# About fog lights...



## Wretchy (Aug 31, 2003)

Just need to know 2 things

1). Are the stock fog lights Xenon lights? 

and if not

2). Are there xenon fog lights available?



I just want my fog lights to look like my headlights.... I don't like the blue/yellow vibe I got going on


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## SONET (Mar 1, 2002)

The fogs are halogens, which are a yellowish white. Yellow actually works better for fog. What do you intend to use them for - when there's actually fog, or just to blind oncoming motorists on perfectly clear nights? :dunno:

--SONET


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## doeboy (Sep 20, 2002)

SONET said:


> The fogs are halogens, which are a yellowish white. Yellow actually works better for fog.


:eeps: :eeps: :eeps:


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## alee (Dec 19, 2001)

doeboy said:


> :eeps: :eeps: :eeps:


 :bigpimp:


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## doeboy (Sep 20, 2002)

alee said:


> :bigpimp:


:bustingup :bustingup :bustingup
:lmao: :lmao: :lmao:


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## alee (Dec 19, 2001)

doeboy said:


> :bustingup :bustingup :bustingup
> :lmao: :lmao: :lmao:


Get out of my way, all of you!

This is no place for loafers.

Join me or die.

Can you do any less?

:rofl: :rofl: :rofl:


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## The Roadstergal (Sep 7, 2002)

alee said:


> :bigpimp:


Asuma Light! :rofl:

Xenon fog lights! Cool! I want a Xenon night light at home, too!


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## andy_thomas (Oct 7, 2002)

Wretchy said:


> Just need to know 2 things
> 
> 1). Are the stock fog lights Xenon lights?
> 
> ...


Yes, Xenon foglights are available from some BMW dealers (mostly German ones). They also sell completely clear rear lamp clusters, so coming from a BMW dealer with a BMW badge on it is no indicator of quality, usefulness or fitness for purpose.

The reason your deeply upcool foglights aren't that funky blue is because yellow light is favourable in fog. By all means retofit HID units or "Toilet Duck blue" foglight bulbs, but please stop calling then "foglights" because they'll be utterly crap in fog, and you'll just blind yourself and others.


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## johnf (Sep 16, 2003)

andy_thomas said:


> The reason your deeply upcool foglights aren't that funky blue is
> because yellow light is favourable in fog.


In what sense? The absorption and scatter of blue light in fog is not appreciably greater than yellow. If it were, clouds (fog with some altitude) would appear colorfully psychedelic - without drugs.


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## doeboy (Sep 20, 2002)

johnf said:


> In what sense? The absorption and scatter of blue light in fog is not appreciably greater than yellow. If it were, clouds (fog with some altitude) would appear colorfully psychedelic - without drugs.


Light with higher color temp tends to reflect back to the driver in the water droplets in the air more... thus causing glare or the inability to see well....

lower color temp (like yellow) does not reflect off the water in the air as easily and thus causes less glare so to speak.

This issue has been discussed in quite some depth here before. Do a search and you'll find some good explanations on why this is so.


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## johnf (Sep 16, 2003)

doeboy said:


> Light with higher color temp tends to reflect back to
> the driver in the water droplets in the air more... thus causing glare
> or the inability to see well....
> 
> ...


I did two searches, one for

"color temp"​
the other for

yellow fog​
Plowing through the matches took about 30 minutes. I gather a fair number of people think yellow fog lights look cool. Can you point me to a specific thread? Thanks!


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## andy_thomas (Oct 7, 2002)

johnf said:


> In what sense? The absorption and scatter of blue light in fog is not appreciably greater than yellow. If it were, clouds (fog with some altitude) would appear colorfully psychedelic - without drugs.


Hi John .

AIUI blue - hotter - colour temp scatters more, so removing it (with a filter) purportedly reduces scatter. On this basis red is even better, but not used for obvious reasons. Filtering reduces output of course, so careful lens/reflector design is required.

I have tried yellow filters in front of regular foglights to see if they improve effectiveness, but they didn't make a big difference to visibility - probably because of the point above.

BMW's aftermarket HID foglamp kit appears to use the same housing as the regular halogen kind, which to me means it uses the same reflector. I'm no lighting expert but I would assume that different colour temp and intensity would require a different reflector design, so my money is on this being a "form" rather than "function" accessory. And the last thing we need is more foglamp abusers running more HIDs!

Another possible reason for the use of yellow foglights is that yellow light causes less eye fatigue. As driving is fog is never particularly pleasant, it stands to reason that you'd want to use a less stressful colour. It's also one reason (apart from lower cost) why most streetlights are yellow or amber, rather than white.


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## doeboy (Sep 20, 2002)

johnf said:


> I did two searches, one for
> 
> "color temp"​
> the other for
> ...


I believe threads that talked about this were discussing higher color temp HIDs also... but the idea is the same...

it seems most people think the "blue" lights look cool... those that want fogs that work better tend to change to yellow. I don't remember the specific thread... just that there were many discussions on fog lights and just lighting in general.... maybe a search for fog lights might get some hits too.


