RotorNutFD3S

iTrader: (33)

This is turning into an interesting thread.

I caught this little part. If you use the projectors I did, you are immediately limited to 35w systems. People quickly found that the 50w systems started melting things on these projectors. Not because the projectors are cheap or brittle, but simply because they weren't designed to handle the amount of heat the 50w systems produce. Some also found out that the cheap eBay HID kit bulbs put off a ton more heat than a quality bulb and we're having issues as well. So just FYI. There's a ton of good knowledge on HIDplanet.com, before I did my retrofit I read and researched in those forums for a couple of days.

soloracer

iTrader: (10)

Is there any real work involved in doing this with the Moss kit, or is it just a matter of bulbs? This is what I would like to do if I could get my hands on a Moss setup for a reasonable price.

JasonC SBB

Agreed. But assuming that the HID Bixenon solenoid moves the arc's center when going from low to high beam properly to the proper centers of the 2 filament positions, then the only other variables are:
- the shape of the light source (of which I said the HID is a bit fatter in the middle, maybe 3 mm wider)
and
- the accuracy of the shade

Regarding the shade, think about the shape of the shadow an H4 would cast if it's placed in the middle of a sphere. Now design an HID shade that sits outside the capsule, so it casts the same shadow. Not too hard.

As for the width of the light source, I pointed out that moving a halogen lamp side to side by about 2 mm blurs the low beam demarcation line indeed, but doesn't hugely increase the scatter above said demarcation line (which is what causes glare).

Note that if the light source width were a real issue, a halogen projector design would suffer from the same increased scatter when HID capsules are installed. (Projector designs combine a reflector and a lens, in order to have smaller headlights with greater light captured and sent forward. The reflectors in projectors would have the same size of focal point as reflector-only designs) However, this doesn't seem to be the case. Note that halogen projectors appear to have less scatter built into them than typical reflector designs.

I suspect that the reason we see OE's using projectors for HIDs, is because they moved to projectors (using halogens), *before* HIDs became common.

I still stand by what I said, that the scatter is a function of the reflector design. The scatter is there whether you use a halogen bulb or an HID capsule.

As for the extra nasty HID-in-reflector patterns shown, that's probably a function of:
- poor light spot location accuracy vs a halogen
- poor shade design

I suspect that the quality of the HID bulbs is variable, and the VVME I use is pretty decent. This may be why there are so many crappy patterns out there, and yet AbeFM and I think our setups are "OK". This is different than concluding "all HID setups in reflectors will have awful scatter"

RotorNutFD3S

iTrader: (33)

I agree. Look at the older Acura RLs (99, 00, or so), they don't have projectors but came with HIDs from the factory and have a very nice beam. I've never looked at the reflector closely though.

Joe Perez

iTrader: (8)

I was thinking the same thing.

On the very low end of the scale, this might consist of little more than a plate which bolts into the stock headlight housing in place of the stock sealed-beam unit, which has a provision to mount a projector similar to the one linked to earlier. It's possible that depth and waterproofing might be issues, but I expect something like this could be made to work.

Personally, I'm thinking back to the idea that bounced around some time ago where somebody had taken a set of eBay-sourced clear-lens turn signal assemblies, gutted them, and installed halogen lights inside- the idea being to use them as the main headlights. I'm wondering if an HID projector assembly this small might be able to fit in such a configuration...




This first assumption is where my thought process diverges from yours.

If the arc center of the HID lamp is located in the space which is precisely between where the two filaments of a halogen H4 would be, then right off the bat we do not have a "proper" positioning of the light source. If we want the pattern to be identical to what we'd have with a halogen light source, then the entire HID capsule itself would have to move forward and back when you switch from hi-beam to lo-beam.

Again- think of the Maglite. Changing the relative position between the lamp and the reflector by just one or two mm changes the beam pattern dramatically.


Again, I think that this is only going to be approximated at best. Looking back at the image of the H4 lamp I posted earlier, the shade actually encompass the lo-beam filament. It wraps around it not only on the sides, but also the front and back. Given that the HID capsule assembly is enclosed inside a secondary, cylindrical glass envelope, there is just no way you are going to achieve that kind of coverage with a mechanical shade, especially given the need to articulate either the shade or the capsule depending on whether hi-beam or lo-beam operation is desired.



Not too hard? It's totally impossible given that you can't get behind the HID capsule owing to the cylindrical envelope which encloses it.


It's a function of both the reflector design and the spacial relationship between the reflector and the light source. The latter is going to be quite difficult to replicate under both hi-beam and lo-beam conditions. At best, you might be able to optimize the position of the capsule for lo-beam operation, however I'm not aware of any fore-aft adjustability which is inherent in the design of either an H4 reflector assembly or an H4-based HID assembly.


