Tech Article: Everything You Want to Know About Headlights, But Were Afraid to Ask.

by John Harris,
J.B. Enterprises

I had previously written an article on aiming your headlamps. The following information is more pertinent to the H4 style headlamp bulbs. Also included with this new headlamp info is a discussion on headlamp beam patterns and use of H4 headlamps. The following information is provided by Group Z and ZCSD member JOHN HARRIS. We thank him for allowing us to use this information. JOHN HARRIS is an authorized Autopal dealer and sells the H4 headlights and bulbs with applications for all the Zs. He can be reached at (310)518-6514.
- Ben Pila, Member-at-Large


Do you need special headlights?

Have you ever had the impression that you are going to fast for the lighting conditions? This is called "Over Driving" your lights. By using H4 headlights this is virtually impossible because the low beam throw is almost 1,200 feet and the high beam is over 5,000 feet. If you drive with these lights once, you’ll never want to be without them again. You will find H4 conversion headlights to be one of the most important safety devices on your car. Please check your state laws regarding light limitations.

Two-headlight system

Low beam features: broad even illumination forms a "blanket" of brilliant white light. Flat horizontal beam cutoff eliminates stray light, prevents blinding glare. 15º right-hand rise in the cutoff reaches out even further to pick up signs, pedestrians, cyclists, etc.

High beam features: long range penetrating beam creates "environmental daylight effect. "Gives you plenty of time to react to changing road conditions, Eliminates dangerous "overdriving."

What is a beam pattern?

The beam pattern is the shape of the light as it’s projected from your lamp.

Why is it so important?

Since different beam patterns allow you to see different things, the beam pattern is the most important characteristic to consider when selecting your lamps. It’s so important, in fact, we’ve named several of our lamps by the shape of their beam.

Where does the shape of the beam come from?

The lens is responsible for spreading the light into a computer calculated beam pattern developed for specific driving conditions. An intricate prism configuration on the inside of the lens bends the light to the needed degree as it passes through the glass.

Since truly effective non-glaring illumination can only result from precision beam control we put a lot of emphasis on the production of our lenses. They’re all made of the finest clear glass having optimum light transmission properties, and they’re checked with a laser beam for optical accuracy. This is a very costly process, but with a component as important as our lens, we just can’t afford compromise. Don’t forget, with ineffective lighting you’ll pay the really high cost of poor visibility.

How do you know which beam pattern is right for you?

We understand that all this beam pattern terminology can get confusing. So we’ve put it all together in this handy comparison table. It will show you just which beam pattern is right for your kind of driving and the light that have that type of beam.

INFORMATION FOR H4 HEADLIGHT ASSMEBLIES

Aiming: Lights can be aimed accurately with an optical aiming machine. They can also be visually aimed by shining them on a large flat surface, (i.e. wall or garage door). Place the vehicle on a flat level surface, 25 feet from aiming surface, making sure vehicle is normally loaded and the suspension is settled.

Low Beam: The correct visual aim for low beams is with the top edge of the beam cut-off 3" below horizontal. The point at which the cut-off begins to rise to the right should be located straight ahead of the lamp.

High Beam: The correct aim for the high beams is with the center of the high intensity zone at horizontal, straight ahead of the lamp.

H4 Bulbs: Replacing the H4 bulb requires removing the rubber boot, releasing the tension on the spring retainer and pulling the bulb out of its base. Inset the new bulb, by holding onto the base, retention spring retainer and reinstall rubber boot to make a good seal.

If you handle the bulb, avoid touching the glass portion of the bulb. This Will Result in Premature Bulb Failure! Should you accidentally touch the glass, clean the area thoroughly with alcohol and cotton before lighting the bulb.

The service life of H4 bulbs is greater than that of ordinary bulbs when supplied with a constant voltage through clean, low resistance connectors. Excess voltage can cause premature failure of H4 bulbs, low voltage is equally bad because it does not allow the bulb to reach operating temperature necessary for halogen recycle. Vehicle voltage should remain between 12.5 volts and 13.5 volts with all electrical devices functioning at the same time. Avoid starting the vehicle with the headlights on, especially in cold weather.

Please Note: Some applications, i.e. General Motors, Volkswagen, etc. require the relocation of the spade connector location. This will become obvious, if both high and low beams light up at the same time or one does not light up at all.

XB3 Xenon Boosted Blue Bulbs

The new XB3 bulbs offer a 30 to 40 percent increase in perceived light as a result of a new coating material that actually increases the color temperature and moves the light closer to daylight.

These bulbs require no wiring or modifications of any type.

This new bulb conforms to all DOT regulations as well as all ECE R37 (European) regulations.

By coming closer to a daylight color, these new bulbs allow the brain to actually process more of the information the eye receives from the roadway ahead of the vehicle. The color of the light matches the "sweet spot" of the eye, and thus more information is transmitted to the light processing area of the brain.

A significant percentage of road accidents occur during poor driving conditions caused by weather and darkness. Visibility needs increase with age. Compared with a 20 year old, a 30 year old required 50% more light, a 40 year old twice the light and a 50 year old three time the light.

Because these bulbs are standard OW wattages they are ideal for use in vehicles that my be sensitive to an increase in current draw.

For additional information, please feel free to call me at (310)518-6514.