Originally posted by DPelletier
You're right Duluth, when talking about different types of bulbs. That having been said, almost all the incandecent bulbs available our there, are not giving you any more light than the stock bulbs and Ty's comments on the shifting of the output in the visible spectrum is valid.
Exactly. I'm virtually certain that these are all tungsten-filament bulbs. Quartz-halogen type. The filament is going to produce the same lumens per watt, no matter what you do with the coating. Silverstars work around this by overdriving the elements slightly, that's why the burn out fast (they're putting more current through them than they're rated for, making them burn brighter).
Put more current through the filament, it gets brighter, and the color temperature goes up. These 'special' bulbs use a blue color coating on the bulb surface that shifts the color temperature up, making them
appear brighter, but the coating actually filters out a lot of the light on the yellow side of the spectrum, so you get less light output.
I'll agree that the lens/reflector assembly is the main problem here. The shapes they make these things into now, to fit the lines of the vehicle, it's no wonder they're not efficient. The old sealed-beams were much better, especially the round ones (the halogens, anyway).
If you really want more light, get the brightest bulb you can with
completely clear glass. I hear the XtraVisions, and any similar bulb, are good in this regard. The Europeans are ahead of us here, both bulb and reflector. You can get H3 type bulbs at higher wattages, but I believe the 9004 (and 9007) spec specifies the wattage, so there are no (legal) high-powered bulbs for us.
If you
really, really want more light, try a projector or HID upgrade. Neither will be cheap, and requires replacing the entire headlight assembly--you can't just put an HID element in the stock reflector.
--Ty