IML: Headlights

["Eric" <gearhead@xxxxxxxxxxx>]

About the blinding headlights thread on the list, improper aiming is one of 
the leading causes of glare from US spec headlamps. Being that the US 
government mandated a fuzzy beam pattern for US lamp manufacturers in years 
past, these lamps were notoriously difficult to properly aim, as well as 
providing minimal lighting. The European standard, known as E-Code beam 
pattern, has a sharp cutoff of the light beam that is dipped for oncoming 
traffic, and specific aiming points for proper aiming.  Many US States have 
specific codes which allows for such types of improved lighting equipment.
As I understand it from the material I've come across on the subject, 
halogen sealed beam lamps actually provide slightly less light than the 
sealed beams that came originally in our cars. The whiter light is what 
helps the recognition of the roadway being lit.
Obligatory Imperial content: If one were to use replaceable bulb lamp units, 
ie non sealed beams, and were to up the wattage of the bulbs, this would put 
a larger electrical load on those Imperials with the previously mentioned 
rocker style headlamp switch if a relay isn't utilized in the system, 
increasing the likelihood of eventual switch failure.
A preferred lighting upgrade would include a relay installed into the system 
and an upgrade of the headlamp to a more efficient design, such as Cibie's 
Complex Reflector style of lamp, so that a standard wattage bulb can be used 
while increasing the effective light on the road.
Now to some headlamp basics: To get the light from the bulb to the road, the 
typical process of the old style of headlamp is to reflect the bulb's output 
off of an unsophisticated, flat surfaced  reflector bowl, then through a 
highly bevelled glass lens which shapes the pattern of the beam. The flat 
surfaced reflector bowl has some inefficiencies in that is has cold spots 
and hot spots based on the characterists of the bulb's filament shape, with 
no means to capitalize on the hot spots. As well, relying on a highly 
bevelled glass lens to shape the beam pattern produces inefficiencies of 
it's own.
The Cibie' CR lamps have a reflector backing that is shaped/bevelled to make 
maximum use of the bulb's filament's hot spots of output specific to the 
bulb's placement in the lamp bucket. Being that the beam pattern shaping is 
now done by the complex design of the reflector backing instead of relying 
on a highly bevelled clear glass lens, there is greater efficiency of light 
travel through it's relatively simpler lens.

Ok, thats probably more than anyone wanted to know, but when I read of 
people upping bulb wattage, I can't seem to restrain myself. For those 
interested, more on these lamps can be read here 
http://dsl.torque.net/products/csr.html  I have a set, they provide a more 
even light dispersion as well as more light when compared side by side to a 
replaceable bulb E-Code lamp bucket from Hella with matching bulbs. I run 
standard wattage bulbs and never get any high beam flashing from oncoming 
motorists as they are aimed properly.

Eric
'63 Crown Four-Door
'72 Newport Custom sedan 



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