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View Full Version : HID upgrades

01-06-2003, 04:01 PM
Jeff, is it safe to install stage 1 or 2 in 99 540 with halogens?

01-06-2003, 05:31 PM
The glass lenses inside your OEM assemblies aren't pattern-matched for the Xenon bulbs. I don't know the exact issue, but I've heard you should replace the lowbeam lenses if upgrading to Xenon. Also, you should check to see if you'll need the resistor packs (see link below).

There are folks on the E39 board that might have their Xenon-spec assemblies laying around after upgrading to CELIS assemblies, so you should post there if interested or to get more info on the pattern matching. If you had money to spare, a very popular option is to buy the Xenon CELIS assemblies with bulbs and ballasts from places like HIDS4LESS, which is what quite a few of us have done.

To specifically answer your question, I'm running Stage II on my '97 E39 just fine.<br><p>
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Mr Grean
01-07-2003, 11:42 PM
Before you spend your money you MUST read this and go to the website for further details.

Converting to HID

So you've read about HID headlamps and have it in mind to convert your car. A few mouse clicks on the web, and you've found a couple of outfits offering to sell you a "conversion" that will fit any car with a given type of halogen bulb, for between $900 and $1300. STOP! Put away that credit card. Trying to "convert" halogen headlamps to HID is an unsafe thing to do. There are *NO* legitimate or safe HID retrofits for the headlamps of any car which didn't have HID lamps as a factory option. Here's why:

HID (High Intensity Discharge) headlamps use an arc capsule where an arc jumps between two electrodes. This arc is used as the light source, instead of a glowing filament. Not only is it very important to have the light source (filament or arc) at exactly the right spot in the reflector for the lamp to produce a proper beam, but the source (filament or arc) must also be oriented correctly--either fore-and-aft, or side-to-side, depending on the design of the lamp. In addition, headlamps that produce both a high and a low beam must have a bulb with not one, but TWO filaments, each of which must be very precisely located and, in the case of some low beam filaments, shielded. In this game, fractions of a millimeter count! The only way to assure the correct placement of the source in the lamp is to use the correct bulb type. Most people don't realize this, however, and there are some unscrupulous types, placing their wallets before your safety, who make a buck off of your NOT knowing how crucial it is to use the correct source in your headlamp.

These "conversions" generally consist of a headlamp bulb base that has been drilled-out, with an HID arc capsule crammed in and glued. Sometimes instead, there's a semipermanent adaptor plate that fits where the bulb would go, with the HID arc capsule fitting inside of the plate.

There are no HID arc capsules that have more than one arc (i.e. high beam and low beam in one capsule, as found in 9004, 9007, H4, HB2, and most all sealed-beam headlamps.

There are no HID arc capsules that have a transverse (side-to-side) arc path. 9004 headlamps and most all sealed beams use transverse filaments.

Even if we consider replacing a single-axial-filament bulb with a single-axial-arc capsule, these so-called conversions are unsafe. The quantity and nature of the light put out by the arc is quite different from that of the filament, and the reflector and optics of a halogen headlamp are not designed to produce a proper headlamp beam with anything but a halogen bulb. Even assuming the arc position were perfectly matched-up with the filament position, the nature of the light from an HID capsule is such that the resultant beam pattern will usually produce very much excessive glare to oncoming drivers and backdazzle to the driver in bad weather, and will fail to illuminate properly the places in the driver's field of vision that really need to be illuminated.

The folks pushing these "conversions" assure their customers that it's not particularly crucial to get the source position exactly right. I'd like to think that's because they simply don't know any better, that they consider any piece of glass with light coming out a "headlamp"...rather than to think that they're simply placing their personal profit over your highway safety.

Perhaps most dangerous of all, these "conversion" pushers casually dismiss the fact that if you install one of their "conversions" in a system where the original headlamps produce both a high and a low beam, you will not have a high beam after the "conversion"! The pushers claim that a high beam is "not necessary" with HID headlamps. This is certainly quite wrong both from a legal perspective and a safety perspective. A low beam headlamp, no matter how bright, is a low beam headlamp, and cannot substitute for high beam.

