Quote:
Originally Posted by Kostamojen
Thats false, sorry to burst your bubble 
06-07 Imprezas had the same projector style halogen, as did the 05-09 Legacys. And thats just two for the sake of naming specific models, LOTS of cars have this kind of projector halogen headlight. Its just a nifty piece of glass in front of the halogen bulb. |
^^ Truth, Projector housing don't mean that the lamp is a HID type lamp. Both Halogen's and HID's can both use projector housings. HID's (Xenon's, Heavy Metal Halides, HMI's and MSR's) are the only types of lamp that REQUIRE a projector housing, both Halogen's and LED's can use plain reflector only type housings but HID's require condenser optics for focused and controlled light output. This is because HID's cannot use metal reflectors inside the lamp itself and multiple filaments to create high beams and low beams. Metal reflectors inside the lamp itself would just melt due to the high temperatures encounters in an Arc type lamp. You also cannot use multiple housings to get high and low beams, this is because of the long warm up times on HID lamps before they reach full brightness after being struck (in the entertainment industry we call it "striking an arc"). Also it's due to the fact that every time you strike (or ignite as some people say) a lamp, you lose about 1 hour of lamp life, you also cannot restrike a lamp within 10 or fifteen minutes of turning the lamp off...the lamp MUST cool to a certain temperature before it can be re-struck, unless you have what is called a "hot re-strike ballast" which is more expensive and seldom used in cars.
This means having two separate HID projector housings, one for highs and one for lows is not feasible, as the constant re-striking of the high beams would kill their lamp life as well as not being able to turn your high beams back on for 15 minutes after turning them off would not be a good thing. This is why on production cars with HID's the high beams are created by ether physically moving the lamp within the projector housing to change the lights focal point OR having a second high wattage Halogen housing mounted NEXT to the HID housing. You will notice in cars with the latter option, the high beams only add the Halogen's to the HID's and do not turn the HID's off due to the previously mentioned hot re-strike complication.
As an entertainment technician I am very well versed in the area of lighting
-Trev
Entertainment Lighting Tech