croatoan

I have a 2007 A6 with HID headlights. The brightness is weak (nothing like those in the new S4 I test drove the other day.) The service writer said he installed a new bulb in one of the headlights, and, if anything, the new one was actually WEAKER than the original (although he does acknowledge that the lights appear weak to him.) He claims there's nothing that can be done. Is this possible? I don't want "blue" or "purple" lights, I just want the original HID'S to be bright as they ought to be. Any suggestions?

DirtyVegasTT

Perhaps the Kelvin rating was different on the new S4 coupled with a different projector assembly? I would find out what Kevlin rating you currently have and try to get HID bulbs that best match the natural light. I really liked my 5400K bulbs back on my BMW - really good clean white light, no blue.

BVegas

Our lights are a little dim too.... (HID, the ones that move left and right around corners) . This is on an 05 A6 3.2 quattro. I only notice it when I drive the A6 and then my new land rover back to back -- the LR3's lights are amazingly brighter. I'd be interested in anyone else thinking that their A6's lights arent as bright as they used to be.

uberwgn

Bulb fatigue is fairly minimal over time. However, they do seem to change color as they accumulate hours.

I've driven a lot of different cars fitted with HID. The Audi A6 (C6) is towards the lower end of the scale compared to other cars I've been in. However, they're certainly not alone in this category. It seems that HIDS are not created equal.

chuckee98

HID bulbs creep up on the Kelvin scale as they accumulate hours (get whiter). For that reason, it's recommended to: 1. Replace HID bulbs in pairs to maintain light balance. 2. Replace the burnt out bulb with a higher Kelvin rated bulb (ie: 5000k) to approximate the light balance in relationship to the existing.

FWIW, this would not be the first time that I read that Audi HID headlamps are lacking in brightness and definition. Honda S2000 HIDs supposedly are superior to most.

zzz4

Changing the bulbs should not be a big deal. There is a lot of fear about them but they can be bought cheap ($35 for a pair from HIDEXTRA.com) and changing is not a big deal either.

I think the optimal frequency is around 5,500K and I think the OEM comes in 5,000K. Otherwise, the lights may look cool (or ricy if you ask me) but the illumination will suck.

gIzzE

Our 535d sport touring had amazing lights, there was a real arc of light ahead if you, the A6 are not as good as this but I have never been left wanting.

chuckee98

IIRC, OEM is either 4300k or 4600k. Not sure.

The G Man

All US oem HID is around 4300K by law, its the optics that make some lights look whiter than others.
HIDs will get whiter as they age, they will also get weakeras well, if I remember right, after 3 or 4 years of normal use, its down to 70% or 80% of power.