Hello, I'm new to the forum and was hoping to learn a few things I couldn't find by searching
So I've been reading anything and everything I find on the topic of headlights, but a few things are still not clear to me. I haven't gone to the point of subscribing to access research papers or buying textbooks, but I'm getting close. Hopefully posting a list of questions gets at least a few answered and my post isn't deleted...
Small bit of background:
My questions:
This turned out incredibly long. Sorry about that. I could break it up if needed, or pare it down if needed.
Thanks. Hope I get to learn something and make good decisions once I get my hands on some upgrades.
So I've been reading anything and everything I find on the topic of headlights, but a few things are still not clear to me. I haven't gone to the point of subscribing to access research papers or buying textbooks, but I'm getting close. Hopefully posting a list of questions gets at least a few answered and my post isn't deleted...
Small bit of background:
- Currently shopping for an MR2 spyder
- Hoping to get as much front lighting as I can because I like going on backroad spirited drives at night
- Also hoping to improve headlights on our '06 Impreza due to its age
My questions:
- I'll likely be putting in relay harnesses in both cars at some point with the help of my electrical engineer friend. I have a few questions on what to expect.
- What's the best way to find out voltage drop at the headlights on my car? It appears to be lower than it should be, and I'm wondering if I should have it checked out before I put in a relay harness. The reasons I think it's lower is because the light output is quite weak and yellower than other halogen lights, frequently dims with almost any load, possibly after the voltage regulator died and I drove a few miles to get home while charging at 14-16V (which blew out a bulb and delivered the brightest halogen light I've ever seen out of the remaining headlight), and because there has been a rodent nest under the hood (cleaned out now)
- In a car with older or weak wiring, is there any danger in putting in low gauge wiring for the headlights? As far as I understand it replaces the whole high current headlight circuit from battery to ground, except to use the stock wiring from the switch to activate the relay.
- How much should I expect decent diy harness parts to cost for the impreza - 2x H7 lows, 2x 9005 highs?
- How does a relay harness work in a mid engined car (battery in rear bay)? I've heard that it has some kind of terminals up front, but I don't know if it already has relays for the lights, nor what gauge wiring it uses for the headlights and for the run from the battery to the front terminals. Should I wait and see if the wiring is sufficient?
- I can post a link if anyone wants to take a look at the 2000 MR2 Spyder wiring diagram for the headlights, although I'm shopping for the updated 2003+ which has H7 lows and 9005 highs, as well as fog lights. Might have to buy the service manual or a subscription to the online version and download as much as I can...
- Interested in restoring the Impreza headlights because the car isn't worth much and I won't be keeping it long enough to make new assemblies worth it
- I have a polishing kit, and have done it before, but since I used the included headlight "sealant", it's oxidizing again after a year.
- I've read about the methods, and was hoping for some up to date opinions
- There's the easy to apply Opti-lens that seems to have good results, requires no special curing lamp or spraying, and has a long shelf life. Only cons are that it's said to apply quite thin and it's expensive.
- I've read the spar varnish method, and the consensus later in that thread is that while it works, the clarity and durability aren't worthwhile, and it requires resealing once a year or two
- Then there's the GClear method. I remember coming across some similar alternatives, but didn't save them. This seems like one of the best options and a "lifetime" thing. Actually ends up being cheaper than the Opti-lens, but if there are cheaper versions of this, I'm listening. At 50$ it's still a great deal if it's a similar coating to the OEM UV coat. Only concern the the cost of the UV curing light. I can't find what kind of UV spectrum is needed, but polymerization in general seems to usually require a wavelength in the UVA spectrum. Would sunlight work? Otherwise, would a 365nm LED flashlight or curing lamp work or would I need a full UV spectrum high power light?
- Last option is a two part clear coat, but I'm no professional, and don't know if I could apply it smoothly. Is there a way to do this well or a guide for doing this properly? Also, I'm assuming by the MSDS that I'll need a full respirator, gloves, and goggles? Any info on what I should look for? Seems like a long term solution if done right, but the toxicity and my lack of spray painting experience is concerning.
