HID/Xenon Lighting Conversions

(this information has been collected from many site's FAQs and compiled here to explain the conversion process)

I am sure most everyone is familiar with HID lighting. Most of us have seen them on the road. That extremely intense white light that makes the rest of our Halogen headlights yellow and dark by comparison. Probably the same sentiments people had before Halogen lighting came to market.

I guess a small definition is in order for those who don't know what HID is or maybe you just want to familiarise yourself more with the system and how it works.

Unlike Halogen lamps, High-Intensity-Discharge (HID) lamps do not generate light by heating a tungsten filament inside a capsule filled with halogen gas ( the gas helps prevent blackening of the capsule as the filament slowly burns out). HID lamps operate more like vapor-filled streetlights. They don't have a filament, but create light by zapping an arc between two electrodes. That arc excites a different kind of gas, usually Xenon, which in turn ignites metallic salts. The light produced by a HID Xenon lighting system is greater than a standard halogen bulb and with less power consumption. On the road, HID Xenon lighting systems appear as a bright white beam which resembles natural daylight. The most common cars seen on the road today equipped with HID Xenon lighting systems are Mercedes Benz, Lexus GS400 and LS400, BMW 3-7 Series, Porsche 911, and the Lincoln Mark VIII.ð

A 35 watt HID lamp produces up to 3 times the lumens at the light source when compared to a standard 55 watt Sylvania Halogen lamp. A 55 watt Halogen lamp draws a constant 10 Amps, while an HID lamp in steady state draws in 6 Amps (35-40% less power). As a result of lower power consumption, less heat is dissipated by the HID lighting systems and more power from the engine. An HID lamp will last three to five times as long as a halogen lamp. For most people, this translates into the life of the vehicle and probably the life of the next vehicle as well.

The light color of a light source is expressed as color temperature. The higher the color temperature of a light source, the light emitted will run through a scale from dark red, red, orange, yellow, white to light blue. The higher the temperature, the whiter the color. Xenon HID light sources for automotive use are rated at 4000-4500 K while halogen bulbs are rated around 3200 K. As a reference, natural daylight is rated at around 4500-5000 K.

It's not just a matter of dropping HID bulbs into your existing car. Standard 12 Volt DC automotive power sources are incompatible with the HID lamps. HID lamps run at approximately 25,000 Volts and require 20 Amps to start up. Once the HID lamps reached its steady state, power consumption is only 3.5 Amps at 35 watts and 75-80 volts. That's why eachð HID Xenon bulb requires a ballast/controller.

HID conversions can generally be installed into any car that uses a headlight design where the bulb can be replaced independently of the headlight assembly. Beam pattern correct HID conversions can only be done on headlights which use a bulb that satisfies all of the following conditions:

• The bulb is a single filament bulb (i.e., the low beams and high beams use separate bulbs)
• The bulb has a axial filament (i.e., the filament is parallel to the length of the bulb, rather than the width)
• The physical dimensions of the bulb are similar to the physical dimensions of the HID light source.

If your car has a dual filament bulb (low and high beams combined into one bulb), a conversion may still be possible, but it is probably not possible to correct the beam pattern. In addition, you will have to to give up your high beams. This is because HID is designed as a low beam only system. All HID systems in production use separate bulbs for low and high beams, with the high beams being standard halogen bulbs. Because of the startup time required for HID, it may be unsuitable in instances where you need to flash your high beams. All factory equipped HID systems use the dual bulb HID low/Halogen high configuration. I do not recommend or endorse a loss of high beam conversion, mainly due to the incorrect beam pattern that will result. An added drawback to a loss of high beam conversion is the fact that should the HID system fail for any reason (usually improper installation), you could be left with no lights at an inopportune time or place. While it is possible to perform a conversion and retain the high beams, this requires extensive modifications to your headlight housing or a custom headlight housing to be made. Both options are very expensive, but if professionally done, the conversion will have a corrected beam pattern. As a side note, any vendor that tells you a beam correct conversion can be done on a 9007, 9004, H4, or 9003 without custom headlight housings is either not being truthful with you, doesn't fully understand the technical issues, or hasn't actually tested it. It is interesting to note that combined low/high HID systems are currently in the prototype stages. The feat was accomplished by actually moving the HID light source back and forth inside the headlight assembly to alter the focal point from low to high beams.

As for cars that use a bulb with a transverse filament, while a conversion may be possible, the beam pattern results may be unpredictable due to the fact that HID light sources are only made with axial arc paths. Again, in this case, for a beam pattern correct conversion, extensive modifications will need to be made to the headlight housing or a custom housing made. Thus, I don't generally recommend axial filament conversions.

OEM HID systems have self-leveling motors on them and have a european-style pattern reflector to genrate a sharp beam on the road. Self-levling devices alone cannot correct glare.ð If your current headlamps do not produce a crisp and clean beam pattern, HID retrofit may not be effective. Some headlamps are prone to glare regardless of light source (HID or halogen). Hence, glare should be taken into consideration.

Most kits include 2 direct plug-in HID Xenon bulbs, 2 base adapters, 2 ballasts, 2 igniters,ð matching wiring harnesses for PLUG and PLAY, complete installation instructions, and wiring diagrams for custom installs. These kits are made for do-it-yourself installation for anyone who is comfortable with electrical wiring. Kits are ready to install and designed for plug and play. A typical installation takes 1 to 1 1/2 hours.

The conversion kits are not DOT certified. Thus, it's not street legal for use on public roads in the US. Unlike factory equipped HID headlamps, retrofits without self-leveling housings and automatic headlamp washers may cause glare. Therefore, the companies can officially endorse it for exhibition and off-road use and will only sell it to be used for these purposes.

When I do my conversion, I already have the crisp european pattern with my Golf 4-look lights. In Europe, there is an option on the Mk-3 VWs for a headlight leveling system. This is bascially two motors that plug into a socket in the European spec headlights to lower the pattern of the lights downward if the car is under load. This is controlled though the headlight switch on the dashboard, just to the right of the dashlight dimmer roller. If I can just figure out how the self-leveling works on the cars already equipped with them, I shouldn't have much problem doing the same for my own car.

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