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Headlamp FAQs

From gti-vr6-owner@dev.tivoli Sat Nov 29 23:51 CST 1997
From: collinsk@pacbell (Kevin Collins)
To: gti-vr6@dev.tivoli (GTI-VR6 Mailing List)
Subject: Fw: Headlamp FAQ
Date: Sun, 30 Nov 97 05:49:38 GMT
>From r.a.m.v.w... good info for those who may not have seen it there..
Kevin Collins
&#99;ollinsk&#64;pacbell<img src=/i/dn.gif border=0 width=35 height=15>
'97 GTI VR6

--------------------------Forwarded Message------------------------------

Oops.  It seems that a truncated and misattributed copy of my Headlamp FAQ
v. 2.2 has been circulating.  I am, in fact, the author of that article
(not the "slowcarfastbike" named at the bottom of the faq) and am
happy to answer any technical questions about vehicle lighting and
signalling.  I also supply E-code headlamps and serious auxiliary lamps
(Marchal, Cibie, etc.) for almost any vehicle you can think of.  Below is
a fresh copy of the Headlamp Faq v. 2.2   This document is available with
nicer formatting at

Headlamp Technology FAQ v 2.2
Copyright (c) 1997 Daniel J. Stern &lt;&#100;astern&#64;ursula.uoregon<img src=/i/de.gif border=0 width=35 height=15>&gt;
May be distributed on the Internet (excluding use on WWW pages without
permission) provided this copyright notice and author's name and E-mail
address are kept intact and included.

 Upgrade your Headlamps!  So--you say your headlamps aren't satisfactory
and you'd like to upgrade them, but you're not sure what to do?  Or
maybe you've burnt-out or broken a headlamp and want to make sure you
get the best replacement available.  Read on--you have lots of options.

Here is a description of the various headlamp systems available, their
benefits and drawbacks:

Tungsten (non-halogen) sealed beam headlamps
Advantages:  They're inexpensive.  You can pick them up for between $3 and
$9 most anywhere.

Disadvantages:  They're extremely dangerous. At 50 mph on a dry day, you
are out-driving them.  They produce a very dim, unfocussed, tunnel-shaped
pattern with very little light to the sides of the roads.  Backglare in
rain/snow/fog is extremely debilitating.  Light output specifications for
these lamps have not changed since 1956.

Next, there are halogen sealed beams

Advantages:  They're still relatively inexpensive.  They go for between $6
and $20 most anywhere.

Disadvantages: All of the disadvantages of the normal sealed beams are
still applicable, because these throw the same beam pattern and offer only
a very slight increase in candlepower over normal sealed beams. Halogen
sealed beams also are the shortest-lived of all automotive headlamps,
making them economically questionable in the long run view.  Light output
specifications for these lamps have not changed since 1977.

Replaceable-bulb, aerodynamic USA-spec ("DOT" is on the lens) headlamps

Many people incorrectly assume that these aerodynamic lamps are the same
as the lamps in use in Europe.  This definitely is not the case!  The
USA-specification aerodynamic lamps can be identified by the word "DOT" on
the lens.  They use a 9004, 9005, 9006, or 9007 bulb (also called HB1,
HB3, HB4, and HB5).

Advantages:  When the headlamp burns out, you need only replace the bulb,
not the entire lamp assembly.  Also, automotive stylists like these lamps
because they can make them any size and shape they desire.

Disadvantages: These lamps are subject to the same beam pattern- and light
output-restrictions as sealed beams (above).  In many cases, the light
output of these lamps is much worse than even the relatively dim
illumination provided by sealed beams.  Often, the lenses are made of
inexpensive plastic which looks OK on the showroom floor, but which
quickly degrades, becoming cloudy and yellowed.  This further reduces the
meager light output from these lamps.  It is interesting to note that
senior veteran headlamp engineers at Carello, Hella, Valeo-Cibie, and
Osram-Sylvania are on record as stating that the US aerodynamic headlamps
are among the worst, most dangerous developments in worldwide auto
headlamp technology in the last two decades (formerly this dubious honor
was held by the 4" x 6" small rectangular sealed beam).

"What about overwattage bulbs for my US-spec aerodynamic lamps?  Won't
they help?"
If your headlamps have plastic lenses and/or plastic reflector
housings, you cannot use these bulbs without creating a serious fire
hazard and causing extensive (and expensive) damage to the headlamp
assemblies in short order.

