atrus5

Will someone please direct me to a good explanation of the differences between Audi headlights. I know that these are not unique to the Audi, but I'm looking for a high-level explanation of "projectors", "e-codes", "HID", "Xenon" that I keep seeing tossed about. I think that projectors and e-codes are more related to the lenses or housings and the HID and Xenons are bulb technology.?.?

How do I determine what my 2001 Audi A4 Valeo headlights are? I'm in the U.S. which I believe is a factor.

I'm sure this sounds like a pretty simplistic question to many but I just bought the Audi used and this is my first non-American vehicle.

Thanks

n0yxl

But it looks as though the link is dead?

<a href="http://lighting.mbz.org/faq">Understanding Headlight Technologies</a>

At any rate, you can google headlight technology and get some good info there. Also theres a few other HID type lighting articles in the AW tech section which are good reads as well.

TristanP

Projectors and reflectors are one of the two main types of <a href="http://en.wikipedia.org/wiki/Headlamp#Optical_systems">headlight designs</a>.

HID and Xenon are used interchangeably to describe <a href="http://en.wikipedia.org/wiki/Headlamp#HID_light_sources_.28Xenon_and_Bi-Xenon.29">high intensity discharge</a> bulb systems (the very white to blue/purplish lights you typically see on luxury cars).

E-codes are the european version of the projector lamp design with a much sharper beam cutoff.

I know for sure that HID/Xenon headlights were an option for the '01s (since I have them) and possibly the '00s. I could upgrade to e-codes and transfer my ballasts and bulbs for a slightly better beam pattern. Those without factory HIDs can upgrade both the bulbs (from halogen to Xenon) and the lens assemblies (from DOT spec to e-codes).

IIRC, there are four possible combinations:
DOT halogens (US standard equipment)
DOT xenons (US factory option)
e-code halogens (Euro standard equipment)
e-code xenons (Euro factory option and the best combination)

Someone please correct me if I got any of this wrong.

atrus5

Thanks for the good writeup. That does help. I printed it out to use as a cheat sheet.

(I'm embarrassed to admit that I could not find my thread and figured I must not have posted it correctly until just now.)

atrus5

Thanks, I saw the tech articles, but I needed even more basic information. What TristanP provided really helped since I didn't even know which way to slice it up.