headlight upgrade
Headlight bulbs are pressurized to about 10 atmospheres, cold. They are designed to handle the heat and pressure resulting from running one filament at a time. They are not designed to handle the heat and pressure, nor the current on the common
filament support lead. of running both filaments at the same time for more than very brief periods during beam changeover or headlight flashing. Doing so carries the very real risk of the bulb grenading inside the headlamp, destroying it. Some people who think they're clever wire it up this way anyhow, and the "Brite Box" people have made a business out of this "clever" (not) modification. Running the lows together with the highs can only be done safely if the lows are
produced by different bulbs than the highs -- it's a common modification on systems that use a single-filament low beam bulb and a single-filament high beam bulb on each side of the vehicle, and which come wired from the factory to turn off the low beams when the high beams are switched on.
The reason why some systems come that way is to do with provisions in the US headlamp beam regulations regarding foreground light -- that is, light striking the road surface relatively close to the vehicle. If the combination of high + low produces more than a certain amount of light at a certain downward angle, then the lows have to be switched off in high beam mode (with certain exceptions, see below). Too much foreground light works against the night driver's distance visual acuity, because the brightly-lit foreground causes the pupils to constrict, reducing the amount of light entering the eye. At the same time, increased foreground light causes the subjective impression of "good" (or "better") lighting.
This is probably the prime example of how the human visual system is a lousy judge of its own performance; it's very easy to create situations in which we think/feel our ability to see is much better or much poorer than it actually is. On the other hand, factory Xenon (HID) systems, which in most cases give very high levels of foreground light, are required to leave the low beams on with the highs. That's because it takes awhile for a Xenon lamp to come up to intensity after it's switched on. If you turn off the Xenons to go to high beam, then you need to switch back to low beam, you've got a dangerous "black hole" until the Xenons come up. There are lots of complaints from owners of cars with single-Xenon headlamps (Xenon low, halogen high) that their high beams are uselessly weak. There's some basis for that complaint, but the bulk of it is because the high beams, no matter their actual performance, are rendered useless for long-distance seeing by the brightly-lit foreground on account of the high-intensity low beams. There's no right answer here, just different compromises on a philosophical continuüm. The better your low beams are, the better your high beams have to be or else the gap in their objective performance will be aggravated.
As for which headlamps to put in your single-headlamp car: Reputable-brand ones, whether you have Money to spend or you don't. If you don't have Money, get GE Night Hawk H6024NH sealed beams, about $20 apiece from amazon.com (put "H6024NH" in the search field). Not the world's best headlamps, and they're still throwaway sealed beams, but they're the world's only decent cheap 7" round headlamp. All other sealed beams are junk (because made on decrepit tooling), as are cheap replaceable-bulb units. Forget the Chinese garbage from APC, Eaglite, Maxtel, Sirius, Pilot, Adjure, and eleventy dozen other brands, and the Indian-made garbage from Autopal and Neolite. They are dangerous headlight-shaped toys that do not produce adequate performance for even creeping along at 25mph, let alone normal road speeds.
If you have Money to spend, pick your equipment carefully even though the field narrows down to about three reputable brands that are practically easy to get (there's a really nice Koito 7" round H4 headlamp, but it's costly and difficult to get). Hella and Bosch are widely available and well made of good quality materials, but their optical efficiency lags pretty severely -- this post is growing long as it is, but if you want detailed discussion and proof on this point, say so. Get Cibié ("C-B-A") replaceable-bulb headlamps, about $150/pair. Feed them properly with relays. And pick your bulbs thoughtfully; there's an enormous amount of junk on the bulb market, too. Basically, anything advertised as "extra white" ("superwhite", "hyperwhite", "whiter light", etc.) and/or with colored glass should be avoided; it's a scam.
If you've got a mountain of Money to spend, remove the mountaintop and send it to me
(and then the headlamp you want is the JW Speaker #8700 full-LED headlamp.)
Back to the land of non-mountainous money: see articles on Allpar here and here. The photos of the headlight beams on the road in both articles are very poor (photos are the wrong illustrative tool for the job), but the text is very descriptive and accurate, and although they center around parts I supplied, they were sold at normal price the same as anyone else can buy them -- no "I give you headlights, you write me a puff piece on your site" deal.
Previous threads discussing headlamp upgrades and downgrades are here, here, here, here, here, here, here, here, and here.
