[s-cars] hid 'upgrades'

[Charlie Smith]

Earlier, Chris Covington wrote:
>
> But still guys, even if it appears your getting "good" output and
> everything lines up correctly, as per that site: (the guy I know from UM):

  [  30 more lines of hype deleted  ]

Chris - I think you are wrong.  You are quoting pages of stuff from
Daniel Stern at lighting.mbz.org.  He appears to be a self professed
expert who is really a salesman using scare tactics to say "If I'm not
selling it, it's not safe or not good".  Other stuff you are saying
is on the same theme as Stern, and you are writing lots of incorrect
generalizations.

I'm not trying to engage in an argument, and I may not even respond
to anything further based on such faulty arguments.

All I'm going to write is to expand on what I said below.

The conversion kit I described for a projector low beam puts out a lot
more light and doesn't cause oncoming traffic to flash their lights.
It is about half the price of other conversion kits being marketed.
Thus, I don't think it's "unsafe", objectionable, or feeding any
desire for large profits.

Therefore, I think it's "a good thing", and I recommend it.


As you said, placement of the light source is critical, no matter if
it is a hot filament or an arc.  At the risk of getting deep into some
techno-babel, as this list sometimes does, I'll write about optics just
a bit.

<techno-babel>

I believe it is safe to ignore the variation in light refraction and
dispersion through normal lens materials based on the wavelengths
of the light involved.  I am positive that single surface reflectors
as used in headlight systems are visible wavelength invariant.

I say this because a hot filament produces a variety of wavelengths
from red to blue that all mix together to produce "white" as perceived
by the eyes.  Normally used lens materials have to correctly refract
a large range of wavelengths, otherwise you would see a rainbow effect
in the light output, rather than white.  Light from an arc is usually
of much higher intensity, and is of a narrower range of wavelengths.
However, for the kind of light sources we are talking about, the arc
light wavelengths are most probably within the range of light wavelengths
produced by a hot filament.

</techno-babel>

Thus, I believe the assumption is correct that most lens and reflector
systems used in headlights are indifferent to type of light source.
This means that there is no intrinsically right or wrong light unit for
either type of light source.

What is important, is the light unit's ability to focus the outgoing light
in the right place with the right intensity distribution.

In this matter, my use of the term "right" is certainly subjective.

I believe you will be entirely OK if you start with a low beam light
unit that has well placed light output, and that produces a very low
level of light scatter above the horizontal cut-off line.

Using a brighter, correctly positioned, light source in this type light
unit will be entirely acceptable.

Generally, projector beam light units do a better job with output light
control that what is done by reflector light units.  I believe that if
you watch correctly focused headlights of both types you will come to
agree with this statement.  I'm not talking tungsten vs HID, just type
of headlight here.

The Audi projector low beam units do a very good job with light output
control.  Upgrading them to HID with a well made bulb will be entirely
acceptable.

    - Charlie





> On Tue, 9 Jul 2002, Charlie Smith wrote:
>
> > Chris wrote a lot about ill fitting conversion 'setups', and I agree
> > that there is a lot of bad stuff out there.

    [  8 lines deleted describing my 9006 $540 conversion  ]

> > The advantage of running this in a projector headlight is that
> > the light is sharply cut off on the top edge, so you really don't
> > dazzle oncoming traffic.
> >
> > I'm very happy with the installation I've got.