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## doeboy (Sep 20, 2002)

andy_thomas said:


> Another possible reason for the use of yellow foglights is that yellow light causes less eye fatigue. As driving is fog is never particularly pleasant, it stands to reason that you'd want to use a less stressful colour. It's also one reason (apart from lower cost) why most streetlights are yellow or amber, rather than white.


And probably why a lot of race cars like in Le Mans... run selective yellow headlights.....


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## elbert (Mar 28, 2002)

doeboy said:


> And probably why a lot of race cars like in Le Mans... run selective yellow headlights.....


I think the reasoning was to distinguish the faster cars from the slower ones. The LMP's and GTP's run white, while the GTS and GT classes use yellow. The yellows are still really bright though--they are basically xenon lamps with clear yellow tape on top.


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## doeboy (Sep 20, 2002)

elbert said:


> I think the reasoning was to distinguish the faster cars from the slower ones. The LMP's and GTP's run white, while the GTS and GT classes use yellow. The yellows are still really bright though--they are basically xenon lamps with clear yellow tape on top.


Hmm.. that's interesting... I'm not too familiar with how that series works. But for yellow lights... I believe France runs selective yellow headlamps in certain scenarios too...


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## Kaz (Dec 21, 2001)

elbert said:


> I think the reasoning was to distinguish the faster cars from the slower ones. The LMP's and GTP's run white, while the GTS and GT classes use yellow. The yellows are still really bright though--they are basically xenon lamps with clear yellow tape on top.


No, I believe it was originally because several years ago, French road regs stated that headlights MUST be yellow (no longer). Since the GT and GTS classes are 'road' cars, and because technically parts of the LeMans circuit is on public roads, maybe they needed to meet those requirements.

Japan also allowed yellow headlights for safety reasons (remember, this is the country that required fender mirrors for safety reasons into the 80s) for some time. I believe it is still allowed but cars are no longer sold with them.


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## elbert (Mar 28, 2002)

Kaz said:


> No, I believe it was originally because several years ago, French road regs stated that headlights MUST be yellow (no longer). Since the GT and GTS classes are 'road' cars, and because technically parts of the LeMans circuit is on public roads, maybe they needed to meet those requirements.


Possibly, but all cars were required to "trunk spaces" and all those other weird ACO rules, even the (now called) GTPs. My point is that those road-going car rules have been applied to all classes, not just GTS or GT.


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## missing23 (Feb 1, 2002)

Ahh, poor guy's 32nd post and scared away forever...

:rofl:


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## Matthew330Ci (Sep 9, 2002)

I bet all the kids driving Lexus IS300's are ashamed of their super-golden-yellow foglights.


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## doeboy (Sep 20, 2002)

Matthew330CiM said:


> I bet all the kids driving Lexus IS300's are ashamed of their super-golden-yellow foglights.


I'd take'em off their hands if the bulbs are HB4.... :eeps:


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## elbert (Mar 28, 2002)

doeboy said:


> I'd take'em off their hands if the bulbs are HB4.... :eeps:


I think the yellow comes from the lens (unfortunately).

The Phillips All Weather aren't that yellow. The closest I could come up with are some PIAA's from Japan, but at around $100 a pair...


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## elbert (Mar 28, 2002)

greginaz1 said:


> Ahh, poor guy's 32nd post and scared away forever...
> 
> :rofl:


Yeah, if he isn't scared away by now, then he's hopefully learned from this.


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## doeboy (Sep 20, 2002)

elbert said:


> I think the yellow comes from the lens (unfortunately).
> 
> The Phillips All Weather aren't that yellow. The closest I could come up with are some PIAA's from Japan, but at around $100 a pair...


Actually, I already got these:









Much cheaper... $60... and might even last longer... but too early to tell yet...

I'm just curious to compare the yellow they use with the Polargs... heh...


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## elbert (Mar 28, 2002)

doeboy said:


> Actually, I already got these:
> 
> 
> 
> ...


Sheesh, how did I miss this thread?
http://www.bimmerfest.com/forums/showthread.php?t=36019&highlight=polarg

Maybe trying to tint the lens is the next step if the polargs are disappointing, as Kaz seemed to indicate.


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## doeboy (Sep 20, 2002)

elbert said:


> Sheesh, how did I miss this thread?
> http://www.bimmerfest.com/forums/showthread.php?t=36019&highlight=polarg
> 
> Maybe trying to tint the lens is the next step if the polargs are disappointing, as Kaz seemed to indicate.


Well... actually I took them off his hands... they were underwhelming because he replaced his running lights with some kind of "hyper yellow" bulbs.... which makes the Polargs look weird when run next to the running lights...

Mine are still stock amber running lights... so the Polargs don't look weird.... they actually look okay...


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## LmtdSlip (May 28, 2003)

It annoys me to no end to see all the BMWs on the road with their fog lights on at all times. They run their parking lights with fog lights or run the fog lights on all the time when it is perfectly clear out.