Even if your headlamps use glass lenses and metal reflector
housings, you still cannot safely use these bulbs because the wiring in
DOT-spec headlamp systems is not capable of handling the level of current
these bulbs will draw.  If you disregard this and do it anyhow, you create
several serious fire hazards in the engine compartment and, more
worrisome, in the passenger compartment at the headlamp switch.   This
problem could be circumvented with the installation of an extra-heavy-duty
relay and heavy wiring, but the next problem is going to trip you up:

The 9004, 9005, 9006, and 9007 bulbs used in DOT-spec headlamp systems all
have extremely small electrical contacts.  Go ahead and have a look;
they're really spindly!  These contacts get extremely hot even under
normal (45 to 65 watt) loads.  They get dangerously hot under higher (80w,
100w, etc.) loads.  When you go much above 65 watts, these contacts become
the point of maximum resistance.  Things start melting and burning, and
(here's the kicker) you will not achieve any improvement in your
headlamps' ability to light-up the night.  No reputable bulb manufacturer
makes these overwattage DOT bulbs for that reason.

The ones you may find are third-rate junk that not only will not last very
long, but which also do not have the tight filament geometry and placement
tolerances that good bulbs have, further compromising your lamps'
effectiveness and safety.

Even if you could find overwattage 9004, 5, 6, 7 bulbs with oversized
contacts and ceramic bases, make your wiring adequate to handle the extra
load, and be sure your headlamps contain no plastic, you *still* would be
wasting your time and money to use the overwattage bulbs, because the
optics and beam pattern specified in such headlamps by the DOT does not
respond to overwattage bulbs.  I know that it sounds overly simplistic and
vaguely impossible, but it absolutely is true.  It's a moot point,
however, because such "Beefy Bulbs" do not exist.

Next, the replaceable-bulb E-code headlamps.

What does "E-code" mean?  It's a quick way of referring to a
European-specification headlamp. The "E-code", signified by a capital "E"
in a circle on the lens of the lamp, signifies that the lamp has passed
the rigid ECE tests for light output, durability beam pattern, etc.  These
lamps are required in most of the driving world, and permitted in most
other places.

Advantages: Much higher light output than any sealed beam, but with a very
well-focussed beam pattern.  Illuminates very widely so you can see to the
sides of the car.  Seeing distance on low beam is easily 2.5 times better
than sealed beams, about 3.5 times better on high beam.  Low beam pattern
is less offensive to oncoming traffic because of careful focus control.
Backglare in bad weather is completely eliminated.  How do they do this?
The beam pattern, instead of being a fuzzy blotch, is a wide "bar" with a
sharply-defined upper cutoff.  The cutoff sweeps up to the right to
illuminate road signs.  You see the *road*, the *obstacles* and the
*signs*, not whatever might be falling out of the sky towards the road.
The light, even with stock wattage bulbs, is much whiter and more useful
than the light from a sealed beam.  The increase in wattage is not
sufficient to cause electrical problems. They are available to replace all
sizes and shapes of sealed beam lamps, and can also be obtained in the
aerodynamic models for later-model cars. They drop right in and plug right
in place of your current lamps. They are built to last for decades, and
their construction reflects (sorry)  this.  Sturdy steel housings,
computer-designed and laser-cut lead crystal lenses, vaporcoated aluminum
reflectors, silicon seals.  The bulbs last a long time, and can be
replaced in a minute. Stock-wattage bulbs from quality manufacturers
(Osram, Philips, GE, etc.) can be obtained most anywhere; prevailing price
is $4 to $6.  Specialty bulbs in higher wattages and/or with a dichroic
coating to facilitate visibility in poor weather can be obtained easily
and, in most cases, used safely.


1) Cost.  They cost significantly more than any sealed beam.  This is
explained by the quality of the construction materials (see above) and the
fact that they are meant to stay in use for several decades, because you
need replace only the bulb, not the whole unit.  The aerodynamic
late-model E-code headlamps usually cost about the same as their USA-spec
counterparts.  Note that some late-model aerodynamic E-code headlamps are
not suitable for use with drastically overwattage bulbs.