Headlight bulbs are pressurized to about 10 atmospheres, cold. They are designed to handle the heat and pressure resulting from running one filament at a time. They are not designed to handle the heat and pressure, nor the current on the common
filament support lead. of running both filaments at the same time for more than very brief periods during beam changeover or headlight flashing. Doing so carries the very real risk of the bulb grenading inside the headlamp, destroying it. Some people who think they're clever wire it up this way anyhow, and the "Brite Box" people have made a business out of this "clever" (not) modification. Running the lows together with the highs can only be done safely if the lows are
produced by different bulbs than the highs -- it's a common modification on systems that use a single-filament low beam bulb and a single-filament high beam bulb on each side of the vehicle, and which come wired from the factory to turn off the low beams when the high beams are switched on.
The reason why some systems come that way is to do with provisions in the US headlamp beam regulations regarding foreground light -- that is, light striking the road surface relatively close to the vehicle. If the combination of high + low produces more than a certain amount of light at a certain downward angle, then the lows have to be switched off in high beam mode (with certain exceptions, see below). Too much foreground light works against the night driver's distance visual acuity, because the brightly-lit foreground causes the pupils to constrict, reducing the amount of light entering the eye. At the same time, increased foreground light causes the subjective impression of "good" (or "better") lighting.
This is probably the prime example of how the human visual system is a lousy judge of its own performance; it's very easy to create situations in which we think/feel our ability to see is much better or much poorer than it actually is. On the other hand, factory Xenon (HID) systems, which in most cases give very high levels of foreground light, are required to leave the low beams on with the highs. That's because it takes awhile for a Xenon lamp to come up to intensity after it's switched on. If you turn off the Xenons to go to high beam, then you need to switch back to low beam, you've got a dangerous "black hole" until the Xenons come up. There are lots of complaints from owners of cars with single-Xenon headlamps (Xenon low, halogen high) that their high beams are uselessly weak. There's some basis for that complaint, but the bulk of it is because the high beams, no matter their actual performance, are rendered useless for long-distance seeing by the brightly-lit foreground on account of the high-intensity low beams. There's no right answer here, just different compromises on a philosophical continuüm. The better your low beams are, the better your high beams have to be or else the gap in their objective performance will be aggravated.
As for which headlamps to put in your single-headlamp car: Reputable-brand ones, whether you have Money to spend or you don't. If you don't have Money, get GE Night Hawk H6024NH sealed beams, about $20 apiece from amazon.com (put "H6024NH" in the search field). Not the world's best headlamps, and they're still throwaway sealed beams, but they're the world's only decent cheap 7" round headlamp. All other sealed beams are junk (because made on decrepit tooling), as are cheap replaceable-bulb units. Forget the Chinese garbage from APC, Eaglite, Maxtel, Sirius, Pilot, Adjure, and eleventy dozen other brands, and the Indian-made garbage from Autopal and Neolite. They are dangerous headlight-shaped toys that do not produce adequate performance for even creeping along at 25mph, let alone normal road speeds.
If you have Money to spend, pick your equipment carefully even though the field narrows down to about three reputable brands that are practically easy to get (there's a really nice Koito 7" round H4 headlamp, but it's costly and difficult to get). Hella and Bosch are widely available and well made of good quality materials, but their optical efficiency lags pretty severely -- this post is growing long as it is, but if you want detailed discussion and proof on this point, say so. Get Cibié ("C-B-A") replaceable-bulb headlamps, about $150/pair. Feed them properly with relays. And pick your bulbs thoughtfully; there's an enormous amount of junk on the bulb market, too. Basically, anything advertised as "extra white" ("superwhite", "hyperwhite", "whiter light", etc.) and/or with colored glass should be avoided; it's a scam.
If you've got a mountain of Money to spend, remove the mountaintop and send it to me
(and then the headlamp you want is the JW Speaker #8700 full-LED headlamp.)
Back to the land of non-mountainous money: see articles on Allpar here and here. The photos of the headlight beams on the road in both articles are very poor (photos are the wrong illustrative tool for the job), but the text is very descriptive and accurate, and although they center around parts I supplied, they were sold at normal price the same as anyone else can buy them -- no "I give you headlights, you write me a puff piece on your site" deal.
Previous threads discussing headlamp upgrades and downgrades are here, here, here, here, here, here, here, here, and here.