Header Wrap: White or black?

[OctaneMotorsports]

Quick question for you engine builders and other knowledgeable people;

I am re-doing the headers on my Formula Veerace car (sandblasting, re-painting, full header wrap). The engine is a modified VW Beetle H-4 air-cooled engine from the 60's with racing exhaust, which is basically a set of headers with a straight pipe out the back. The key with these engines is reducing temperatures in the engine compartment. The lower the temperature, the most horsepower you have. The key is to try and reduce or eliminate the engine losing power as the race goes on and the engine compartment gets hotter.

I'm going to the race shop today to buy new header wrap for it, my question is which color will (in theory) result in lower engine compartment temps, white or black? I plan on wrapping the entire exhaust system and some other hot areas as insulation. I figure black would retain heat better but I figure I would get an expert opinion before I do this, thanks.

 

[kbs2244]

Since the wrap is basicly insulation to keep the heat in the pipes, I don't think the outside color means much. It is the warm side of insulation that is inportant.
The air cooled engine guys used to get in big arguments over weather black fins readated heat better than uncoated. One side said black was a better radiating color. The other side said you were putting a insulating coat between the fin and the air.
Now days, most of the "go before show" engines I see have uncoated fins.
If you have overheating problems you may want to look into some airplane cooling system design books. The good ones have inlet size, outlet size, air route baffling and baffling sealing down to a sicience. And sometimes what seems wrong is what works best. Contact the EAA (Experrmital Aircraft Assoc) in Osh Kosh, WI they have a good book store.

 

[OctaneMotorsports]

My race kart engines used black cylinder heads not for lower temps, but for "better, more equal heat distribution".

 

[bobss396]

Most of the wrap material kits I've seen have been a tan color. It gets crapped up soon enough and will get darker. There are color coatings that can be sprayed on top of them.

 

[Yotaforce]

I'd go with the black. Considering the color of the wrap probably won't change temp. enough to be noticable, but atleast the color won't be affected much when working on and around the engine and grease, oil, and dirt won't hurt the appearance. If you want to keep the heat out, give it a more directed place to go using forced air ducting to push the header heat down and out of the compartment. Like a brake cooling duct. Being that it is allready an air cooled, you would just be adding additional ducts to force new cooler air into the compartment and thus forcing out the heat.

 

[Slim-Pickins']

Darker colors RETAIN heat ... lighter colors DISSIPATE heat, relatively speaking.

Next sunny day, go lay your hand on a black car ... then go lay your hand on a white car ... same radiated heat absorbed from the sun, yet the white car will be cooler as it dissipates the ambient radiant heat faster.

 

[rsanter]

I hate header wrap (but will admit it has its place in the world)
I would recomed you have the headers ceramic caoted inside and outside. the stuff works great and looks good. I liked it so much that I ended up doing the entire system all the way out the back (other than the mufflers).
you can still use the wrap over it if you feel the need.
I would use white for function only. if its looks you are concerned with then use the black as it dosent get shabby looking so quickly.

bob

 

[Vernmotor]

Header wrap = rusted out headers..been there. done that..Try real hard not to use it,,build heat shields if needed..

 

[wrenchr]

Powder coat inside a out work's well for heat disapation.

 

[HOTFR8]

I find the Jet Hot Coating better than any wrap.

 

[comp]

i have had real good luck with the brush on silver stove paint,,inside and out heat cycle it several times do any touch up you need then wrap

 

[Yotaforce]

Darker colors RETAIN heat ... lighter colors DISSIPATE heat, relatively speaking.

Next sunny day, go lay your hand on a black car ... then go lay your hand on a white car ... same radiated heat absorbed from the sun, yet the white car will be cooler as it dissipates the ambient radiant heat faster.

Take a propane torch out to your black car and heat up a spot. Then try it on a white car. Touch both with your hand and compare the burns to your skin. You are talking about heat absorbtion by means of LIGHT. The heat he is referring to is from a fire breathing engine. Give me a break. The white REFLECTS heat from the sun while the pigment in the black absorbs it. Let me know how well it works with the torch.

 

[Yotaforce]

Bump! How about that torch idea? Any results yet?

 

[Wastedwagesracing]

I think he is still at the E.R.

 

[comp]

I think he is still at the E.R.

 

[BrianAltenhofel]

My race kart engines used black cylinder heads not for lower temps, but for "better, more equal heat distribution".

Sounds like a marketing scheme to sell more black cylinder heads.

I'm interested, too, about the torch test. I haven't seen anything about a lawsuit here yet.

Remember, if you get burned using the torch test, go to California and file a lawsuit that the torch manufacturer did not include a warning label about heating up a metal object and touching it immediately afterwards. Then buy two 3,000 acre ranches: one in Texas and one in Montana to cover all seasons. Proceed to early retirement and invest most of your settlement and live off the returns for the rest of your life.

 

[Yotaforce]

I guess it is settled. Wether you put a torch to a white car OR black, they must still build up to the same temps. Either that or someone is out burning the paint off their car holding an infrared temperature gun in the other hand trying to make sense of it.

 

[rsanter]

I know people that paint only the ends of their aluminum heads to try to even the heat in the heads

go the easy route. cruze through a local parking lot untill you find a white car parked next to a black car. put one hand on each untill you can no longer stand it or untill the owner comes out and beats the &^#$ out of you

bob

 

[sam 8]

Octane some feedback from a newbie here if you haven't already jumped.
My experience with the wrap is that it goes away quickly and takes the pipe with it.
If the headers are a long term investment, and not subject to getting pounded on the track, get them JetHoat cated as previously suggested. The coating is awesome. My 1776 in a street bug has a Kymco merged 1-1/2 inch setup on it and I am quite pleased with it.
When we built a set of headers for my last V-8 sand rail, we sent them off and had them coated. Painless process, and the 600 + ponies the little Chevy was making didn't so much as put a blush on the primaries.
Additionally, if you are running a turbo the coating is a + as well.

 

[Yotaforce]

That's true. The wrap does tend to retain moisture when the engine cools down (also depending on humidity) and it will definately promote the rust and rot away the header.