[Biturbos4] HID light cutoff

John AudiFans at BackYardEngineering.com
Thu Jan 19 17:54:27 EST 2006

Mark Quinn wrote:
> I love the HID lights on my A6 but hate the sharp cutoff, especially
> when going downhill or down dips when you can't see 5 ft in front of the
> car!
> I know this cutoff is formed by a motorized (for adjustment) plate. 
> What I want to know is if it might be possibly to cut slots or a zig-zag
> line in the plate to give a softer rolloff (rather than a cutoff)?  Has
> anyone tried this.  Or can anyone who may have taken their lights apart,
> comment on the feasability of this?
> Or am I just blowing smoke?
> -Mark Quinn
> 2001 A6 2.7t (various mods)

You're just blowing smoke...  ;-)  The Audi HID lights of some of the best DOT
lights I've seen. That said, they are still slightly different in beam pattern
to the ECE versions. The sharp cut off is what allows more light on the road
instead of the oncoming drivers face. It also make them good in the fog. There
is an auto-leveling mechanism, but that has nothing to do with beam pattern. I
get the impression that the DOT version is stingier on the upsweep to the right
and that most factories and dealers tend to be real conservative adjusting US
headlights. You could relatively easily and cheaply replace the HID lamp only
with the ECE version. Might not make a noticeable difference to you... We have
the same car you do and it was delivered with the low beam low enough to leave a
large dark gap between the low pattern and the high beam pattern. :-/ I
readjusted them and they're better, but IMHO still weak on the right upsweep.
The adjustment for the HID requires VAG-COM or equivalent... If you're going to
do it yourself, keep in mind a correct low beam adjustment is angled down and
still has the sharp cutoff touching the ground...  When you're playing with
VAG-COM, be sure and note the current settings before changing anything.


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