SVOBoy and I were chatting about this tonight.

The idea is that by painting your intake manifold black you will increase the temperature of the air being sent into the engine. This is based on (I assume) the fact that black attracts heat.

I personally don't think there is any validity to this type of thing for a number of reasons.

Instead of being a negative off the bat I figure I'd open the floor to others.

Yes/no? Pros/cons?

I would think that there wouldn't be much benefit. It seems like this would only work for capturing heat from the sun. If anything, in an engine bay that's basically isolated from the sunlight, if painted, the paint may possibly provide a layer of insulation from the engine heat. Thoughts? Comments?

__________________
Horsepower is how hard you hit the wall, torque is how much of the wall you take with you.

2007 Prius,
http://www.gassavers.org/gaslog/sig.php?id=2 http://www.gassavers.org/gaslog/sig.php?id=13 http://www.gassavers.org/gaslog/sig.php?id=124
http://www.cleanmpg.com/garage/images/his423.png
http://www.gassavers.org/gaslog/sig.php?id=447
Team Slow Burn

In heat transfer, we learned about 'black body radiation.' The only way something painted black will absorb more heat is through radiation [not convection or conduction]. In all actuality, a 'black body' doesn't even have to be black...it doesn't even really exist. It is a theoretical body that has an absorptivity value of 1 [conversely, an emissivity value of zero]. Unless you have something under your hood that is emitting radiation energy, or unless you drive around in the daytime with no hood, I personally don't think you will see any benefits.

Sorry to jump to the negative side.

Me: Say something about why black will make the IM hotter.

DrDisco: because it absorbs radiated heat, while shiny **** will reflect it

Me: And what about black and light, does it still make sense?

DrDisco: light?

Me: Light being absorbed by black, but no light under the hood...

DrDisco: light is one kind of radiation

DrDisco: heat is another

DrDisco: heat does not require light to radiate

Me: Thank you, sir.

DrDisco: energy is interesting

Me: Guy I'm trying to convince won't buy it.

DrDisco: that what, heat is radiation?

Me: That it'll get hotter without light.

DrDisco: how does a microwave work

DrDisco: hint: the little light doesn't heat the food...

DrDisco: like an oven

DrDisco: radiant heat

DrDisco: not light

DrDisco: the microwave uses high-frequency radiation

DrDisco: light is a narrow part of the electro-magnetic spectrum

DrDisco: you've seen Predator?

Me: No.

DrDisco: oh

DrDisco: that's sad

DrDisco: anyway, you've seen infrared pictures, right?

DrDisco: pictures of heat, instead of light

Me: Yes yes.

DrDisco: and they can be taken in complete darkness, like the military stuff

DrDisco: so heat does not require light

Me: Why would a black IM increase the heat?
tallguy pw0: well does a black car get hotter then a white car
tallguy pw0: in the heat
Me: But there is no light under the hood.
tallguy pw0: do a test paint a spoon black and paint one white, put them in the oven and see wich one gets hotter. if you have a infrared thermometer
Me: Hmm.
tallguy pw0: search ht there was a thread about it

I still need to search h-t about it.

Quick question... Is the engine itself emitting radiant heat?

Ah, this takes me back to the good old days of carburetors. Back then, most cars had a tube that snaked its way from a shroud around the exhaust manifold to the carburetor. This was because when air accelerates through a venturi, it gets cold. The cold air would then condense water from the air and ice up the carb throat. The automakers added the warm air tube to prevent icing.

I had several unpleasant experiences with carburetor icing. When I was driving my ex-wife to the hospital, the carb in my Ford Maverick iced up, and I had to pull over. A State Trooper stopped and took her to the hospital. After the car sat a while, the ice melted, I was able to restart, and I finally made it the last few miles to the hospital to see my son born.

