Purpose of a blacked-out hood?

[asteffes]

I'm planning on doing this to the hood of my 80. The main motivation though is because I have some many rock chips on it that it needs to be painted anyway. Flat black is something easy that I can do.

Line-X!

 

[upcruiser]

Line-X!

I'm considering it actually, I did this to my fender flairs. We'll see. If not, I was thinking of masking it off, then using satin finish rustoleum and rolling it on with a roller. I did this on my old Troopers and it gave it a roughened finish that was easy to touch up if needed and cheap cheap cheap. I should probably suck it up and do the Line-X though.

 

[Colorado Ron]

LineX is hard to clean. Dirt gets in the little nooks and it always looks dirty. If thats your thing, it looks good. :smiley_drive:

 

[GeoRoss]

I think common sense and experience tells me that if the sunshine makes contact with any surface, black will heat up more than white. And all colors in between will be according to where they fall on the lightness to darkness spectrum. In the expiriment that Allen linked to, the black hood was 56 degrees hotter than the white hood, and that was on a Sept. day with 84 degree air temp. I think in July with temps in high 90's to over 100's would make an exponential difference. (add a hot running engine to the mix and the "exponential" factor probably goes waay up)

I agree completely that a dark color will absorb more heat/light/energy/etc. I think vagaries come to play in does the hotter roof/hood conduct heat to the interior/engine compartment and if so is it significant to warrant a different color option.

I got to thinking about these conflicting observations and I propose that a dark color hood will not effect engine bay temps while the engine is running. The reason I say this is that heat moves by conduction and follows the same principals of diffusion. It will always move to a place of lower heat, unless you are actively pumping the heat there .

In a running engine, the engine bay will most likely be hotter than its surroundings outside, forcing the heat to radiate away from the bay. If the vehicle is moving, all the better. If the engine bay is cooler than the surrounding evironment, it will become a heat sink and absorb it. Throw in the insulation and the inefficeincy of air as a conductive medium and the heat transfer will drop also. My educated guess is that while a black hood will be hotter to the touch than a white hood but it will not conduct that heat into the interior to an extent that warrants concern.

I will say that this is all a back of the envelop thought experiment based on general principals. I may be missing something. It is possible to do the math and calculate/model different scenarios of differing complexity. Either way it is fun to think about.

See you on the trails,

Ross

 

[BajaTaco]

I'm sure Scotty and Chris can attest to the glare that comes off the hoods of their rigs on a sunny day. Either one of them would probably be amazed at the difference a blacked out hood would make. Fatigue on the eyes has got to be lessened by this application.

For myself, and my particular truck, I don't find the white paint an issue. I think it will vary from person to person and vehicle to vehicle. Very little of the area of my vision is occupied by the hood in my particular case. probably a 2.5" (vertical) section at the bottom of my field of view out the windhield shows my hood. Seating position and height of the driver, along with length/slope of the hood will likely be the determining factors. In my wife's car, the hood isn't even visible from the driver's position (but it's a car with a short, sloped hood). Bottom line, I think if you find your eyes being offended by the glare from your hood, it's a good idea to do the black-out mod. Your eye performance & health is way more important than the difference in surface temps/engine temps. But on the flip-side, I still don't think it's worth adding (and or retaining) heat at the engine bay here in the southwest deserts of the USA if your eyes aren't suffering.

 

[BMAN]

For myself, and my particular truck, I don't find the white paint an issue. I think it will vary from person to person and vehicle to vehicle. Very little of the area of my vision is occupied by the hood in my particular case. probably a 2.5" (vertical) section at the bottom of my field of view out the windhield shows my hood. Seating position and height of the driver, along with length/slope of the hood will likely be the determining factors. In my wife's car, the hood isn't even visible from the driver's position (but it's a car with a short, sloped hood). Bottom line, I think if you find your eyes being offended by the glare from your hood, it's a good idea to do the black-out mod. Your eye performance & health is way more important than the difference in surface temps/engine temps. But on the flip-side, I still don't think it's worth adding (and or retaining) heat at the engine bay here in the southwest deserts of the USA if your eyes aren't suffering.

Chris,

Next time we have a planned trip together, I'd like to set you up with a temporarily blacked out hood for a day of wheeling to get your feel and thoughts on the subject.

I "know" for a fact that my eyes are overly sensative to light and I probably couldn't offer an unbiased opinion of the effects of a blacked out hood. Being that I also own a Tacoma, I will use my truck to find a way to rig up some kind of non-permanet/ non-marking black out to use for a day.

I think it'd be a fun little experiment to see if it really makes a noticeable difference to a person who is indifferent to the subject.

 

[BajaTaco]

Chris,

Next time we have a planned trip together, I'd like to set you up with a temporarily blacked out hood for a day of wheeling to get your feel and thoughts on the subject.

I "know" for a fact that my eyes are overly sensative to light and I probably couldn't offer an unbiased opinion of the effects of a blacked out hood. Being that I also own a Tacoma, I will use my truck to find a way to rig up some kind of non-permanet/ non-marking black out to use for a day.

I think it'd be a fun little experiment to see if it really makes a noticeable difference to a person who is indifferent to the subject.

I'm game!

 

[bigreen505]

They can also help reduce glare from roof mounted lights.

While I don't doubt the superiority of flat black, I have to wonder which is more important, flat or black. Would a matte white hood be a significant improvement over a shiny white hood. And while there is no answer for night driving, how much to polarized glasses even the score?

 

[ZooJunkie]

In the world of ricers and speed demons a blacked out hood usually denotes a carbon fiber hood or a popular tuner called Spoon. All of which does not apply to LR Discos.

Just more useless info.

 

[BMAN]

While I don't doubt the superiority of flat black, I have to wonder which is more important, flat or black. Would a matte white hood be a significant improvement over a shiny white hood. And while there is no answer for night driving, how much to polarized glasses even the score?

My WAG on this question would be that the hood be black first and matte second. Matte white will make little to no difference in the ammount of glare reduction as opposed to the reduction noticed by using a black hood. A matte texture will reduce glare on any surface, true, but the glare from the color itself IMO is just as great if not more.

Make sense?

 

[flyingwil]

They can also help reduce glare from roof mounted lights.

I thought that was the main purpose...

 

[Willman]

Anybody want to share any pictures of these hoods......Tacoma.....

160 degrees on the red rigs:Wow1: ....oh boy....I'm in trouble...gotta park in the shade....

:sunny: