HID conversion for fog lights

[outahere]

..........As for the color selection… yeah, we done some studies with that as well. Contrary to popular belief, a 4300°K bulb is still a better choice in inclement weather verse the more “yellow” 3000°K bulb. ..........

 

Has Hella published these findings anywhere? I would like to read more about this.

[SuperhawkLGT]

[TSiWRX]

Has Hella published these findings anywhere? I would like to read more about this.

 

+1. I'd like more info. on this, too.

 

The RPI papers that brother outahere was so kind as to point me to definitely seemed to point to those results, too, and I'd like to know if my eye/brain is indeed fooling itself into thinking that the "selective yellow" is better - or if I really should switch back to whiter lighting, even for this application.

 

[Bbc84]

I got 3000k HID fogs and 6000k low beams on my 08 LGT, the fogs are still kinda useless but they do help in wet weather, they seem to give a contrast between the 6000k low beams and also seem to blend with them making it more white output on the road it seems.

[TSiWRX]

^ This, I think, may be an area that can only be addressed with revised optics for the fogs. Although I like mine just fine, particularly after just a little re-aiming, I still think that they are far from being what I've had slaved onto my various DSMs in the past -> and that includes some generic fogs that were purchased from nothing more than the local auto-parts store.

 

Output isn't everything.

[outahere]

Here is a link to a paper from the Univ of Michigan Transportation Research Institute, where you can download a pdf.

 

Their surprising conclusion: front fog lamps have no demonstrable safety benefits, and rear fog lamps are more effective at reducing collisions.

 

http://hdl.handle.net/2027.42/49453

[NSFW]

That should be required reading for anyone taking part in any argument about fog lights.

[Guest]

Here is a link to a paper from the Univ of Michigan Transportation Research Institute, where you can download a pdf.

 

Their surprising conclusion: front fog lamps have no demonstrable safety benefits, and rear fog lamps are more effective at reducing collisions.

 

http://hdl.handle.net/2027.42/49453

 

Agreed. That's why I have rear fog on my wagon.

[TSiWRX]

 

http://hdl.handle.net/2027.42/49453

 

I'm getting a server error when I try to connect. NSFW, did that link work out for you (-> is my trouble temporary)?

 

I'm getting this error:

 

Error - Cannot Connect to Server

 

The handle you requested --

2027.42/49453

-- cannot be found.

 

 

I'll definitely agree that having a rear fog is a huge advantage. I keep thinking about retrofitting one to the sedan. There's a local who retrofits to WRXs, and although I've only seen the application on European-origin vehicles, I can definitely "see" the safety advantage.

[outahere]

I'm getting a server error when I try to connect.........

 

there seems to be a problem at the Univ of Michigan. I tried connecting to their online library, and got an error message.

[TSiWRX]

^ Thanks for checking for me. I'm a "B-" when it comes to computer literacy, and I just wanted to be sure that it isn't something on my side that was causing the problem.

[TSiWRX]

Finally got the article - great read!

 

OK, so lets see if I've got everything right ( all stated in lay terms ) ->

 

(1) true fog lights do *not* increase overall forward vision, particularly at-distance, under any conditions; low/high-beams actually offer greater advantage for distance vision under foggy conditions, with use of the latter only being not recommended under dense fog conditions

 

- the first part of this, I think, is relatively commonly known even among us laymen, however, the second conclusion is definitely one that I did not know, and is, what's more, against conventional "road wisdom" as it's been taught to us over the ages; I'll definitely keep that in mind the next time I encounter foggy situations, and alter my lighting scheme per the recommendations of this excellent review article

 

(2) advantage of fog lights is to increase peripheral/guidance vision at extreme short ranges only

 

- again, not surprising, and is in-accord with general knowledge at this point

 

(3) enhanced guidance can be a false-comfort, since focal vision - necessary for, for example, avoiding an unexpected intrusion into the roadway at-distance - is compromised with typical lighting schemes that increase foreground vision (spatial guidance/lane maintenance) - but how this may factor into fog/degraded-weather performance is still yet unknown; proposed mechanism of give-and-take benefits/risks poses a situation where insufficient forward lighting under such adverse weather conditions is paired to an increase in guidance, causing just such a false-security scenario

 

- now this one is very interesting...I've never thought of it this way - I've always thought of potential side-benefits from having good foreground illumination, particularly in areas where ambient lighting makes it difficult for drivers with specific visual needs to clearly see roadway delineations and/or curbs, but this "reverse" argument certainly does make sense logically, and the data seems irrefutable; I've always taught the wifey to drop her fogs when she goes out further into the suburbs, where the increased vehicle speed as well as the need to have farther-away vision is more important, but now I can't help but wonder if this kind of statistic holds true for in-city situations as well

 

(4) since, statistically, the biggest traffic safety hazard under foggy conditions is rear-on collisions, caused by an inability of the following vehicles to properly visualize those in-front; rear fog lamp(s) should significantly address this concern

 

- this article just may have given me the kick that was due to rig a rear fog to both of our vehicles

 

Great review article. Thanks again, outahere!

