Max_A6

Ok, typical situation: HIDs colors don't match. Checked headlight markings - one produced 07/00, another - 09/00, apparently original. Checked bulbs - aha, bluer is Philips D2S, yellower - Osram Xenarc. OK, bought new Philips D2S bulb (ebay, $40), installed - damn, it's yellow as well. Puzzled, I swap the other (bluer) Philips with old Osram - and Osram is blue as well.

So, $40 discovery is that it's not tne bulb, it's ballast. STFA, ballast doesn't come separately. But is there a way to tweak the existing?

thomas1978

Re: HIDs (=xenons) and xenons = problems thank god my car doesn't have xenons

technokid

but rather its your projector housing. A ballast cannot, as far as I know, affect the color appearence of the bulb, all they do is send enough voltage to the bulb to ignite the gas mixture. It is most likely the projector its self.

Do both prejecotrs produce the same colors at the cutoff line when both of them are using the philips bulbs?

Oh, and new bulbs take time to color shift. Thats why its best to change xenon/hid bulbs in pairs, imo. They are relatively cheap on ebay compared to the dealer. Philips have been known to be whiter than Osram bulbs, as far as D2S bulbs are concerned. The older the bulb, the less lumens it will output, and the bluer it will get because of colorshift. Xenon does last forever, but they do age as well.

You can buy a D2S ballast on ebay as well. Though i doubt thats your problem. Ballasts are sealed, no way to "tweak" as far as I know.

duodallas

The color depends on the mercury content in the lamp. The more mercury, the yellow it gets, but the brigher it is overall, and there's a warm-up effect, etc. To avoid infringing on each other's patents, the bulbs probably have different amounts of halide and mercury, so their colors when warm will be slightly different. Tha ballast will not change that.

Max_A6

It's definetely not the bulbs. Either bulb - Philips or Osram - produce bluer light in pass. headlight and more yellow in the driver's. I swaped them to make sure.

technokid

all the bulbs are producing the same light in the same projector, though what duodallas says is correct, the actual color output of just the bulb by itself depends on the salt contents in the bulb and how much color shift has occurred.

Your projectors may have small enough optical differences (say, in the lense, the projector reflector bowl, the cutoff shield, etc) to make the light appear different between the two projectors.

What you can do is try to fire the bulb outside of the projector; just connect it to the ballast and make sure the ground return wire doesn't touch anything. This way you can see the actual color differences or lack thereof between the bulbs. Older bulbs will be bluer because of colorshift and newer "standard 4100K" bulbs will be whiter (Philips uses 4100k as standard, and Osram uses 4300K as standard iirc, however, I have noticed that Philips bulbs [85122] are both brighter and whiter than osram). It is very bright, so dont look directly at the bulb.

TeddyBGame

great dialog guys....good info. I'm bookmarking this thread.

Max_A6

Both bulbs are Philips D2S. Camera actually exaggerates the difference slightly:

<img src="http://pictureposter.audiworld.com/48084/audi_xenons_front.jpg">

The following comparisson is not quite accurate as the door is white and the wall is beige:

<img src="http://pictureposter.audiworld.com/48084/audi_xenons_wall.jpg">

I recall that when I've bought the car 2yrs ago I found the wiring entry in the driver's headlight was lose, it didn't seat tight. Probably this caused some oxidation on reflectors inside. I think I'll stop my exploration here, I don't think any further effort is worth it.

P.S. Here's bi-xenon by bmw. Same Philips D2S bulb, but newer design with bigger lenses makes them much better. Not to mention cool "aiming" feature.

<img src="http://pictureposter.audiworld.com/48084/bmw_xenon.jpg">

duodallas

different amounts of blue due to dirt or chemical changes. There's a fair amount of UV light coming from these bulbs.

There is a very slight change in the bulb's CCT as it ages (tungsten deposits on the bulb interior), but I don't think it's noticable to most people.