- I have a pretty good idea of what bulb upgrades to get, but I wanted to confirm a few things.
- For the H7 low beams (on either car), I'm considering either the H7 Rallye or potentially the Philips XtremeVision or Racingvision.
- I know that the flux of the rallye is significantly higher, yet it has longer life, but I'm curious if it has the same filament luminosity. If it puts out more light but at a warmer (~100-200K) temperature, I would assume that's because it uses a larger, slightly cooler filament, right? Does that mean while overall output would go up, intensity around the center regions would not increase as much, or possibly be lower than the +XXX% bulbs?
- I've seen a decent test (by ALR on Facebook - they take multiple lux measurements based on peak reading and a few points specified by FMVSS) that showed that an H9 bulb in two different H11 projectors exceeded glare measurements just above and to the right of center. Should I expect the H7 Rallye to do the same or is the H9 bulb more similar to an H7 than an H11 in terms of filament position and size?
- Any opinions on the best 9011 bulb? I saw a comparison on HIDPlanet (I know, I know) that showed that a new Osram/Sylvania made in Korea HIR1 put out more output, and significantly more intensity than the other bulbs. It seems it also has a smaller, tighter filament, based on the close-ups of the bulbs. I can edit in a link if anyone wants to see that comparison.
- I've read the few threads talking about auxiliary low beams, and none of them seem to be conclusively for it against them, so I'm still curious. I know I should wait and see if the upgraded lighting is sufficient, but we're not on this forum because we're happy with sufficient, right?
- I was thinking about adding the Hella premium 90mm H9 bi-halogen lights into the similarly sized fog light mounts. I'm assuming this would be below the legal mounting points for low beams, even auxiliary ones?
- From what little testing I've seen done on this, it does appear that the SAE version is a very good, high intensity light. User Hilldweller, on a Jeep forum, recommended them as the best halogen upgrade available for the 7" round housings.
- The testing also seems to suggest that their beam profile is balanced towards the top of the beam. As in they put most of the intensity above the 1-2 degree mark, which, from what I remember about trigonometry, should put the light out between 40 and 180 feet, when mounted at what I estimated the height of the fog light housings. Would this still overlight the foreground?
- So this is out of curiosity, not because I would do so, but given a low enough mounting height, wouldn't lights aimed level or just slightly up theoretically not cause glare? Even if they were aimed VOR at say .2 up, they wouldn't reach driver eye height for well over 100m, at which point they wouldn't produce more than 1lux anywhere in the beam? According to my calculator, with a 12" mounting height difference between the low beam and fog light mount, the top of the beam would only reach the height of the low beam headlight after 300 feet, at which point they're producing under 5 lux. Now like I said, I wouldn't aim any low beam lights above legal limits, but I'm curious if they would glare if they were.
- I believe I've read that rigidity is a problem with bumper mounted lights, so is this a reason this kind of auxiliary beam is a bad idea? If they were to be secured to something more rigid, would it make a difference? If they were aimed significantly lower (and be mostly useless, I guess), would the flexibility of the mount still be a problem?
- So I've read all the concerns about the uselessness of fog lights. Given this, and since the bi-halogen lights are as cheap as 150$ for pair, would using them as independent fog lights mounted quite low be at all useful? Since they're full compliant low beams, and if I were to wire them to work without the low beam on, could they function as fog-only lights?
- Or, could I use the bi-halogens fixed in high beam, or use the 90mm performance halogen high beam as auxiliary driving lights? Still too low for this function?
- What if i angle them a tiny bit outward for a broader beam pattern as static cornering lights? I guess I'd have to lower the driver side to have the right side cutoff be under the VOL aim height, but otherwise it could be helpful. I believe I've even seen a similar suggestion from one of the mods in an aux low beam thread.
- I've been spoiled by the AFS HID lights in my previous car, and have always been curious how they work and if it is even remotely feasible to reproduce something like this.
- As much as I'd like to, I'm not suggesting retrofitting a rotating AFS system inside the headlight, plus controlling that system successfully via off the shelf parts sounds next to impossible.
