Re Headlights

[gosnell]

Firstly are the headlight glass pattern the same for inners and outers, if so as it has been suggested I was tinking of using H4 bulbs on both lamps so that the wattage at high beam is the same for both lamps, but it is obviouse when on dipped the inner won't have a supply so it does not matter that the inner is fitted with a duel element bulb.


John

 

[Dave3066]

Hi John

I've just looked at my own car and the glass is different. Not sure what you're getting at though? If the inner has no supply on dip then it won't matter what effect the glass has as it won't be on :? Unless you're talking about modifying to a 4 dip lighting set up, which has been covered previously.

Dave

 

[gosnell]

The thought behind the question was if all 4 lamps have the same glass light pattern what affect will there be , for example if all lamps have the glass that are ment to be main beam what affect will there be on dipped

 

[Dave3066]

The thought behind the question was if all 4 lamps have the same glass light pattern what affect will there be , for example if all lamps have the glass that are ment to be main beam what affect will there be on dipped

I see now :idea:

If all 4 lights have the same glass lens pattern as the inners then you would not get a true dipped beam as the lens forms part of the focussing process, along with the reflector and the offset filament in the bulb.

In true Loreal fashion, here's the science bit:

"The traditional European method of achieving low and high beam from a single bulb involves two filaments along the axis of the reflector. The high beam filament is on the focal point, while the low beam filament is approximately 1 cm forward of the focal point and 3 mm above the axis. Below the low beam filament is a cup-shaped shield (called a "Graves Shield") spanning an arc of 165°. When the low beam filament is illuminated, this shield casts a shadow on the corresponding lower area of the reflector, blocking downward light rays that would otherwise strike the reflector and be cast above the horizon. The bulb is rotated (or "clocked") within the headlamp to position the Graves Shield so as to allow light to strike a 15° wedge of the lower half of the reflector. This is used to create the up-sweep or up-step characteristic of ECE low beam light distributions. The bulb's rotatory position within the reflector depends on the type of beam pattern to be produced and the traffic directionality of the market for which the headlamp is intended.

This system was first used with the tungsten incandescent Bilux/Duplo R2 bulb of 1954, and later with the halogen H4 bulb of 1971. In 1992, U.S. regulations were amended to permit the use of H4 bulbs re-designated HB2 and 9003, and with slightly different production tolerances stipulated. These are physically and electrically interchangeable with H4 bulbs.[20] Similar optical techniques are used, but with different reflector and/or lens optics to create a US beam pattern rather than a European one."

Hope that helps

Dave