Here's a diagram of the '99-'03 RL headlight assembly (left side):

A couple of observations. First, this assembly uses separate lamps and separate reflectors for hi-beam and lo-beam operation, rather than combining both modes of operation into a single assembly as do our H4s.

I'm also not aware that this particular reflector assembly was used in any other Acurae which ran a halogen-only setup, so I'd imagine that the designers were able to optimize the design of the reflector for the position and characteristics of the specific light sources used.



Again, I'm not trying to argue here. Both you and Abe have done this and so it's obvious that it works. I merely hold that it is less optimal to stick an HID capsule into a reflector designed for a halogen lamp, particular in a twin-filament design, than to install one into a housing designed and intended for use with the HID lamp in the first place.

Dust

There are untold numbers of OEM reflector headlights with OEM HID bulbs. The upper level version of my car cam with them, and I have been looking for them

What I take from this thread

NA - SOL for now

NB - OEM projectors work fine with a proper HID kit, at least that is what I got from page 1

Doppelgänger

iTrader: (12)

I know the Acura RL, the Nissan Maxima and a couple others have HID in reflectors as OE, and those things still bother me, mostly the Acuras.

I was doing more research on all of this yesterday and came to a mildly surprising bit of information. It seems that halogen equipped projectors are actually different from HID equipped projectors and that the position of the light source and shape of the lens is different. So technically not all projectors are "made" for use use with HID. While it's still clearly a much better solution, I couldn't find a specific reason of "don't use HIDs in projector housings because x,y and z". All I could find was that there is a design difference between xenon projectors and halogen projector shapes.

Insert foot in mouth? Perhaps. I'd like to find a S2K or similar low car with OE HIDs and compare the light output/spread/pattern to my HID-equipped halpgen projectors. A E55/S2K/TSX projectore retrofit may be in order.

RotorNutFD3S

iTrader: (33)

I'm wondering how difficult it might be to crack open a set of those clear lights you see on eBay (that take H4 bulbs) and retrofit the projectors into those. There are sets on there as well that claim to be projectors simply because they have a projector lens built into them, but have no cutoff shield. Anyway, the result could be something that fits properly into the stock housing for those who don't like the low profile setups and it's waterproofed. The dimensions would make all the difference, but the projectors I used are not very large at all.

Cspence is running HIDs in the turn signal ports of his white car, no main headlights, but I can't recall if he's using a projector or not.

From what I've read HIDs in most halogen projectors will create some hot spots and minor light scatter, but nothing that you normally see unless you're really looking for it. The cutoff is usually still very sharp and the majority of the light goes where you want it to, like in your car or the Hella projectors in the Moss setup, which are halogen projectors. However some halogen projector housings simply cannot withstand the amount of heat HIDs create, you'll see either melted housings or the internal reflector material/coating bubble and flake off.

JasonC SBB

Dammit, I wrote that very badly.

What I meant was, a solenoid arrangement that properly moved the HID capsule such that the center of the HID light source in each of the low and high beam positions, is moved to the respective proper H4 low and high beam filament centers.

No Joe, re-write your above missive with my corrected statement in mind.

JasonC SBB

This may be because if an engineer were to do a clean-sheet design of the reflector or projector, one wouldn't restrict themselves to halogen-mimicking HID bulbs, but would consider all available HID bulbs and choose one for overall cost, reliability, performance, and manufacturability.

Perhaps the "halogen aping" HID bulbs were designed to either replace halogens in existing headlamp assemblies, OR were a means for their manufacturers to sell them to car manufacturers by overcoming the latter's resistance by requiring a *minimal* re-design of said existing assemblies. And perhaps later on, after HID's were accepted, said HID bulb designers then worked with headlamp designers to come up with a better system design which of course meant diverging from halogen-type designs.

This sort of thing happens all the time in the engineering world.

If indeed my theory is correct that the halogen reflectors in my miata and Focus were designed to have *some* scatter, it stands to reason that said scatter would be a little much with either a higher output halogen, or an HID bulb. Which as I observed looking at my own car, "is a bit annoyingly bright, but not too bad".

JasonC SBB

HIDs generate less heat than halogens.

Witness their power consumption: 35W for a typical HID, 55W for a typical halogen.

Joe Perez

iTrader: (8)

I've been wondering this myself. Power is power, and heat is heat...

Could it be that with a halogen, more of the heat generated is conductively coupled out of the assembly through the base, whereas with a xenon lamp, more of the heat is radiatively coupled into the surrounding plastics?

