Some more thoughts on headlights

[BennyM]

There's been a lot of talk lately about headlight modifications and so I wanted to share some thoughts with you guys. I work with lighting and lenses a lot, but I am by no means an engineer, so feel free to prove me wrong.

Our cars were designed to run with 9006 bulbs for a reason. I suspect the opaque tip serves some specific and crucial function for directing the light rays to where they are supposed to go (the road) and away from where they aren't supposed to go (people's eyes).
I made this crude diagram to illustrate my hunch.
http://i63.photobucket.com/albums/h132/bennyboym/Picture1-4.png
This is based on my observations of how the light shoots out of the projector lens on our cars. (For those of you with out projectors, this doesn't really apply.) So if the tip is removed, I wonder if more of that light gets directed toward the wrong places. I probably have the reflector shape wrong and there may be another lens that I haven't accounted for, but I think the question is still valid. So, please, let me know your thoughts. All in all, I still plan to upgrade to HID as soon as I get the extra cash.

BennyM

[BMWCCA1]

Well, for one, you don't show any influence of the ellipsoid lens on the light pattern. Your diagram implies the reflector is solely responsible for the direction of light. In other words, you've accounted for reflection but not refraction.

[BMW4LIFE]

Well, for one, you don't show any influence of the ellipsoid lens on the light pattern. Your diagram implies the reflector is solely responsible for the direction of light. In other words, you've accounted for reflection but not refraction.

yea what he said..... ;):D

[BennyM]

What is it that creates the cutoff at the top of the light pattern? Is it the reflector combined with the painted tip or is it the lens(es)? Does anyone have a picture of the light pattern after a 9005 conversion?

BennyM


Well, for one, you don't show any influence of the ellipsoid lens on the light pattern. Your diagram implies the reflector is solely responsible for the direction of light. In other words, you've accounted for reflection but not refraction.

[Paul in NZ]

the cut off is not dependent on the bulb...euro cars have H1 bulbs,which dont have a painted tip....I dont see the point of your post Benny...at first i thought you were going to say our cars shouldnt have hids....but then you say you are going to get them anyway?

[uscharalph]

One of my pet peeves: Poorly directed headlights.

[winfred]

i don't think all that much light comes from the tip of the bulb as that is the small end of the filiment, and what does make it through gets handled by a decent lens, i think the painted tip if more for the shitty plastic 90s lights with pretty much no containment, like my truck, the lights on it blow ass

[RallyD]

the ellipsoid cutoff is done with a piece of metal just behind the projector lens. i'll try and get a pic of one that I have disassembled at home.

[Russell]

the ellipsoid cutoff is done with a piece of metal just behind the projector lens. i'll try and get a pic of one that I have disassembled at home.

Exactly. The black tip does not impact the light pattern much, if at all. I noticed this when I did the 9005 bulb conversion. BTW, HIDs work great with ellipsoids (duh). One of the best mods I have done.

[BMWCCA1]

What is it that creates the cutoff at the top of the light pattern? Is it the reflector combined with the painted tip or is it the lens(es)?It's the outer lamp lens, at least with our lights. That's why RHD cars traveling in Europe use a stick-on mask to kill the glare to oncoming drivers. There's also a metal "shield" as part of the ellipsoid lens holder that some people modify to improve the light pattern, as mentioned above. The reflector is pretty much parabolic and symmetrical.

[BennyM]

I do plan on getting the HIDs, but I wanted to hear what you guys had to say about the intent of the original design and whether or not we might be negating some important safety feature first. I wanted to be doubly sure. Fortunately, it doesn't sound like the bulb converters are doing any harm.

I still don't understand why BMW wouldn't use H1s or 9005s for the projectors and 9006s for the open face fixtures. There must have been a reason......
Regardless, you guys have certainly eased my doubts.

Thanks.

BennyM


the cut off is not dependent on the bulb...euro cars have H1 bulbs,which dont have a painted tip....I dont see the point of your post Benny...at first i thought you were going to say our cars shouldnt have hids....but then you say you are going to get them anyway?

[leicesterboy15]

I still don't understand why BMW wouldn't use H1s or 9005s for the projectors and 9006s for the open face fixtures. There must have been a reason......
Regardless, you guys have certainly eased my doubts.

Thanks.

BennyM

In the UK they use H1s with projectors. Anyhoo I've taken the plunge and converted to HiD and they are superb. I looked at the kits available and they all looked uncannily similar and were very similar to the stock HiD kits from the factory so I figured the difference in quality is probably minimal so I did the right thing and went for the cheapest i could possibly find. They turned out to be superb! Easy to fit, look factory, look good when on, no errors from the computer, 100% reliable (so far) and I can even see at night which was a challenge before. Check 'em out, guy ships all over the world:

http://cgi.ebay.co.uk/HID-XENON-CONVERSION-KIT-H11-H7-H4-H3-H1-9005-9006-9007_W0QQitemZ300278488647QQcmdZViewItemQQptZUK_Ca rsParts_Vehicles_CarParts_SM?hash=item300278488647&_trksid=p3286.c0.m14&_trkparms=72%3A1301|66%3A2|65%3A12|39%3A1|240%3A13 18

[attack eagle]

I still don't understand why BMW wouldn't use H1s or 9005s for the projectors and 9006s for the open face fixtures. There must have been a reason......


there is---
they are illegal to use in lowbeams in the US because they are 55w bulbs.

that is the only reason at all.


Lowbeams are limited to 35 watts by law in the US (which is also why factory HIDs like DS2 are 35w units)

[winfred]

huh? theres a **** load of 55w low beams the H7 for instance, goes in most modern cars


there is---
they are illegal to use in lowbeams in the US because they are 55w bulbs.

that is the only reason at all.


Lowbeams are limited to 35 watts by law in the US (which is also why factory HIDs like DS2 are 35w units)

[bubba966]

There's no difference in the cutoff between the 9006 and a 9011 HIR (HIR version of a 9005) in my car. So as has been mentioned I don't see the tip of a 9006 doing much if anything to effect the pattern in our cars.

[Claude]

What is it that creates the cutoff at the top of the light pattern? Is it the reflector combined with the painted tip or is it the lens(es)? Does anyone have a picture of the light pattern after a 9005 conversion?

BennyM

Have a look to that reference, you'll found picture and explanations: http://en.wikipedia.org/wiki/Headlamp

[BennyM]

Thanks! Very informative. I should have checked wiki first.

[attack eagle]

huh? theres a **** load of 55w low beams the H7 for instance, goes in most modern cars

You are correct, should have said are limited to 55w.
9005s are 65w bulbs.
H1s were illegal for use in headlights seeking DOT approval until the mid to late 90s. there was a short list of approved bulbs, and they all started with 900_ until then.