ULTIMATE Headlight Thread! Xenon/Halogen

[CateraMV6]

This will serve as a guide for anyone who has any questions about the Catera Headlights...



What are the most common surfaces of curved lenses:?

# clear - Gives the best down the road illumination - typically found in ECE units.

# ribbed (fresnel like) - gives less down the road illumination, bleeds slightly more light above cutoff and generally spreads light sligtly better. Typically found in DOT units

# soft - same effect as above, but will reflect some light back into reflector which means less efficiency. Found on Acura Integra (DOT unit).


This does not mean that one of the surface designs neccesarily are better than the other. A projector unit is designed as a complete unit and total quality and level of output depends on many other factors. The observations above are more interesting as a comparison if you want to tweak a projector unit.

What creates the colorful cutoff band?

It is the edge of the cutoff shield that creates the colors in the cutoff band, not the bulb. It does not matter if bulb is 3500K or 7000K, halogen or HID. The curved lens only amplifies the colors. In standard configurations, most projector units has a yellow/orange cutoff when distance to screen (=wall) is close. At longer distances, the blue color band gets appearant and sometimes even deeper in color. This would be the view that most people whatch when meeting cars with OEM HID.
The colorful cutoff band is probably what started the demand for blue bulbs in late 1990's.

Why does moving the cutoff shield change cutoff band color?

It all has to do with making the right color hit both the 60% peak and as much angle on the curved lens as possible. The further away from the center of the curved lens the beam hits, the more will the cutoff band be enlarged.
How can the blue color in the cutoff band be increased?

Moving the cutoff shield closer to the reflector will accomplish this task. This is done by pressing the shield with a finger towards the reflector. Note that cutoff will be even sharper. Moving curved lens away from shield has same effect, but will decrease output hight and width.
Can the color of the projected beam below cutoff band be altered by the cutoff shield modification?

No.
How do I optimize bulb or shield placement in a projector?

This is mostly applicable to halogen projector units upgraded with HID bulb. The idea here is to make 30-50% of hotspot rise below cutoff line. Pictured beam would be a typical E-code or harmonized pattern. The dotted circle represent the hotspot. Both bulb and vertical shield hight will affect outcome. Moving bulb or shield too much away from default position will have other negative beam consquences.
To be able to see the circle better, use one or two pairs of sunglasses. This will increase contrast between hostpot and surrounding light.





#
What path does light rays take from reflector to the road?

# foreground (2-25meters) passes high above shield edge from upper part of reflector
# down-the-road (25-90m) passes right above the shield edge from area closest to bulb
# Bi-Xenon high beam (90m and upwards) passes right above and right below shield edge from area closest to the bulb


These are photos of the actual lights European vs US...

[CateraMV6]

[Cadi Cat]

wow... after analyzing this I have realized that I think (and pretty darn sure) have the factory HID system with the European lens. Because, I know my lens does not look as it shows for the GM version and I have HID.

[CateraMV6]

Originally Posted by Cadi Cat

wow... after analyzing this I have realized that I think (and pretty darn sure) have the factory HID system with the European lens. Because, I know my lens does not look as it shows for the GM version and I have HID.

Easiest way to tell what you got is to look at the sticker on the top side of the assembly, it will either say D2S/H7 < Xenon, or H1/H7 <Halogen...
Also on the bottom side there is a carrier with the ballast and a bulky cover bolted on the assembly to protect the bulb...

As for the Line on the lens, I don't know what that does but I assume its there to soften the cutoff line, and maybe shine some light up at street signs... possibly even to spread the blue color from the projector.

BTW please post some pictures I would love to collect as much info as possible.
Thanks

[Warez]

^^^^^^^^
What do you mean by better lens material?










I bough an extra headligh and noticed this difference as well. The halogen light I have looks like the one on the R and the my HID lights are the same as the picure on the L. Is it the same there?

It is most likely just a model year change or a difference between the HID and halogen lights and not an ECE/DOT difference because both of my lights are marked ECE and DOT.

[CateraMV6]

Well both my sets have been used, the US version is so crappy that even after buffing it for about an hour it still couldnt clear the lens...

The Euro version seems to have more glass like surface, perhaps better final coating or something, different regulations have something to do with this, I know in the US, DOT doesn't allow glass for headlights, so the plastic used here is of somewhat lesser quality and after a few years in the sun it ages very badly, and causes visibility loss.. Both lights are about the same age, same road use etc... the US one looks way worse.

Now for your other question, I noticed that on the Euro lights, and it appears that some of the lost light from the lens heads down and then bounces off the bezel and illuminates straight up, towards the street signs, and I think in this case this feature is to diffuse the light and make it less concentrated or noticeable. If it was a straight piece of chrome/surface you will get some weired shapes of light, especially if you are sitting close to a garage door.

Also the Xenon lights you have probably have a nicer projector then the halogen ones, and most likely a leveling motor as well. If you are not afraid to mess with them I would suggest you crack them open and you swap out the lenses for some clear ones, make a custom curved shield and put them back together, you wont believe the difference it would make.

[gunther1000]

This may sound odd, but how about a price break down between the two and or a place to buy them?

[CateraMV6]

Originally Posted by gunther1000

This may sound odd, but how about a price break down between the two and or a place to buy them?

Thats a good one!... Price well depends on what you are looking to get.

http://www.gmpartsdirect.com/catalog/frameset.cfm

HALOGEN
Composite headlamp, catera, right, Halogen Headlamps
2001 $342.28
Composite headlamp, catera, left, Halogen Headlamps
2001 $330.25

XENON
Composite headlamp, catera, right, w/xenon headlamps
2001 $378.92
Composite headlamp, catera, left, w/xenon headlamps
2001 $378.92


eBay has a regular set of Projectors NON HID aftermarket units for 360$ shipped, so either way it sill makes for expensive replacements.

Best bet is to go search through junk yards and even those boys will charge you 100$/light for some of the decent units out there.

If your adjusters are broken its fairly easy to crack them open, remove the assembly with the projector...reglue the adjusters and put them back together.

Can be done in as little as 30min/light.