I also drove from Burlinton, VT across Canada to Sault Sainte Marie, MI on a cold, clear winter night in a Fiat whose carb heater tube was missing. The Fiat had a 2 barrel carb, and when the primary iced up, I just tromped on the gas to open the second barrel. This kept me going, but carb secondaries always run rich, and the gas mileage sucked. I was running out of gas, so I stopped at a closed gas station. I left the engine idling for heat. When it finally ran out of gas, I nearly froze my hiney off. In the morning I was able to get some gas. Damned carb iced up just about the whole trip, but after nearly freezing to death, I was a lot more careful about keeping the tank full.

So, if you really want to warm the intake air, install a shroud over the exhaust pipe and run a tube to the air cleaner. That'll be a lot more effective than black paint.

__________________
Capitalism: The cream rises. Socialism: The scum rises.

Yes it is. Someone should probably try this. I still think it isn't going to get that much hotter though.

The thing that got us started on this was the guy that painted his intake (whole thing though, not just the manifold) white and claimed a 10C reduction in IATs.

Even there is no visible light in a "thermos" the innerside of it is silvered in order to reduce infrared radiation to go out ..So opposite must be somewhat true also: Black paint probably absorb more infrared radiation generated from engine even no single visible light ray exists under the hood.
But i also think that it will not make much difference.

I don't think it will make a difference. If it will the change would be very small.

__________________
2008 EPA adjusted:
http://www.gassavers.org/gaslog/sig.php?id=249
http://www.gassavers.org/gaslog/sig.php?id=414
Distance traveled by bicycle in 2007= 1,830ish miles
Average commute speed=25mph (yes, that's in a car)

So, would painting the EXHAUST manifold black, make it retain heat more? That's where I'm drawing my intake air from, so a hotter exhaust manifold would yield hotter intake air?

Now painting the intake manifold black is interesting -- I've seen a lot of black high-density plastic intake runners on late-model Ford V-6's (I think they stay cool to the touch because the plastic dissipates heat). So, I think the laws of heat transfer would apply more. Touching anything metal under the hood would be hot because the hot engine parts touch other metallic parts, and the heat is transferred from metal to metal (even the intake is really hot sometimes). The radiant heat around the engine probably wouldn't add much, but tapping into a coolant line and running the line around the intake or throttle body would be a better bet -- it could possibly radiate the heat to the metal parts -- just brainstorming. How easy this would be -- not sure, just make a Y-line from the engine's return line and wrap it around and back, or even a small radiator near the intake, and back to the circulation.

RH77

__________________
http://www.gassavers.org/gaslog/sig.php?id=7

well, according to my ASE book, painting something black make's it give/recieve radiant heat easier. especially flat black.

also, we must remember that radiant heat is light, even if we can't see it.

dark colors absorb radiant heat, but also give off radiant heat quite well.

a black exhaust manifold will increase underhood temps. a white one would act somewhat like a heat-shield. a black intake manifold will be more succeptable to radiant heat, but generally it's on the other side of the engine.

how much of a difference will it make? not much. honestly, i haven't been keeping with this discussion, but i think you'd be wanting for colder air, as on a carb'd car, that would lean out the mixture.

oh, rh77, if i remember right (i didn't look this one up) plastic doesn't dissapate heat well. it's actually a good insulator. that's why pot handles and stuff are plastic.

oh, on another note, one of the best ways to measure efficiency of a motor is by measuring the difference between the intake and exhaust temps, the bigger the difference, well, you get the idea. i might be talking out of my ***, i'll go look it up.

After posting that, I got to thinking about it -- thanks for the catch. It resists heat via insulation; I'm not certain if it easily gets rid of heat that it does end up absorbing. Also, heat transfer would be less due to density, I'm guessing. I have high-temp flat-black that I painted on my chipping mufflers (on the TL). I might spray some on the exhaust manifold + heat shield in the Integra to see what happens. I have loads of data on intake air temps to compare/contrast.

RH77

__________________
http://www.gassavers.org/gaslog/sig.php?id=7

i talked to my autoshop teacher if that would work. he's tried it all over 30+ years in the garage. it dosent do jack ****. just like matt said.

__________________
I ♥ my EM2
http://www.gassavers.org/gaslog/sig.php?id=189

Need this stuff gone!
http://www.honda-tech.com/zero...67053[/B]