 

Also, if I'm reading this right, there may be some good benefits to be had by re-wiring our headlights to offer simultaneous high, low, *and* fog-light illumination, for most fog scenarios, correct?

[outahere]

TSi+WRX, that's a good summary.

 

Below are some of my impressions after reading several of these papers.

 

1.Fog lamp location, and beam geometry, are more important than light color. For example, contrary to popular wisdom, fog lamps perform better when mounted higher, at 24" instead of 14".

 

Quoted from the paper; "Yokoi and Hashimoto also investigated the same fog lamps mounted at 600 mm. The fog lamps performed better when they were mounted higher, but comparisons to the low beams were similar. At all distances at which visibility thresholds could be measured, the low beams offered better visibility (corresponding to denser fog, quantified by shorter visible range) than fog lamps. "

 

2.Yellow light offers a small vision advantage in fog, compared to white, but this advantage is negated by the reduced lumen output of yellow bulbs.

 

3.Best performance in fog and falling snow would be achieved by asymmetric lighting, greatly dimming the lights on the drivers side, and leaving the passenger side lights at full power.

 

4. The current SAE standards for fog lamps are woefully outdated and inadequate.

[fishbone]

Just get these

http://store.candlepower.com/tugoseyeh355.html

or these if you want light and not yellow

http://store.candlepower.com/naraulhiou551.html

for your fogs and call it a day.

I have the GE Tungsram and if you want a comparo, they're like the yellow fogs on a Lexus IS300, but look better with our housing

You can see my comparo pics here:

http://legacygt.com/forums/showpost.php?p=1462443&postcount=161

Keep in mind they're not THAT yellow, it's a trick played by the camera, but the yellow is definitely there.

 

Also, at least according to Daniel Stern, OSRAM +65 Rallye put out more lumens than the Philips Xtremes. 2100 lumens vs 1620 lumens. They also don't last as long. 500 hours vs 200 for the Philips bulbs.

[outahere]

Fishbone, I did install the Narva RangePower+50 H3 bulbs in the OEM fog lamps, and noticed no improvement. And I adjusted their aim.

 

IMO, the OEM projector fog lamps are a very poor design. They seem to waste, or block, a lot of the available light from the bulb.

 

OTOH, the OEM low beam projectors seem to be of better than average design and output. Go figure! I bet the fogs are an inexpensive, "off the shelf" item, while the headlamps are custom designed.

[fishbone]

I will never understand why one would attempt to get driving light out of the foglights when they were clearly not designed with such functionality in mind. For that kind of a role they have a poor positioning, shape, aim, etc. I don't mean to revive a conversation 7 pages old and long, but, IMO, stick to the fogs for what they were designed for: driving in bad conditions. And as far as that's concerned, what you want isn't more light, but more contrast. Precicely the reason you should go with something yellow, not brighter per se. Now, if you want more driving light, either go retro HID or add on extra reflectors/projectors. You have to pay to play, as they say.

[TSiWRX]

Hey bro,

 

1.Fog lamp location, and beam geometry, are more important than light color. For example, contrary to popular wisdom, fog lamps perform better when mounted higher, at 24" instead of 14".

 

*VERY* good catch.

 

Your later quote of the two authors' findings at 600 mm (this number got stuck in my mind today, as I was doing a lot of number-crunching with my own data-sets ) was able to remind me of this important factor, which I somehow totally forgot about!

 

Hum.....maybe I should rip the old Catz XLDs off the Talon, and put them up in the grill area of the Legacy? That would kill two birds with one stone - get the fogs up higher, and also allow for coplanar alignment of the driving lamps.

 

I'm still somewhat worried about heat, though.

 

2.Yellow light offers a small vision advantage in fog, compared to white, but this advantage is negated by the reduced lumen output of yellow bulbs.

 

I think that this was something that Stern and others have mentioned - regardless, it's good to bring this up again, though - per brother fishbone's discussion later on ->

 

3.Best performance in fog and falling snow would be achieved by asymmetric lighting, greatly dimming the lights on the drivers side, and leaving the passenger side lights at full power.

 

I *totally* missed this. I'll have to give those papers another read, and yes, I'll also confess to having not yet finished my homework, yet (read: I have yet to read all the papers). Most interesting concept, and I wonder how effectively we as individuals could implement this.

 

IMO, the OEM projector fog lamps are a very poor design. They seem to waste, or block, a lot of the available light from the bulb.

 

OTOH, the OEM low beam projectors seem to be of better than average design and output. Go figure! I bet the fogs are an inexpensive, "off the shelf" item, while the headlamps are custom designed.