It is VERY annoying and seems to be prevelant among E36 more so than E46.


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## johnf (Sep 16, 2003)

LmtdSlip said:


> It annoys me to no end to see all the BMWs on the road
> with their fog lights on at all times. They run their parking lights
> with fog lights or run the fog lights on all the time when it is
> perfectly clear out.


When I was car shopping a few years back I happen to ask the BMW CCA's
product specialist how often she used her foglights. She replied: "All
the time".  This confirmed how many U.S. BMW owners seem to treat
them, in my father's words, as "decorative, forward, auxiliary
lighting".



> It is VERY annoying and seems to be prevelant among E36 more
> so than E46.


Do you have to turn on the foglights with every start on the E46?
That might explain the difference.


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## foolio (Dec 24, 2001)

*Make them whatever color you want...*

According to this, it doesn't even matter. And, these guys had a relatively scientific approach to measuring this...

http://www.gi.alaska.edu/ScienceForum/ASF5/593.html


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## doeboy (Sep 20, 2002)

johnf said:


> Do you have to turn on the foglights with every start on the E46?
> That might explain the difference.


Yes you do.... which is why those with E46s that have fogs on in clear weather are usually considered irritating as they consciously turn the lights on...


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## johnf (Sep 16, 2003)

foolio said:


> According to this, it doesn't even matter. And, these
> guys had a relatively scientific approach to measuring this...
> 
> http://www.gi.alaska.edu/ScienceForum/ASF5/593.html


Too bad the author didn't list his 200 references, I would have liked
to check some of them!

There are a couple difficulties to the repeated claims that blue fog
lights produce more glare (more back scatter) than yellow (or red) and
that they penetrate less deeply (suffer more absorption). The first is
theoretical: the loss of visibility caused by fog is largely described
by wavelength-independent scattering within the geometric optics
regime. The second is observational: if the claims were true, your
headlights shining at the fog would give it a blue tint and the
headlights of oncoming cars shining through the fog would look and
make it look reddish.

There may be advantages to having yellow fog lights, but less back
scatter and greater penetration are most likely not among them!


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## LmtdSlip (May 28, 2003)

doeboy said:


> Yes you do.... which is why those with E46s that have fogs on in clear weather are usually considered irritating as they consciously turn the lights on...


Same with the E36. There is a seperate button for the fogs. Fogs can only be turned on once, at least, the parking lights are turned on. Thus the idiots that run their parking lights and fogs as an alternative to the headlamps. :tsk:

They also automatically turn off when you activate the high beams and turn back on when you dim the high beams.


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## doeboy (Sep 20, 2002)

LmtdSlip said:


> They also automatically turn off when you activate the high beams and turn back on when you dim the high beams.


Yup... mine does that too if I flash the highs... I don't think I've tested that with the bi-xenon high though... I'll have to test that in my garage one day...


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## johnf (Sep 16, 2003)

LmtdSlip said:


> The [fogs] also automatically turn off when you activate the high beams and turn back on when you dim the high beams.


That strange behavoir may only be true in the U.S. In Germany, I think they have to stay on: at least that is one way I can read the StVO.


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## Desertnate (Mar 11, 2002)

LmtdSlip said:


> They also automatically turn off when you activate the high beams and turn back on when you dim the high beams.


Mine don't... :angel: I believe this was an error in the ECU programming when the dealer swapped my settings from US to Euro on the lights (i.e. the amber corners work only as blinkers and not running lights/blinkers as well as the "city lights")

It comes in real handy on the dark country roads I would commute. I could through off some serious light using every lamp on the front of the car! The fogs would light up the shoulder where the critters used to wait in order to throw themselves under the wheels of my car.

No...I don't drive around with the fogs on unless the above situation or fog.


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## foolio (Dec 24, 2001)

Desertnate said:


> Mine don't... :angel: I believe this was an error in the ECU programming when the dealer swapped my settings from US to Euro on the lights (i.e. the amber corners work only as blinkers and not running lights/blinkers as well as the "city lights")
> 
> It comes in real handy on the dark country roads I would commute. I could through off some serious light using every lamp on the front of the car! The fogs would light up the shoulder where the critters used to wait in order to throw themselves under the wheels of my car.
> 
> No...I don't drive around with the fogs on unless the above situation or fog.


I find fogs useful when it is raining at night. Roads that have old markings don't reflect light as well when they are wet and the fogs seem to make the lines show up better. Other than that, my fogs are off 99.9% of the time.


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## johnf (Sep 16, 2003)

foolio said:


> I find fogs useful when it is raining at night. Roads that have old markings don't reflect light as well when they are wet and the fogs seem to make the lines show up better.


A similar situation when fogs are handy is when you are driving an
unlit, snow covered highway at night. The extra light up close makes
it easy to stay in the track and lets you concentrate on what is
further ahead.

Plenty of people will tell you that the extra near field light will
distract you. Try it and I think you will find this has things exactly
backward. I think _a lack_ of light can distract you, but then again,
I don't understand yellow fog lights.


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