Re: Fog lights

[raf40@oes.amdahl.com (Richard Funnell)]

At 10:48 AM 9/7/95, Phil Ethier wrote:
>On Thu, 7 Sep 1995, wallace david wrote:
>
>> I would like to install fog lights on my 88 5000q. It looks like drilling
>> into the bumper is the only way for installation. Any suggestions on
>> placement and the brand (or Type) of lights would be appreciated. Would
>> Amber lens be better then clear?
>
>IMHO, amber fog lights are dumb.  A good fog light, properly aimed and
>mounted low enough on the vehicle, does not need to be yellow to work.
>White light is more efficient, as you are not wasting electricity just to
>have half the spectrum turn to heat in the yellow lens.  The whole idea
>is to prevent the light from bouncing off the fog and back into your
>eyes.  There are two important factors:

I would second this.  Amber lights were reportedly used because that color
was supposed to penetrate the fog better.  Tests I read a long time ago
determined that there was no real advantage, and that as Phil siad all
you're doing is heating up the lens.

>
>1. Mounting as low as possible on the vehicle.  You may get lucky and
>have the beam pass under a fog that is hovering just above the ground.  I
>have seen this happen, but don't count on it.  The real reason for low
>mounting is to have as much angle between your eyes and the light as seen
>from the fog droplets, as the droplets tend to reflect straight back,
>with the scatter somewhat less.  All around, low mounting is a win.

I'm not sure I agree with this part.  The key aspect of fog lights is a
very flat, wide beam that is *aimed* low so that it is not likely to
reflect off droplets.  It seems to me that mounting it higher and aiming it
lower would acually give a better angle to avoid such reflections, and this
was borne out years ago when I ran fog lights on my MGA mounted above the
bumper.


>
>2.  A good light has a sharp cutoff on top, and will not have scattered
>light in the fog at the level you are looking through.  Making the lens
>yellow is a cheap way to try to make up for lousy focusing.  You will
>notice that the low-buck fog lights tend to be amber.

I agree.  I believe that the beam pattern is far more critical than the
mounting height.


>
>Note that you defeat the whole purpose of fog lights if you have your
>headlights on.  Headlights are mounted too high to work right in fog,
>rain and snow.  Thanks to our brain-dead politicians that specified a
>MINIMUM height for headlights.  This also screwed up the design of my
>favorite car, the Lotus Europa, but don't get me started on that.  Many
>cars have the fog lights interlocked to require the headlights be on.
>Foolishness, IMHO.

Agreed.



Richard Funnell,
San Jose, California
'83 urQ