Originally Posted by XJDesertFox

Found this on redline forums posted by Omega_5 and found it to be an awesome writeup

It's become apparent that there are a lot of people who go out and buy HID's without knowing what they are getting into. Basically, they are throwing cash away. So hopefully this thread helps.

Projector vs Reflector
Now, as some of of you may have noticed there are a few of us that tend to complain to many members about putting HID's in factory halogen reflector housings. Most of you don't understand why.... maybe this will help.

First lets compare the light output.
Your factory halogen system is anywhere from 550 lumens to 1100 lumens.
HID kits range from 1200-3500 lumens; the 4300k bulbs being the most light output, and the purpley 10000+k systems dipping down to 1200 lumens.
It's easy to see here, that a decent HID kit will produce nearly 3 times the light as a regular bulb.

Now, lets compare the housings.
Reflector housing are made to push the light in one direction. They do the job, but you can't control all of the light output of a bulb. You can get glare at the ends of the output light. It's caused by scattered light hitting a point on the reflector, that it wasn't supposed to hit.
See the left image below.

Projectors, on the other hand, take all of the reflected light, and focus it on to a projection lens. This controls the end of the output a bit better... The disadvantage though, is that a projector will put out light on in the upper directions as well. A cut off shield prevents this. It limits how much light is sent to the top of the lens.
See the right image below.


Now, what is glare?
The glare I refer to is a beam of light directly hitting a persons eye.
I'm not talking about looking at the beam from a side or any of that... I mean right at the eye.
The reflective glare from some lights is similar to looking directly into the headlights.

Now I hope we all understand why we don't put HID's in reflector housings.
If you haven't got the point yet, here it is in simple terms.
After a conversion, your light will be 3 times brighter.... so will the glare.
Glare is what causes 'sun spots' in people eyes at night. A headlight light can cause reduced visibility for a while, but a very bright glare can actually temporarily blind a person. Not good if your the other driver.

What about cars that have OEM HID reflectors?
Yes, some cars, such as Lexus IS300's come from factory with HID's in reflector housings. We have to understand a few key points about this though.
1) The housings are specially designed for HID's, as to optimally cut down on HID glare. These aren't just your everyday run of the mill housing. Although they don't have a sharp cut off, they control where the light is being emitted to.
2) They use special bulbs; D2R. The D2R bulb has certain sections painted out on the bulb to reduce certain problematic glare areas. Also, D2R bulbs produce less light than the bulbs found in projectors.

How does this affect me?
Do you want to be the cause of an accident? Didn't think so.
There have been numerous reports in the across the US and Canada of accidents being caused by temporary blindness. What do you think was the cause? PnP HID kits.

Now it's a matter of time before the cops start cracking down on this.... and I sure hope they do.

Then what is the right way to do it?
Projector housings, or better yet, a retrofit.
You can buy projector headlights for under $250 now. They have dedicated low beam projectors, with pretty good cut offs in them. They are available from many retailers, and even on eBay.
A retro fit is indeed the best option. It basically consists of taking apart your headlights, and hacking the reflector housing to fit in a projector from a dedicated HID vehicle, like a TSX, FX35/45, or a BMW. It's actually the cheaper route in the end, but takes a lot of time. A retro can take anywhere from 12-26 hours of work, and many more hours of planning. Most retro's cost about $150-$200, plus the HID kit (bulbs and ballasts).
On a separate positive note, many newer factory HID projector are 'bi-xenon'. They have an adjustable cut off, to allow hi and lo functions on HID. Ex) Infiniti FX34/45.

So, that's the bottom line.
If you are still hell bent on a PnP ghetto kit, that's your deal.... but don't cry if something bad happens. (I've heard stories ranging from 'the cops ticketed me' to 'some angry motorist smashed my headlights')

Bulbs

It's apparent that many people have a misconception about bulbs, lumens, and kelvin.
So, lets clear this up right now. The higher the Kelvin, the less light output you get (lumens).
With that said, anything over 6000K is basically a waste.
So, what is the best bulb? IMO the 4300K is the best, as it has the highest light output. The problem, though, is that they have a yellow-ish tinge to them that some people find un-attractive. In that case, 5000-6000k is a better choice for you..... as they have a more blue look to them.
As you can see below, 4100k has almost the same color output as natural daylight.