2) Legality.  This is an issue only if your vehicle is subject to
inspections that involve the use of a mechanical headlamp aimer. NJ, PA,
VA, and MD have historically tended to
 be stickler states in this regard, but I have several reports that NJ and
PA no longer check for DOT headlamps, but merely
  ensure that both headlamps come on when you turn on the switch. Can
anyone confirm or refute this?  Most states dropped this antiquated
methodology in the 1960s.)  If you take your car to such an inspection
with E-code lamps, they will not be able to use their aimer (they lack the
three little pips on the front of the lens that are for this aimer to
attach to) and will squawk at you. 

Note that many US headlamps no longer use the on-the-lens aiming pads, but
rather have a calibrated scale and a levelling bubble that is visible if
you open the hood.  The European lamps for these applications also have
these items, so aimability is maintained and nobody ought to know or care
that your lamps are not US spec. 

For those with large (7") round and large (7" x 6") rectangular sealed
beams, There is a replaceable-bulb lamp available that does have the
provisions for such aiming equipment, enabling even those in NJ and PA to
get many of the benefits of the E-code lamps without the inspection
hassle.  The inspection-ready lamps, however, are not as good from a
performance standpoint as the other available E-code lamps.  While they
certainly are better than sealed beams, they cannot equal the full E-code
conversion lamps. 

As far as on-road legality goes, there are really no worries, you won't
likely get stopped for your lights if they are aimed correctly.  Remember,
they are _less_ offensive to oncoming traffic, so it's not as if you'll be
pissing people off as you drive along. 

"Nice theory, but what about the real world?  Will cops target me because
of my E-code lamps?" 

Of course, I cannot guarantee that it won't happen.  Have I ever been
pulled over for having non-USA headlamps?  Absolutely never.  I've driven
with these lamps in four different cars in 14 states, including the full
length of California, Oregon, Washington, Nevada, Utah, Wyoming, Idaho,
Colorado, Montana, Illinois, etc. and have absolutely NEVER raised the
attention of any cops, even when I drive past them with my lights on. And
the car I drive most often is using special dichroic bulbs that cast a
very strong *yellow* light, which is clearly a non-stock light color.  I
still have never had a problem.  The fact of the matter is that back in he
'70s when all cars had sealed beams, E-code lamps stuck out like sore
thumbs.  But today, with the proliferation of so many different headlamp
designs, together with the elimination of headlamp inspections in at least
48 states, nobody knows or cares what kind of headlamps you're running,
especially if they don't glare at other drivers. 

If you live in the US states of Oregon, Washington, Alaska or
Massachussets, or in the great nation of Canada, then E-code lamps are
100 percent legal and none of these concerns apply to you.

Projector-beam (or "DE") headlamps:
The projector-beam headlamp functions rather like
a slide projector, using a plano-convex lens to distribute the light,
rather than a parabolic aluminized reflector. They must produce the
same light patterns as every other lamp and conform to the same intensity
requirements as every other lamp for whatever compliance system (DOT,
E-code, whatever) they're built to.  They offer new stylistic
possibilities, and they can be made to give a sharper cutoff (useful in
E-code setups), and they can be field-switched between left-dim and
right-dim (useful in Europe) but those are the only inherent advantages.
Now, there are sometimes implementation advantages.  That is to say that
sometimes, cars were available with either parabolic-reflector headlamps
or DE/projector headlamps. And sometimes the DE headlamps for that
specific application work better than the parabolic reflector headlamps.
But this is very application-specific, and does not indicate that one
technology is superior to the other. (In other words, in the same
comparison, sometimes the parabolic-reflector headlamp wins.)

High-Intensity Discharge (HiD or Xenon) lamps:

These lamps are coming as standard equipment in some expensive cars.  They
are not currently available as retrofit items.  Nonetheless, here is some
discussion on the topic:

It's amusing to see people running around trying to ascribe all kinds of
magical benefits to these lamps.  Claims run from the plausible but
not-quite-true ("They're nine times brighter!") to the completely
implausible ("They let you see three times further!") to the ridiculous
("They'll insulate your house!  Filter your coffee!  Win friends and
influence people!")  The *fact* is that the chief benefit of these lamps
is that they consume less power than normal lamps to generate the same
amount of light.  Current production HiD headlamps consume about 42w each
instead of 45-55w each, which is the current consumption of low-beam
halogen headlamps.

