Chuck540MZ

The April Consumer Reports Magazine has an interesting article on HID or Xenon lighting for cars. Other than the Mamby-Pamby complaints of those who whine about HID's because they're jealous they don't have them, the article did point out these facts:

- Blue lighting, whether halogen or HID, causes more glare to oncoming traffic than white light, even if the white light is brighter.

- HID bulbs put out 3 times the light output of halogens while using 1/3 less energy and lasting much longer.

- Because halogen lighting does not have as sharp of a "cut-off" as HID lights, they produce a more gradual shift from light to dark so that other drivers are not "flashed" as much when the car travels over uneven surfaces.

- HID lights channel more light to the sides than halogens.

- 6/10 vehicles with HID's and 9/31 with halogens reached a 400-foot marker when tested by CR, BUT, a halogen-equipped Mazda Protege5 hit the 600 foot marker while an HID-equipped Audi TT could only manage to light a 200 foot marker.

- HID bulbs with halogen-style bases (as sold by most HID lighting outlets), violate federal standards, because halogen reflectors aren't designed to properly direct an HID bulb's greater light output.

Having recently converted my Acura MDX over to HID's using the "contraband" halogen bases (9006), I can see why they could cause some issues with other drivers. I tested the stock halogens first on a wall by marking the cut-off and pattern, then I did the same after installing the HID's. By just changing the bulbs, the pattern and cutoffs changed completely while the light output to the side increased dramatically.

After adjusting the aim of the lights I was able to get the pattern somewhat close to the stock halogens, but it was still much different and a LOT brighter, so I aimed them extra low to be safe. I still get the odd "flash" at night on the highway from oncoming traffic (maybe 1/100), but this is about the same as I get with my 540 which has properly aimed xenons and self-levelling. HID's may not be made for my MDX light housings, but the light output is amazing and I think well worth the $400 cost (bulbs and igniters).

Seattle Scott

As a potential Audi owner you need to learn not to mention the Devil's magazine. CR only understands toasters. Car parts and cars are far beyond their comprehension. They obviously rigged the test so the Audi TT would fail. Another example of the injustice we all suffer from "The Man" at CR. ;-)

audiconvert

I believe that because the HID lights are a plasma arc created between 2 electrodes they will never mimic the same illumination source of a tungsten filament in a halogen bulb. So what you have is probably a line source of certain distance as opposed to a more single point source that a tungsen filament produces. Because of that you can never optimize the reflected beam of a halogen-to-HID replacement because the reflector wasn't designed for such a long light source. ...just my thoughts.

Edd W

because a Halogen filament is mounted horizontally in the centre of elipsoidal reflector. So the light source is very accurately located to work with the reflector shape and lense design. The light produced by the HID type lamp is more of a rugby ball shape, longitudinally in the centre of the reflector, so the light is emmited from a larger source, that is not the same precise distance from the back of the reflector.

The only answer really is to fit the full kit and do it properly, although it may be possible to lower the lights enough, you still do really need the self-levelling.

In time the conversion kits will improve, but then most cars will start getting HID fitted as standard.

Most Mazda, Toyota and Honda, as well as GM, Renault, Peugeot, Ford etc... all fit them as standard over here now on the higher spec models.

Driving at night on the motoway, you now seem to see about 10-15% of oncoming traffic has them.

TeddyBGame

<ul><li><a href="http://www.intellexual.net/hid.htm">HIDo's and HIDon'ts - great article.</a></li></ul>

Chuck540MZ

WOW! That is a great article. Thanks!

5speed6 v.2

Yes, the 5-series has always dominated all car rag tests, but "POO POO"....some editor must have been sitting in a Saturn ION when he wrote that.

They each have their fine merits, and usually it's in the steering feel and handling where the 5-series edges out the Audi. Fit, finish &amp; interior design, both German designed &amp; equally rated. Exterior, most editors prefer the design of the Audi over the BMW. Quattro...'NUFF SAID !!

phred

The cutoff with HIDs is very extreme. The quality of light is better but they don't have much range.

carbonLORD

Ted, great article. Thanks much!