(Image from HIDPlanet)

And a few comparisons of Kelvin color;










And a comparison of Kelvin to lumens;
Standard OEM halogen 55W 9006(HB4) = 1100lm (lumens)

4300k D2S Philips = 3200lm (lumens)
4300k D2R Philips = 2800lm (lumens)
4300k D2S Philips = 2400lm (lumens) actually 5800k
4300k D2R Philips = 2000lm (lumens) actually 5800k
4800k D4S/R (brand) = 3800 (lumens) -- brightest in the market
5800k D4S/R (brand) = 3300 (lumens)
7000k D2S other = 1790lm (lumens) *(other bulb brand)
7000k D2R other = 1390lm (lumens) *(other bulb brand)
8000k D2S other = 1180lm (lumens) *(other bulb brand)
8000k D2R other = 780lm (lumens) *(other bulb brand)

Higher than 8000k, the light output significantly drops off, causing the light to be almost useless.

One should point out that although light output drops off after 8000k, the fact that the light is in the blue-purple spectrum, it still puts a major strain on the eyes of others.


Now, it's also important to understand the 2 main types of bulbs used by the OEM's.
There is D2S, which is designed for projector housings. The bulb does not suppress any of light exiting the housing, as the projector controls that.
The D2R bulb, however, has a portion painted. This is because they are commonly used in reflector housing specially designed for HID's. The painted section controls the problematic glare sections that arise when using a reflector housing. As you may have noticed, from the above chart, the D2R has a lower light output.


And finally, for anyone searching for information on HID's or lighting in general, here are some important terms to know:
(Thanks to HIDPlanet)
Watt- Measure of electrical power (w)
Volt- Measure of electrical charge (v)
Kelvin- Measure of color temperature (K)
Lumen- Measure of light brightness (lu)
Capsule- technically correct term for a HID "bulb".
Candela- Measure of light intensity (cd)
Ampere- Measure of electrical current
Cut-off- A distinctive line of light produced by the shield in a headlight that blocks light above a certain height in order to prevent blinding of other motorists.
Beam Pattern- The pattern of light that is projected onto the ground which includes angle of lateral dispersion, width and depth of illumination.
Capsule- Another term for an HID bulb. Some refer to HID bulbs as gas discharge capsules.
Optics- The lighting control assembly structured around the bulb, which effects the dispersion of light and it's characteristics to a great degree.
HID (High Intensity Discharge)= Gas Discharge
Halogen= Incandescence

Originally Posted by bayer-z28

As far as the K2 lights and eBay projector setups (I have K2's with 8000k's), I have NO clue why it says "Not for HID bulb!" HID's "burn" cooler that stock headlights but maybe it has something to do with the setup.

Originally Posted by VIP1

Here is a good primer I've posted a few times:

HID = High Intensity Discharge
Its a bulb and ballast assembly. Instead of a filament glowing in a glass tube (incandescent & halogen), HID is a arc of electricity at a high voltage in a glass tube.

Projector Housing
Its a light housing with a reflector "bowl" in the rear, cut-off shield in the middle, and curved glass focus in front. It produces a wide even light pattern with a sharp flat or stepped line with light below and little to no light above. Some projectors are halogen, some are HID.

Reflector Housing
Standard incandescent & Halogen housing with a reflector in the rear and either Clear or Fresnel or Parabolic glass in front. The cut-off and general pattern is not as well defined as a projector. There is no cut-off shield. The beam pattern is determined by the glass pattern and reflector shape. Almost all reflector housings are halogen or incandescent. Only a couple HID reflector setups were available from the OEMs.