 

Agreed - if only on a totally subjective basis, and without any possibility of confirmation, I still find myself hard-pressed to think any other way.

 

I think that for fogs, they do work as-intended, but they definitely do not work nearly as well as our wonderful OEM low-beams. Maybe the engineers just decided to slack, or maybe it was a budgetary/R&D funds issue?

 

I will never understand why one would attempt to get driving light out of the foglights when they were clearly not designed with such functionality in mind. For that kind of a role they have a poor positioning, shape, aim, etc. I don't mean to revive a conversation 7 pages old and long, but, IMO, stick to the fogs for what they were designed for: driving in bad conditions.

 

Totally agreed.

 

However, I am of the firm belief that it's as much a styling statement now as it is a problem of improper common usage/perception that's causing these lights to be used as-such. These papers specifically mentioned this issue, and I believe that they've hit the target right-on.

 

And as far as that's concerned, what you want isn't more light, but more contrast. Precicely the reason you should go with something yellow, not brighter per se.

 

That's what I'd thought, too - that the sacrifice in-trade of absolute range/brightness would be a good one. However, it seems that there is hard data (i.e. outahere's recapture point 2) to prove otherwise, even though the data was, as-cited by those authors, admittedly marginal.

 

With the data at-hand, I think that these authors would agree that this compromise could go either way, and let things be chalked-up to end-driver preference.

 

In this vein, I have to confess that I will now have to give white/clear-colored fogs another try. Just to be sure that my eye-brain isn't tricking me to think that something is better, based on previous conventional wisdom.

[outahere]

More grist for the mill.

In Stern's discussion of yellow bulbs, he refers the reader to the Bullough and Rea paper, published by SAE.

 

From their paper:

 

"For example, the effect of SPD when compared to other

headlamp factors, such as mounting position and beam

width[1,7,8,12,34-36], can be quite small. However, headlamp

SPD could provide additional degrees of freedom to the

automotive designer who does not have the flexibility to

choose an unlimited array of mounting positions or beam

angles." (SPD= spectral power distribution= color)

 

"It is possible to design a yellow or amber filter for a

halogen headlamp that results in a higher transmittance

and a lower s/p ratio than those used on existing

products. Such a lamp-filter combination would need to

have a low s/p ratio and relatively high photopic

transmission to provide measurable performance

benefits." ("A lamp's s/p ratio is the ratio of the scotopic and the photopic weighting of its SPD. A "blue" lamp will typically have a high s/p ratio and a "red" lamp will have a low s/p ratio.")

 

"While MH [i.e HID] lamps alone do not seem to offer advantages over

conventional headlamps with respect to their s/p ratio,

their higher light output relative to halogen lamps means

that such headlamps could perhaps be used with

colored filters, providing low s/p ratios that would be less

visually distracting than that from a halogen lamp while

still having greater light output."

 

I interpret this as meaning that if yellow bulb color is to have a significant effect when driving in snow or fog, light output will need to be increased over what a halogen bulb typically offers. And that means HID lighting, with the appropriate SPD and s/p ratio.

 

Based on the above paper, and others I have linked here, this is the way I see it: With halogen bulbs, if you want comfort in the fog, use a yellow bulb. If you want to maximize detection of distant objects in the fog (e.g. a stalled car in your lane) use a clear bulb. If you want comfort and distance detection, use a high output HID fog lamp with a yellow filter. That's my 2 cents.

[outahere]

........... Also, if I'm reading this right, there may be some good benefits to be had by re-wiring our headlights to offer simultaneous high, low, *and* fog-light illumination, for most fog scenarios, correct?

 

Only if you wear sunglasses at the same time. I think the glare might be overpowering. That level of light intensity might be doable with yellow light, given that humans can tolerate about 25% more yellow light than white light, before glare becomes uncomfortable.

[outahere]

.......Hum.....maybe I should rip the old Catz XLDs off the Talon, and put them up in the grill area of the Legacy? That would kill two birds with one stone - get the fogs up higher, and also allow for coplanar alignment of the driving lamps.

 

I'm still somewhat worried about heat, though. ..........

 

Are the XLDs one of those "2 lamps in 1"?

[outahere]

.......I *totally* missed this. I'll have to give those papers another read, and yes, I'll also confess to having not yet finished my homework, yet (read: I have yet to read all the papers). Most interesting concept, and I wonder how effectively we as individuals could implement this. ...........

 

The discussion about asymmetric lighting was in one of the papers about snowplow lighting. Pretty easy to implement on a snowplow, but a whole other ball game on a car.

[TSiWRX]

I interpret this as meaning that if yellow bulb color is to have a significant effect when driving in snow or fog, light output will need to be increased over what a halogen bulb typically offers. And that means HID lighting, with the appropriate SPD and s/p ratio.

