Re: Xenon HID retrofits: an optical engineer's view


"Doki" <mrdoki@xxxxxxxxx> wrote in message
news:e5ig99$msv$1@xxxxxxxxxxxxxxxxxxxxxxxx

"JB" <JB@xxxxxxxxxxxx> wrote in message
news:4e3u5dF1cv4omU1@xxxxxxxxxxxxxxxxx
I modified a pair of spare headlight units for my SO's BMW E36 over the
last week or two. Osram ballasts, Philips D2S lamps and original Bosch
reflectors with special cutoff 'masks'. The difference is simply
*astounding*. I knew they would be an improvement, but Jesus do they do
the business. Not an easy DIY conversion unless you have access to the
kit I've got at work in the lighting lab, but still not too demanding.
For a comparison, I tried a pair of these Chinese
"Sooper-Dooper-10000Kelvin-Burn yer Eyeballs Out & fry yer Ballasts" H1
retrofits which my friend had bought from Ebay for about £240. These
so-called retrofits are a cheap copy of the Philips D2S arc-tube cemented
into an H1 halogen base with heavily insulated flying leads (25kV
ignition voltage. V.Nasty). Once fitted into standard E36 headlamp, I
photometered the original 55W H1, this Chinese one, and my conversion
with a properly focussed Philips D2S lamp. Considering the 'claimed' 4x
lumen output of the Chinese lamps, they actually produced only a real
13.8% improvement in lamp lumens reaching the road surface over the
original Bosch H1 halogen units. The beam quality however was *******
and certainly illegal.
Using correctly focussed genuine Philips lamps and new masks in the same
reflectors, the improvement became 281%! Xenon HIDs do seriously *rock*.
I seem to have also gained a spare ballast and lamp too which will now be
going into my Trike's Cibie 'Z-beam' low beam unit :>).


So basically what you're saying is run 100W bulbs and don't bother pissing
about unless you want to lay down serious cash?
Unfortubnately no. 100W lamps will kill the reflector coating in very short
order. The easiest way to improve the e32/e34/e36 low beam ellipsoidals is
to use Osram Silverstar lamps. Same wattage although less lamp life, but
lots more luverly lumens. Not cheap, but well worth the outlay.
The HID conversion was for me at least, an interesting (and fairly cheap)
project. I got the £270 ballasts as 'evaluation samples' from the
manufacturer and the Philips D2S lamps from Ebay, for £25 a pair brand new.
The biggest pain was reworking the lampholders/mountings and the the new s/s
masks.

JB


.

Quantcast