Check out the Lighting FAQ for some more info on Headlight upgrades and projectors. HID Planet's Forums is also a great place for information.


You shouldn't install HID in the High Beam location because they can't be flashed quickly. You'd loose the ability to signal other drivers with the high beams. Vehicles that come from the factory with HID high beam have Bi-Xenon projectors. Its one projector housing for low beam and high beam with a movable cut-off shield. For the high beam, the cut-off shield rises to let more light upwards like a standard high beam pattern.


Here are some examples of bare projectors:


(Not my hand.)


Here is an example of a projector beam pattern:

(My 2001 Formula with Hella 90mm H9 projector, modified cut-off, and 4300K HID kit.)
(Since this pic was taken, I've upgraded to 55watt 4500K and made some adjustments to the custom shields for better output.)


(tadpole's Miata with FX35 projectors)

(Please note that those pics were not taken at the same place or settings so you can't compare brightness. That being said, the FX projectors are brighter, wider, and have better spread than the Hella 90mm.)

Here is some good reading:
http://www.danielsternlighting.com/t...nversions.html
http://www.danielsternlighting.com/t...e/bad/bad.html
http://www.danielsternlighting.com/t...good/good.html

Some good discussion here:
https://ls1tech.com/forums/appearanc...un-around.html


Regarding HID Kits:
Basically Halogen and HID produce light differently (glowing filament vs. arc of light) and HID kits don't always place the arc in the same place as the Halogen filament. And some halogen filaments are horizontal to the glass tube. All HID arcs are vertical in the glass tube. Which means that the focal point will be off and you'll get a bad light pattern. Also, HID puts out a lot more light than Halogen. Therefore a Halogen Reflector Housing intended to spread a certain amount of light of a certain shape over a certain area now has a lot more light going outside this area not necessarily where it is needed and often where it shouldn't be (high, blotchy, and often into the eyes of others).

This problem becomes compounded with dual filament hi/lo applications. I've seen four kinds of so-called "bi-xenon" HID kits designed for dual filament applications:
1.) One fixed/non-movable HID capsule
You lose high beam but its position and resulting pattern is like the high beams are stuck on and you are blinding everyone.
2.) One HID capsule for low beam and One Halogen bulb for high beam attached to same base
Neither is positioned correctly and the high beam bulb is not replicable. Sucks for you if it blows.
3.) Two HID capsules on one base. Neither is positioned correctly and you have way too much light coming out for high beam and you can't flash-to-pass because HID starts up slowly and you can damage the bulbs and ballasts from frequent flashing.
4.) One Movable HID capsule often with a built-in shield/cap. This is the "best" of these options because it tries to put the arc in close to the correct position for high/low operation. The capsule will move depending on whether you have the high or low beam activated. The beam pattern is still not good, but not as bad as the above options.


For clarification, a bi-xenon projector has only one fixed/non-movable HID bulb. When high beam is activated, the cut-off shield inside the projector moves to allow more light higher through the lens.


Check out the Lighting FAQ: https://ls1tech.com/forums/showthread.php?t=710357

The K number is the color temp. It is not the brightness (well not directly, I'll explain). 4000K - 5000K is the brightest. Continuing up the color scale, the light gets bluer then purpler and the lumen output (the actual measurement of light) decreases. In other words, a 10000K HID kit is dimmer than a 4300K HID kit. Our eyes are least sensitive to blue light. Blue light also scatters more easily. In the end, we can see better with 4300K HID for many reasons.

For the 1993-1997 Firebird, you'd need a bi-xenon setup otherwise you'd lose high beams.

Originally Posted by The Mighty Texan

So if i understand correctly, and this would be for the sake of our cars headlights, our "reflector" housings arent designed very well but it goes unnoticed with halogen lighting because they are a weaker light, and when you pop in the HIDs the lighting is much better but so is the glare. Projector housings fix this to collect all light to one spot. So, its not that HIDs make reflector housings worse, its just that the brighter output makes the flaw (glare) brighter as well.