 

Based on the above paper, and others I have linked here, this is the way I see it: With halogen bulbs, if you want comfort in the fog, use a yellow bulb. If you want to maximize detection of distant objects in the fog (e.g. a stalled car in your lane) use a clear bulb. If you want comfort and distance detection, use a high output HID fog lamp with a yellow filter. That's my 2 cents.

 

^ That seems a reasonable interpretation.

 

I guess getting the right SPD and s/p ratio - or "color," for laymen like me - would be the trick, then.

 

---

 

RE: The all-lights-on scenario ->

 

Only if you wear sunglasses at the same time. I think the glare might be overpowering. That level of light intensity might be doable with yellow light, given that humans can tolerate about 25% more yellow light than white light, before glare becomes uncomfortable.

 

That's a good point. I'd get oncoming vehicles to see me, but the glare from the highs would likely drown-out my own most-necessary and all-crucial forward visibility.

 

I guess this would be a case of "slow to where it's safe for our headlights (low + fogs), and pray that someone doesn't come flying up our tail" being the best and most-safe choice.

 

That rear fog is really calling out to me.....

 

Speaking of which:

 

Doing the rear-fog retrofit on the wifey's '05 WRX would be rather easy. But with the LGT sedan, I know I'll need to do some butchering/hacking of the rear housing.

 

What's your (and everyone else's, too) thoughts on the PIAA Deno-3 (ten red LEDs in their own housing) Rear Fog Lamp?

 

Where would I mount this piece?

 

I'd likely catch some flack from the police if I mounted it in my rear greenhouse, so that's out.

 

Would it be reasonable to mount this just under our rear bumper? or would that be way too low?

 

---

 

Are the XLDs one of those "2 lamps in 1"?

 

Yes and no - they're separate housings, but are otherwise integrated. The switchgear limits use of only one or the other lamp, and without opening the switch, I don't know if there's an easy way around this or not.

 

http://www.autodesignhaus.com/tuners/catz/images/xld-1.jpg

 

This is what I have on my current DSM - "gold" fogs (90-degree spread - IMHO, not quite wide enough) and clear driving (75-degree, good comfort for my eyes, but it noticeably lacks range/straight-line penetration).

 

The benefit of this now defunct piece would be that it's small enough to allow for in-grill mounting on our LGTs, versus, say, the PIAA 940 or P-4000 (using the "auxiliary low-beams," in this case, as fogs; the P-3000 I threw away in this consideration as it doesn't offer a true fog pattern). My issues, at the time-of-purchase of the XLD, were also partially space-related, as the DSM rides with a FMIC.

 

Your thoughts on this one?

 

---

 

The discussion about asymmetric lighting was in one of the papers about snowplow lighting. Pretty easy to implement on a snowplow, but a whole other ball game on a car.

 

^ Ah, that would explain why I hadn't read it, yet. I had back-burner'ed that one because of its unique application.

 

Still, that's no excuse for me - and I missed something rather important!

[outahere]

....That rear fog is really calling out to me.....

 

Speaking of which:

 

Doing the rear-fog retrofit on the wifey's '05 WRX would be rather easy. But with the LGT sedan, I know I'll need to do some butchering/hacking of the rear housing...................

 

I would be tempted to make the OEM high mount center brake light serve double duty as a rear fog lamp. But it might attract attention from the police. As to where to mount a separate rear fog, I say higher is better, and that means cutting a hole in your trunk lid. Bravery will be required.

 

I have no knowledge about the PIAA LED rear fog lamp. On a side note, an interesting shortcoming of LED automotive brake lamps is that they do not run hot enough to melt any snow and ice that accumulates on them.

[SuperhawkLGT]

You could mount the led rear fog lamp next to the license plate on the drivers side, plenty of room there, I was actually considering this some time ago.

http://www.shopatron.com/product/product_id=PIA19155/353.0

http://www.shopatron.com/product/product_id=PIA19153/353.0

[outahere]

.........This is what I have on my current DSM - "gold" fogs (90-degree spread - IMHO, not quite wide enough) and clear driving (75-degree, good comfort for my eyes, but it noticeably lacks range/straight-line penetration).

 

The benefit of this now defunct piece would be that it's small enough to allow for in-grill mounting on our LGTs, versus, say, the PIAA 940 or P-4000 (using the "auxiliary low-beams," in this case, as fogs; the P-3000 I threw away in this consideration as it doesn't offer a true fog pattern). My issues, at the time-of-purchase of the XLD, were also partially space-related, as the DSM rides with a FMIC.

 

Your thoughts on this one?

 

I think high mounting is a good idea, from an optics perspective. The one possible downside is that mounting these 4 lamps behind the grille will substantially reduce the grille opening, and could lead to engine overheating on hot days. Are you equipped to do logging of intake air and coolant temperatures, before and after install of these lamps?