- My other idea is to use the 90mm bi-halogens as a fixed AFS system. I've read in a Valeo brochure about the mythical existence of a system in between rotating AFS headlights and <25mph fixed cornering lights. It uses some sort of outward mounted lights with a beam profile akin to low beams, and activates selectively based on cornering.
- I've seen something similar suggested by one of the moderators, except using fog lamps with a similar beam profile to low beams facing outwards wired to come on with the turn signal. Not sure if my concept is similar enough or if it goes over the line...
- If the 90mm projectors were mounted pointing outward at the angle suggested by Valeo (somewhere between 15 and 30 degrees), and used something like the Hella Dynaview control module to switch on based on steering angle and yaw rate, and then switch off on a timer, I believe they could work as fixed curve-adaptive lights.
- What are the regulations on curve-adaptive lights, and how impractical or non-compliant would my idea be? Would it be better if they were 90mm fog lights, but preferably ones with slightly more distance than the usual junk? Is operation of these kinds of fixed lights illegal above a certain speed?
- Would the regular 90mm Hella Dynaview Evo2 cornering lights be at all useful outside of intersections? I know they only function under 25mph, so that rules out all but the slowest curvy roads. Is this limit based on any US regulations? Would raising it slightly, to say 30-40mph, harm my vision at all on dark curvy backroads? Obviously the beam pattern is part of the limit, but at slightly higher speeds than 25, wouldn't any light that shines on the inside curve ahead be useful given that the headlights are still pointing to the outside shoulder?
- I know Daniel Stern suggests moving the DRL function to a different unused front light (can't remember if it's the turn signal, front marker, or parking lights), and I'm interested in this to preserve the lifespan of the low and high beams.
- For some reason the Subaru uses the low beams as DRLs, so in my opinion even using the high beams at lower voltage would be an improvement. It also has seemingly useless parking lights that only function to drain the battery if you accidentally hit the switch on top of the steering column. What would be the best solution that would maintain DRL function?
- I don't know exactly what the DRL system is on the Spyder, but I know the facelifted headlights have a parking light and a turn signal at least. Does anyone know what the best option for that car would be?
- With the MR2 Spyder, I'm lucky to get two compatible headlight options in case I need or want to replace them.
- I would likely replace them given the terrible oxidation on most of the cars I've checked out. Even if they were in fine shape and could be restored, I could get slightly better performance with new ones, and I would have the option to choose the other type of light with a different optical system if it were better
- So I'm curious which light would be better. The early headlight is a large H4 reflector, and the update uses an H7 low beam projector with a 2.5" lens and a 9005 high beam reflector
- Anecdotally and via general info about reflectors versus projectors leads me to think the projector would be better, and it has the benefit of using both beams on high. They are 500$ a pair though.
- Given the size of the headlight and reflector, I have a suspicion the H4 reflector can perform pretty well. It also has the benefits of having many high performance and overwattage bulbs available, as well as being 150$ per new assembly.
- But I have absolutely no firm information of any kind. No one has tested these (publicly), no one has even compared these with a luxmeter or even with wall shots. Even the recommendations on forums merely say the facelifted lights are much better, but don't even go into detail about the beam pattern or performance on the road. I guess that's the downside of a rare platform. Miatas have no end to forum posts about minute specifics and some pretty technical information (and you know, the 7" sealed beam and all the options for that).
- With a low gauge wiring harness, the best bulbs, and new or restored headlight housings, what kind of light output, beam distribution, and performance should I expect? Are lights engineered 20 years ago comparable to modern halogen lights? Lower end LED lights? Would they tend to have more distance visibility or a wide output? Any info or even impressions would be helpful.
- There's not much good info about halogen bulbs. I suppose there's not much about HID capsules either, but when every crappy LED "bulb" maker publishes (admittedly inaccurate) detailed specifications on their products, the halogen bulbs seem even less described by comparison. Most of the time all you get is a +XX% vision and that's it, and only niche forums ever test them to find out if the claims are true, and even then it's often only peak readings. So I have a few questions I haven't been able to find the answers to.