Or is this whole thing just a myth, and these housing would have melted with halogen lamps in them anyway?

I honestly have no idea.



Ok, now I understand why we seemed to be speaking at cross purposes. I didn't realize that you had found an H4-replacement HID in which the entire capsule moves forward and back- the few units I have personally seen had the capsule fixed in one location and moved a semi-cylindrical shutter back and forth around the capsule.

I still maintain that you're not going to achieve equivalent cutoff with a shade that is external to the outer envelope (on an HID assembly) vs. one which actually encompasses the light-emitting element (in the H4), however you're right in that the reflector performance show be comparable in a moving-capsule design, assuming that the movement of the capsule is properly calibrated to the nominal positions of the two elements in a halogen H4.

That would actually be a neat test for you to do: put your HID capsule side-by-side with a halogen H4, with the mounting surfaces aligned, and document the position of the HID capsule relative to the filaments in the H4 with the solenoid energized and de-energized.

Doppelgänger

iTrader: (12)

Understandable. Starting with a new type of lighting should have a fresh design to optomize it's capabilities.

As for light scatter being designed in, that is correct (as I noted earlier in post #14), to illuminate various overhead signage on the roadway. The question is, how much light scatter/percentage of lumens, is designed above the cutoff or outside the beam pattern on a reflector vs a projector. I knew we can't answer that here without the people who have designed them or a light meter. It is widely assumed that reflectors put more light out in this area compared to a projector and putting a HID in there increases the lumens outside the beam pattern enough to be seen as a problem to oncoming drivers. Oh trust me if I had the time/equipment I would love to know how much and what differences there are in both hosings with their native lighting and HID.

y8s

iTrader: (8)

could be that the HID is a more effective emitter of IR?

RotorNutFD3S

iTrader: (33)

It seems you might have hit it on the head. After reading some more into this, halogens radiate more infrared heat which is absorbed by all of the surrounding materials. HIDs radiate less infrared heat, however the heat they do produce seems to stay concentrated on parts in close proximity, which might explain why people are having problems with reflector coatings flaking off from inside the projector bowls (most coatings fail after 250º F) or housings melting.

I found a few different threads across the net with some readings taken on halogen and HID bulbs:

Halogen Filament Temp = 5,480º F
Halogen Bulb Glass = 1,100º F
Halogen Bulb Base = 415º F

HID Arc = 10,800º F
HID Bulb Glass = 1,385º F
HID Bulb Base = 465º F

Not concrete data since things can vary from bulb to bulb and applications, but HIDs definitely create more heat at their origin. How it's transmitted to the rest of the parts in housing seems to be completely different. I'd love to get ahold of the proper measuring equipment, I could put my car next to my g/f's '00 and do some direct comparisons.

JasonC SBB

Imagine placing said H4 on low beam in the center of a 1 ft diameter plastic translucent globe. You will see a shadow on the globe. Draw its outline with a sharpie. Your task is to design a shade for an HID capsule that sits outside of it, that produces the same shape shadow... I don't see why this would be too difficult.

JasonC SBB

<duplicate post>

JasonC SBB

Linky? Is this with the same power rating? Or 35W vs. 55W?

Heat is not the same as temperature BTW.

A lower power HID will definitely generate less heat than a halogen, but the way the heat gets out could indeed be very different.

The IR content may be it - perhaps most of the heat from the halogen gets out in the form of IR and reaches whatever is being illuminated (road, garage door, oncoming driver's retinas). If the light from a halogen on your thighs when standing in front of the headlamp feels hotter than from HIDs despite the dimmer output, then this statement is true.

And then the heat generated by the HID may be conducted back down to the base, resulting in higher temps at the base.

This thread *really* is turning interesting.

Joe Perez

iTrader: (8)

Yet it almost turned necrotic.


A bit of light reading has supplied some anecdotal descriptions of the physical architecture of HID assemblies in general. Wikipedia, for instance, has this to say:It seems probable that the outer glass envelope might, in addition to protecting the inner capsule from physical damage, might also serve to attenuate the high levels of UV radiation being emitted.

If this is the case, then it is plausible that HID assemblies of higher quality (and, one presumes, greater cost) might utilize outer envelopes which, due to differences in their composition or coating, are more effective at attenuating the UV radiation produced in the arc.

Now, unlike infrared light, UV does not typically have a pronounced heating effect. It does, however, cause the degradation of plastics and other polymer materials by fading and cracking. Think of a plastic toy which has been left outside in the sun for several months- it becomes discolored and brittle.

JasonC SBB

Hmmm I wonder if there are reports of factory headlamp plastic lenses turning brittle or yellow after a few months of HID usage.