[s-cars] Questions about the 9005 bulb "trick"

[Kirby Smith]

The projection system in the Audi urS6 works by putting the field mask
at the lens focus (more or less, its not that well corrected) and
projecting the light that passes over the field mask down into the far
field.  Any light that passes that boundary and hits the lens helps.
However, even a perfect mirror on the inside of the mask may not
materially add light to that passing over the field mask.  One would
have to trace rays to find out.

The heat hazard is not to the lens, but to the plastic parts in the
assembly, especially the mirror coatings on the reflectors.

kirby

A Ma wrote:
>
> Hi Dave,
>
> I've been running this trick for about a year now. I think if you pool
> enough 9005/6 bulbs from different manufacturers together you'll run into
> some that match perfectly and some that will be off by a mm or so even among
> the same bulb type. As to the ceramic cap, I don't think the glass projector
> lense will be greatly affected by the extra heat, especially with the
> cut-off shield. As to stray light, the cut-off shield should make the cap a
> moot point. Just make sure your lights are properly aligned.
>
> As a question to the list in general, I'm considering lining the inside of
> the cut-off shield with aluminum foil or something equally reflective to
> "recover" some of the light lost by the shield. I realize that it will
> result in stray light but I'm curious as to where and how much. Any comments
> about this or btdt?
>
> Alvin
> 93S4
>
> >From: Dave Forgie <forgied at direct.ca>
> >To: s-cars <s-car-list at audifans.com>
> >Subject: [s-cars] Questions about the 9005 bulb "trick"
> >Date: Sun, 02 Mar 2003 11:11:50 -0800
> >
> >Being of Scottish ancestry (i.e. frugal) (forget the sheep jokes - those
> >are for the New Zealanders), I am interested in the trick where a 65W
> >9005 bulb is modified to fit in the 9006 (55 W) low beam position of the
> >OEM DOT headlight housings.  I have down loaded the "More_light.htm" for
> >the BMW E34 website and have checked out my spare 9005 and 9006 bulbs
> >and have two questions:
> >
> >1.  The difference in the position of the filament in the two bulb types
> >is about 1 mm.  Is this going to cause and problems, i.e. the beam being
> >out of focus??
> >
> >2.  The OEM (say Hella) engineers obviously were thinking about
> >something regarding the ceramic cap on the end of the 9006 low beam
> >bulb, i.e. heat on the projector lense, focal points, stray light, etc.
> >What are the downsides of no cap on the end of the 9005 65 W bulb?
> >
> >Dave F.
> >
> >
> >
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