- I've seen Daniel Stern's bulb chart with the flux outputs, and find it helpful to refer to whenever I'm researching specifics. But it is still very general information, and there's no specifics about rated bulb lifespan, rated flux by brand or performance line, filament dimensions, capsule dimensions and pressure, etc.
- As far as I know, those features are what determine the actual intensity increases in a headlamp, due to higher luminance and a smaller filament approximating a point source better. Is there anywhere to find this kind of information or is it all proprietary?
- Also, is it safe to generally assume that increasing any one of the factors will improve output: increasing flux with no other changes will get more intensity everywhere in the beam; increased (native, uncoated) bulb color temperature means a higher filament temperature and higher luminance; smaller filament means more luminance and higher peak intensity; smaller capsule and higher pressure means higher filament temperature, color, luminance, and peak intensity?
- How do bulbs compare to each other. I assume that besides the single/dual filament and axial/straight bases, there are other considerations by which manufacturers choose their output source. Given that an H7 is newer and has a higher rated flux than say an H4, does that mean the technology and performance are better by definition?
- Also, given the ability to create high flux bulbs like the HIR1 (the modern, non infrared reflective ones) or H9, is the only thing stopping lighting manufacturers from building higher flux and luminance versions of other bulbs the bulb ratings for compliance, and not technological limitations or compromises?
- If the above is true and the limit is legality, how come bulb manufacturers don't create high performance "off-road" bulbs with the exception of the H7 Rallye and maybe the H7 RacingVision (which I think is only compliant in certain countries). Clearly there is no issue with building overwattage bulbs, and most people actually researching such upgrades wouldn't mind the technical non-compliance if given a safe-ish significant increase in intensity and flux.
- So the other half I don't understand and can't find many resources on is the headlamps itself, as well as the optics involved.
- I'm a regular on BLF and reddit's r/flashlight, so I know about the basics of reflectors, TIRs, and aspherics, as well as their optical efficiency, approximate amount of light collected and how well it's colimated, and the correlation between optic diameter (and depth to a smaller extent) and its ability to produce higher candela values.
- I just don't know quite how to apply it to headlights. I've found Hella's page that says free-form reflector optics capture as much as 45% of the source light, and then only 90% is actually reflected, and 85% passes through the headlamp cover. Similarly, I believe the numbers for projector optics (in high beam I believe) are 52% of the light captured, but an additional amount lost since the aspheric lens only allows 90% or so through.
- Now if those numbers are anywhere near accurate or universal, all that addresses is the amount of flux that actually is directed onto the road. How intensity is distributed is another question. I've seen the diagrams and ray tracing images of what areas of each type of optic deliver generally which section of the beam pattern, but I have no clue what kind of differences in design affect the final beam. Is there anywhere I can find this out, or a general explanation of what constitutes a "good", broad, or high intensity headlight optic.
- One thing I learned that was interesting and super obvious after the fact is that since projectors output the same intensity as reflectors through a smaller area, they appear much brighter when viewing the lamp from the front than reflectors, even if they deliver the same intensity in a certain point.
- I'm curious what the consensus (or lack thereof) is on the best beam pattern for driving, beyond decades old compliance test point minimums.
- Daniel Stern's paper on glare mentioned that while generally bad for distance vision, when people use their fog lights for foreground lighting, they tend to keep their vision up and looking further due to the feeling of security. Given how many people drive like this, is there any validity to this concept and would a larger, but still balanced, amount of foreground light be potentially helpful to average drivers?
- In addition to the above, given how many people drive around other cars, and given the increase in glare, is it worth trying avoid dilation of the pupil in response to foreground light if it's likely happening a lot anyway in response to the glare? I know it's hard to keep looking at the distance when every few seconds I have to slow down, stare at the shoulder line, and hope I don't die because an LED equipped truck or SUV is passing by? I know an arms race of brightness isn't ideal, but if it's already happening, wouldn't a proportionally brighter foreground and distance be valuable? And isn't this the idea behind the "town beams" on European ADB systems?