While the system is designed to last the life of the
car, components are *extremely* expensive should anything go wrong.  And
the controller is a one-use-only item; if you're in a collision, it shuts
itself down permanently so as not to shock rescue workers (we're dealing
with an extremely high voltage system here.)

There is another, more insidious disadvantage to these lamps:  The light
they produce is very high in blue and green wavelengths.  This is
trumpeted by the marketeers as "producing light similar in color to
natural sunlight", and it makes the light *appear* brighter to the human
eye, which is a nice bonus in dry weather.  However, this is a
double-edged sword, because these blue and green wavelengths reflect most
readily off of water droplets (rain, fog, snow...) which means that with
the HiD lamps, backglare in inclement weather is greatly increased.  This
is much less of a problem with European-specification lamps, in which the
low beam pattern is required to have a sharp cutoff with very little
above-horizontal light.

Unfortunately, the US DOT continues to demand inferior lights with lower
output and a much less distinct cutoff.  There is lots of stray light
above the cutoff on all lamps on cars sold in the USA, which increases
this backglare effect.

In Canada, both ECE (European) and DOT (American) headlamps are
permissible, so a blanket statement cannot be made about the degree to
which this glareback effect--also present in DOT halogen lamps--would
manifest itself.

The important thing to remember is that both ECE and DOT headlamp
specifications have very strict limits on headlamp intensity.  HiD lamps
are not granted exemption from these limits, so claiming that they're
"brighter" is not necessarily true.  Often, specific implementations of
HiD lamps come closer (often much closer) to the legal limits for light
intensity, and in these cases it IS accurate to say that those specific
lamps are brighter than their incandescent equivalents.

Note that some hucksters have begun selling halogen bulbs dipped in blue
paint of one description or another, describing them as being "just like
the xenon lamps in Mercedes".  Nothing could be further from the truth.
These hand-dipped bulbs are not approved by any regulatory agency anywhere
in the world and decrease the performance of your headlamps.  Wagner,
Sylvania, Osram and Philips are pursuing legal action against the
marketers of these phony-blue bulbs, not only because some of them have
been using those company's trade names illegally, but also because these
reputable companies understandably wish to distance themselves from this
kind of Beavis-and-Butthead cheeseball product.  I spoke to product line
managers and lamp engineers at each of these companies, and they all were
horrified at the concept of these bulbs.  You're well advised to STAY
AWAY.  Philips is marketing a line of dichroic-blue coated bulbs in Europe

As a side note, don't confuse actual Xenon (HiD) headlamps with the
halogen bulbs from Wagner that are sold under the tradename "Xenon
Britelite".  These Wagner capsules and sealed beam lamps are no different
from regular halogen lamps.

In 1996, a "Harmonized" beam pattern agreement was reached to come up with
ONE beam pattern that is acceptable to the regulatory agency in Europe as
well as to the clueless regulators here in the US.  The beam pattern
closely resembles the European beam pattern, sometimes with modifications
(such as having a stepped-up portion of the beam instead of an angled
upsweep).  This is great news for purchasers of new cars in the coming
years, as more and more cars come equipped with these harmonized or "dual
approved" headlamps.  And it's great news for those of us who use E-code
headlamps, because it makes our technically unapproved headlamps very
difficult to distinguish from the beam patterns emitted by brand-new cars.
Alsready in 1997, there are lots of brand-new cars on the road with what
amount to modified E-code headlamps: '93 Volvo 850s, '94 and later Saab
900s, some Audis, some Mercedes, Honda Civics, Odysseys and the new
Accords...the list is only going to grow.  

This FAQ continues to grow because of your questions.  Please feel free to
contact me &lt;&#100;astern&#64;ursula.uoregon<img src=/i/de.gif border=0 width=35 height=15>&gt; with any lighting and signalling
questions you may have, or if you'd like to discuss upgrade optios for
your vehicles.  I handle the European Cibie, Marchal, and Hella lines,
among others. 


Daniel Stern &lt;&#100;astern&#64;ursula.uoregon<img src=/i/de.gif border=0 width=35 height=15>&gt;
Automotive Lighting Specialist and Consultant
E-code headlamp conversions, side turn signal repeaters, etc.
Cibie, Hella, Bosch, Marchal, etc.  -->Below Retail<--

Contents of this message Copyright (c) 1997 Daniel J. Stern, all rights
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