Shiny vs matt black - heat soak in the engine bay?

[petew]

Bout to finish up a bunch of things in the engine bay. I'd really like to paint it all matt black, but I don't want extra heat soak. What's everyone's thoughts/experience?

Should I paint the inlet tubing/intercooler black or have it shiny?

P.s. the intercooler is a water to air type.

[madmike]

Keep it shiny Pete,paint will hold in heat

[sideshow]

Have you ever tried to clean semi-flat? Choose the easy to clean whatever.

[Chip Birks]

Mine has been shiny metalic black, currently silver, and may get a color change this winter, just for fun. In the long run turbo sizing and intercooler efficiency will have way more effect on temps than paint color. Make it look cool, and call it done

[jhoefer]

Polished/chromed metal will both absorb less heat and radiate less heat. Matte black painted metal will both absorb more heat and radiate more heat. Depends on the relative temperature of things and what you are trying to do.

If the air inside a particular inlet pipe section is hotter than the surrounding engine bay air, you'd probably see some small benefit from painting it matte black. If colder, you'd probably see some small benefit from polishing it. In my opinion, not really enough difference to outweigh the aesthetic choice.

[aircooledtechguy]

The ONLY time you will ever experience any heat soak is after you shut down the motor and then what does it matter?? This goes for engine tins too. I've been hearing this debate for years on these forums and the logic is foolish. We're not dealing with radiant heat with no air flow like in an oven. You have a literal hurricane/typhoon/cyclone (pick your favorite noun ) of air flowing through your piping (and engine tins) when the motor is running. It's only going to be about as hot as the air flowing through it while the engine is running.

Make it look good and don't worry about color, shiny or matte; cause it makes not a bit of difference.

[Ol'fogasaurus]

The ONLY time you will ever experience any heat soak is after you shut down the motor and then what does it matter?? This goes for engine tins too. I've been hearing this debate for years on these forums and the logic is foolish. We're not dealing with radiant heat with no air flow like in an oven. You have a literal hurricane/typhoon/cyclone (pick your favorite noun ) of air flowing through your piping (and engine tins) when the motor is running. It's only going to be about as hot as the air flowing through it while the engine is running.

Make it look good and don't worry about color, shiny or matte; cause it makes not a bit of difference.

Several car manufactures did make after shutoff fans that stayed on to cool things off/circulate the air under the hood. If there is a worry ....

[aircooledtechguy]

The ONLY time you will ever experience any heat soak is after you shut down the motor and then what does it matter?? This goes for engine tins too. I've been hearing this debate for years on these forums and the logic is foolish. We're not dealing with radiant heat with no air flow like in an oven. You have a literal hurricane/typhoon/cyclone (pick your favorite noun ) of air flowing through your piping (and engine tins) when the motor is running. It's only going to be about as hot as the air flowing through it while the engine is running.

Make it look good and don't worry about color, shiny or matte; cause it makes not a bit of difference.

Several car manufactures did make after shutoff fans that stayed on to cool things off/circulate the air under the hood. If there is a worry ....

You are right and those cars maybe do not suffer from quite as much post shut-down heat soak onto the hood & paint as cars that don't. But all those cars are water-cooled and it's the radiator fan that is primarily getting the air. We're talking air-cooled engines where the fan only runs when the motor is running. There's no way around heat soak upon shut-down no matter what the tin is coated with. But what I am talking about is fretting over shiny/matte, painted white/black, Chrome/painted, etc. None of that makes a single bit of difference while running the motor or the temp of said motor. Where chrome tins get the bad rap (but somewhat deserved bad rap) is not in the chrome coating, but rather in the poor fit that is ALWAYS associated with that cheap chrome crap. They also don't usually have the deflectors in the cylinder tins to guide the air like OEM German tins do. Combine poor fit and poor manufacturing and you have a hotter running motor, irregardless of the coating. But somehow the coating gets the blame since that is always associated with that tin. . .

Coating color while the engine is running is the stuff of myths that's perpetuated by internet parrots.

[Marc]

Coating color while the engine is running is the stuff of myths that's perpetuated by internet parrots.

I agree. Coating color has no appreciable effect until the metal is hot enough to glow - hopefully never a factor on an engine

[Ol'fogasaurus]

I think my comment was miss-understood.

If you feel that under hood temp are a problem add a heat switched fan for venting residual heat after shut down.

The days of color engine compartments are an off and on thing. Flat black is very common but gloss colors like gloss black show the bling off better.

Again, if you think there is a heat build up problem then put a vent fan in place to move the air around.

With the new fad in covering the top of the engines with a formed cover then painted it looks to me like you have less room to get rid of heat naturally. They really make the engines look larger. I think pancake engines could have the same look if one wanted to be creative and try it.

I forgot to mention that flat colors are usually easier to touch-up!

[Piledriver]

I saw a V twin the other day at work that was black and burgundy---
Tank, fenders were sprayed out in black truck bed liner, frame/some of the tin and seat trim burgundy, pipes/engine etc flat black coated.

It actually worked awesome, visually.
Not anything to do with cooling, but color, texture and contrast matters for looks.

Truck bed liner on engine tin/fan housing/firewall/inside deck lid ... engine cover for busses/squares might tend to shut down the rattles//noise, considering trying it.