Now for the technical nuts 'n' bolts for those who want to know exactly why it won't work.

"Retrofitting" an HID arc capsule in place of a filament bulb is a very poor idea. There are lots of folks out there advertising "retrofits" of this type. In a nutshell, it is sometimes possible to physically adapt an arc capsule to go where a filament lamp was meant to go. It is really NOT possible to attain an acceptable (let alone compliant) beam pattern this way. Some of the "retrofits" get kind of close with regard to cutoff gradient and relative light levels within the beam, but most all of them have beam problems...improperly placed hot spot, dark spots in the center of the beam, excessive foreground illumination, excessive stray (glare) light, improper cutoff placement, etc.

It is, as I say, sometimes possible to place the arc in the headlamp exactly where the filament was located before. However, an arc is a fundamentally different *kind* of light source than a glowing filament. The reflector and/or lens optics in a headlamp meant to take a filament lamp are designed specifically for the characteristics of a glowing filament.

Many optic designs rely on the edges of the filament to shape the beam pattern, for instance, and there is no reason for chromatic correction to be worried about, because in most filament-lamp headlamps, chromatic aberration is not a problem. (Some polyellipsoidal optics do exhibit substantial prism effects at the cutoff.) The boundaries of the arc in an automotive HID capsule are much "fuzzier" (to use a technical term!) than the edges of the filament in a filament bulb. There are substantial color differences at different points in the arc (the edges, the ends, etc.), while the color of a glowing filament is relatively uniform. The arc is usually not the same length as the filament. For all these reasons, it is not reasonable to expect an acceptable beam pattern just because the arc is placed in the same location as the filament was.

Note that this does not even address the issues raised in lamp designs in which the filament is not coaxial with the bulb base (9007, NDF/9008) or in which the filament is transverse rather than axial (H3) or transverse AND non-coaxial (9004). All arc capsules (D1, D1S, D1R, D2, D2S, D2R, 9500) have axial arc paths that are coaxial with the base. This does not stop "headlamp mercenaries" selling "conversions" for such headlamps. The resultant mess cannot be called a beam pattern, but as long as the "converted" lamps spray-out lots of purplish light, the purchasers of such "conversions" tend to be happy, not knowing and/or not caring that they are driving with dangerous, overly-glaring, inadequately-performing headlamps. ESPECIALLY if the seller of the "retrofit" has given ill-informed (or just plain fraudulent) assurances that the kit is "beam pattern corrected". There's flatly just no such a thing!

Most people do not have the expertise (let alone the equipment) to judge the acceptability of a headlamp beam pattern. Most people can tell the difference between arc light (purplish) and halogen light (not purplish). It is certainly possible to physically place an arc capsule into a halogen headlamp. But for all real purposes, it is NOT possible to make an acceptable headlamp this way. For some cars, legitimate HID retrofit kits are available. These consist of complete new headlamp lens-reflector units to go with HID capsules and ballasts. This is the *ONLY* safe and proper way to put HID headlamps on a car not originally so equipped.

01-08-2003, 10:40 AM
In either case, some of what Mr. Grean is correct some is not. We use injection molding in most of our applications. In your particular application your better off upgrading H->Xenon Angel Eyes with Resister Packs, because you get that new projector with the D2S bulb. This is going to give you the best results.


01-08-2003, 06:29 PM

Please let me know what is not correct in Mr. Grean's post. I can't find anything wrong with it. Very informative and factual. Excellent post.


<br>Joseph (1985 M635CSi)
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01-29-2003, 08:59 AM
to HIDs. As an electrical engineer working in optics for over 25 years, I can assure you that everything in the above post is true.

It takes an incredible amount of design engineering and quality manufacturing to get well-controlled light distribution, repeatably.

Fortunately, most BMW E39 drivers will recognize that quality is not just in buzzwords, but is in (optical) performance.

Now if we could only get auto mfrs to quit putting those faux-PepBoys round rear lights everywhere... what a crazy fad! (JMO)

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