So my 98 GS400 has just under 170k miles on it now, and i recently put in HID foglights. So to match them, i ended up picking up a new set of HID headlight bulbs (8000k, thanks Baoser!). So, as we all know, the higher the kelvin rating, the lower visible light you actually get. Stock bulbs are rated at about 4500k or so? And i just put in 8000k headlight bulbs.

Well my question is, does light output actually decrease over time from HID bulbs? Because i have a ton more visible light from these 8000k bulbs than the stockers. They light up the road a lot better. So im curious if anyone else has experienced this?

 

they do begin to fade but it's very gradual and not for a long time...

long time = depends on usage obviously but probably around 2-3 thousand hours.

 

The color gives you the illusion of seeing more, but it's actually dimmer.

 

how many hours per year would you say a person would have their headlights on, under normal conditions?

 

for me personally.. probably close to an hour a day or so on average. some days 2-3 hours, some days none. so.. the car is almost 10 years old.. thats like 3000+ hours..

 

yep the color makes you think its brighter, you can use the light meter and you can find out for sure.

 

Im pretty sure that the main reason you are thinking that your HID fogs are putting out more light is because they are closer to the ground, the light source is not far above the ground (whole purpose of foglights) because fog is always a few feet off the ground,

HOWEVER, blues actually are worse, the higher in temperature you go the lower the output, because our eyes do not respond well to that color. On light colored pavement, the blue may "stand Out" but do not confuse this with output.

CHange your HID bulbs with new D2R, and I would not get anything above 6000k, anything above that is really for show, and your are missing out on the benefits of HID. ANd you will see a big difference,

I have had 2 98 GS400's one with HID and one without and let me tell you that those old HID bulbs are not bright, the halogens outperformed them easily. Yea they were a "cool" purple color, but it was because they were old and color shifted

Brand new OEM HID is 4300k, a old colorshifted bulb is probably 5000-6000k

Your fogs if you would have got them in 3000k/4300k/6000k they would be brighter, especially with 3000k/4300k

But I think in this case your fogs appear brighter because they are closer to the ground, also because you have old bulbs, not really because the color.

Swap them with new ones, I would go 4300k-6000k TOPS, you should see a pretty big difference

 

wait.. so the HIDs that you had were factory or aftermarket conversion kit? because i'm a little concerned about the color shifting. this doesn't make any sense to me because HIDs are supposed to be 3x brighter & last 10x longer than regular halogens.. so for you to tell me that "the halogens outperformed them easily" is like breaking the laws of physics.

 

it was a 98 with factory HID, bulbs were just really old and tired

They are 3x brighter new, with all new ballasts and bulbs, but old no way its 3 times brighter. Long time member on HIDPLANET, guys will tell you on there, that HID if not maintained properly, or fitted with the incorrect bulbs will be outperformed by a good halogen setup.

Plus the headlights in the halogen were brand new, old ones were replaced due to moisture, on top of that they had those silverstars/ultrastars.

They were pretty bright, and also the nice white color, stood out and lit up the road helluva lot better than the purple from the colorshifted bulbs.

id say both cars with the fogs on were about the same, maybe the HID had a little more width, but as far as visible light goes the Halogen was lighting up the road better

 

well okay.. as long as HIDs last a lot longer than halogens i should be ok.. spending $90 after ten years isn't so bad that's about 90 cents a year.. haha