a month.
She saved no money at all.
I had the dash out three times...

In my book the blankets ARE poison. Yes, keeping heat in the turbine is helpful until it is SO MUCH heat that it cooks stuff.
I see more problems with blankets than benefits.
Ceramic coating is "THE WAY" IMO...

Spaceman Spiff

There are a couple of 200 year old austrian fellows who would disagree with you. Turbines get up to what, 6-700c? I would guess radiative heat transfer is non-insignificant

In it's most generalized form (e.g. most number of assumptions and simplifications), power of heat transfer due to radiation is



where that little e term, emissivity, will range from 1 for a perfect black body (i.e. the color black) to 0 for something perfectly reflective. So yes, a black ceramic coating will "keep less heat in" compared to a white or light grey one.

No clue if that actually matters though ¯\_(ツ)_/¯.

DNMakinson

iTrader: (3)

The color at frequencies that the human eye can register are not the frequencies that emit infrared (heat) radiation.

Ceramic coatings function primarily in reducing conducted heat (holding heat in the metal, below the ceramic coating) which is the main subject of this discussion.
DNM

technicalninja

Thanks DNM for another tasty tidbit...
I wasn't aware that the color you can see is NOT part of this problem.
I was aware of Spaceman Spiff's bit on radiant heat. He is 100% correct too, hence my comment "almost no bearing".
I doubt that those Austrian fellows were putting little "sources" of heat in an engine compartment.

If you will look up at the original post Racer X has it backwards...

The color of the coating is a MPITO difference.
MPITO = mouse **** in the ocean. IF a mouse pisses in the ocean does it change the volume? Does it matter?
Going with "dick tip purple" is fine. Ordering that "color" from your ceramic coater might be a challenge.

For me ceramic coating is "the way" but I'm not going to pay much for them. They can help but once again it is MPITO in my book.
Keeping the excess heat that a turbo WILL radiate out of the engine compartment is a far bigger "helper" IMO.

I'll stay with what ever finish came on the original turbo.
Having NO finish means you will not be pissed 5 years from install when the ceramic stuff starts to flake off. I've never encountered a really permanent coating yet.
White ceramic coating seems to attract dirt and grease. Once it's been stained it never looks right.

I'll make a turbo "shield" out of stainless and vent it. Both a dedicated inlet and outlet. I'm doing just the opposite of what this thread is about. I'm disposing of the heat the turbo is shedding.
This shield can be very thin...
The outer "skin" of a stainless kitchen appliances is excellent material for this. Find a stainless refrigerator on the curb, broken, and you're set for stainless sheet for awhile.
Be careful here. The skin is razor blade thick and can cut you badly. It can be SO sharp that it doesn't hurt. Your first indication that you are cut is all the red stuff that magically appears.
I know this from personal experience...
I'll try to not mount it on hot things but often you have no choice, you have to mount it directly to the turbo or exhaust manifold.
It needs an airspace between the hot thing and shield and on the other side between the shield the things you're trying to keep cool.
It's the air spaces that are the insulating factor. Blowing fresh ambient air into the hot side helps immensely.
Stainless is also a lousy conductor of heat.
A good shield can reduce the amount of heat that is TRANSFERRED into the engine compartment by a significant measurable amount.
On a Datsun Z car it can be the difference between melted shoes and an ambient foot well. I'm sure the Miata is no different.
I will commonly continue this shield past the transmission ONLY between the exhaust down tube and the car. I don't fully shield the pipe, only 1/2 of it.

I'll save the ceramic coatings for areas that I think it gives the greatest advantage on; piston crowns, combustion chambers, and exhaust ports in the head.
These points keep the heat out of the cooling system and apply the heat to the turbocharger.
These are the points that I think the coatings are worth more than MPITO...

And now certain people who read this will be FAR more likely to trash hunt for materials...

TL/DR: Color of coating doesn't matter, keeping heat out of engine compartment does, pick up ALL discarded stainless kitchen appliances for materials.