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PostPosted: Thu May 14, 2009 3:18 pm 
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2 BBL ''SuperSix''

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I'm not sure this is a good idea or not ==>
http://www.forabodiesonly.com/mopar/sho ... hp?t=62613


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PostPosted: Thu May 14, 2009 3:22 pm 
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Supercharged

Joined: Thu May 12, 2005 11:50 pm
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Car Model: 64 Plymouth Valiant
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PostPosted: Thu May 14, 2009 5:10 pm 
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Is it a good idea? Yes, it's a good idea. Is it a good implementation? Probably not. All kinds of red flags go off for me when I read that thread and look at those pictures. Even if we apply the lower standards that were in effect in 1966, it's almost certain these LED boards do not produce the minimum required amounts of light for the tail and brake/turn functions, do not give the minimum required effective luminous lens area (dots of light with dark space among them) nor distribute the light through the minimum required vertical and horizontal angles. LED automotive lighting devices contain optics specifically focused to distribute the light from a cluster of LEDs appropriately; putting an array of LEDs behind a lens engineered to distribute the light collected by a reflector from a filament bulb does not result in a lighting device that performs safely or effectively.

What's more, it is definitely not true that "LEDs produce no heat". They produce a great deal of heat! It's just that the heat and the light are sent in opposite directions. Instead of the heat and light going out together as from a filament bulb, the heat accumulates at the rear (called the "junction") of the LEDs while the light goes out the front. This matters because LEDs' light output is highly dependent on junction temperature. The hotter the junction gets, the dimmer the light output. The colder the junction, the greater the output. Properly-engineered LED automotive lighting devices contain high-quality, high-output emitters, very effective heat sinking for the junctions, and sophisticated control circuitry to vary voltage to the emitters according to junction temperature. That way, the lighting device puts out about the same amount of light whether it's just been first lit up on a subzero winter morning, or you've been sitting there with your foot on the brake for ten solid minutes on a 110° summer afternoon. This kind of engineering and component selection is costly, which is why "Hey, lookit how much less these boards cost than other boards I've seen!" is a good reason to avoid them, not to buy them.

And we've already been thru the reasons "LED bulbs" are a poor idea.

More info here and here. I'm not sure I'll chime in on the FABO thread; sometimes True Believers don't want their delight to be spoiled with facts. Maybe someone else will post a link on FABO to this thread here. The guy's absolutely right that the '66 Valiant & Barracuda taillamps are poorly designed. The sun broils them from above, and the bulb bakes them from below. Not much can be done about the sun, but a better way to solve the bulb-melt problem is to put a custom-cut piece of heat-absorbing glass between the bulb and the lens.

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PostPosted: Thu May 14, 2009 6:30 pm 
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Supercharged
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Joined: Sun Nov 03, 2002 9:20 pm
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Location: Fircrest, WA
Car Model: 76 D100
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The guy's absolutely right that the '66 Valiant & Barracuda taillamps are poorly designed. The sun broils them from above, and the bulb bakes them from below. Not much can be done about the sun, but a better way to solve the bulb-melt problem is to put a custom-cut piece of heat-absorbing glass between the bulb and the lens.
Not true! Someone could build some louvers for the taillamps to shield them from the sun! Of course, then tall vehicles like semi trucks also couldn't see the taillights...


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