- I've read a decent article by a lighting engineer about the ideal gradient of light for visibility. It's basically increasing the candela value exponentially compared to distance, to keep the illuminance of the road consistent. Does that sound like the optimal beam pattern or should it still be balanced to be perceptually brighter in the distance?
- In my personal opinion, the top 1 degree of the beam is most important, especially on low cars because it determines distance vision. Given that most cars provide more than adequate brightness in the foreground and between 1-2 degrees down, in the near-but-not-foreground area, why isn't there more focus on increasing intensity past 100 feet or so, depending on aim and mounting height. Especially with the increased speed limits since the regulations were set.
- Are there any kind of headlamp optic, or manufacturer, or even aftermarket part that can increase the intensity near the top of the beam, even if it comes at the expense of light closer to the car?
- Where to find resources for research. I've read just about everything I could find by Daniel stern, I've browsed through half the threads in this forum, gone down multiple Wikipedia optics/light article and US regulatory document rabbit holes, and filled up my google search history with headlight related queries.
- Still, I see people throwing out information like it's common knowledge, and I have no clue where they get that.
- For example, I've found, and bookmarked or saved a few photometric reports on some headlight assemblies, but they're mostly SAE samples of 20 year old cars, Daniel Stern's isolux plots of various sealed beam replacements, a few failed tests demonstrating over and over how bad HIDs are in reflector headlights, and two tests on recent Morimoto projectors.
- But people here and in other forums talk about test results for a bunch of specific headlamps, although rarely reveal them. I know there must be copyright restrictions on this data, but how do certain people have access to these, and is there a way for me to do so without submitting a few hundred headlamps to Calcoast or bribing an automotive lighting engineer?
- Is there also general headlight engineering knowledge I'm unaware of? I see people here and lighting engineers discussing how a light should perform, based on just seeing a picture of the light.
- For example, the Tacomaworld poster linked in a sticky mentioned how the large H4 reflector in his truck should outperform the H11 projector in the next generation. Based on what I've been able to find, in this case, Hella's tech articles on headlamp systems, low beam projectors capture more light for the beam than reflectors. Plus an H9 produces more flux than even a high wattage H4 low beam (in this example). I know also that there's more optical efficiency loss with the projector given the addition aspheric lens it passes through. But how can one actually take an educated guess at what kind of performance a headlamp should produce?
- Another example is a thread here, in which Virgil mentioned how the larger high beam reflector in the 2002 camry headlamp, even with its non-round shape, should outperform the 2006 headlamp with its smaller diameter high beam. And later in that thread, he mentioned that for the 2000 camry, the (still compatible) European spec H4 headlamp is better optically than the identically sized US version. Is this based on photometric tests I don't have access to? Is this an educated guess based on optical factors I'm not aware of? Or did I miss something in that thread that explained why one is better than the other.
- I've read about (for example), the different methods available for designing a freeform multi-faceted reflector headlight. And the engineering and software behind it is incredible. But while it's nice to know the different methods that can be used to create the shape and location of the reflector segments, but I can't apply this to any real headlights because I have no way of knowing what method was used. I don't know of a way to determine which method was used to design a certain complex reflector, nor what attributes contribute to its performance beyond perhaps its size.
- Headlight retrofits
- The forum sticky and Daniel Stern say that theoretically they could be done well, but it's harder than it's describes. I agree that most retrofits are low quality, and usually tend to be worse in terms of performance (the Morimoto Mini H1 projector test is hilariously bad compared to what people say about it).
- I'll start by saying that while I've spent a fair amount of time (for lack of better information) researching a retrofit, given the difficulty of doing it properly and the performance I could theoretically achieve with the stock lights and possibly auxiliary/cornering lights, I'm not planning on a retrofit. If I were, I would definitely consider all the concerns raised here before even thinking about starting anything. So, I'm hoping this means I can discuss this as a concept, and not as a request for guidance. It's also because I'm curious about this topic having read a fair amount about it, and since the sticky post doesn't answer all my questions on the problems with retrofitting headlights.
- Given photometric simulations of a projector (for example the M LED 2.0, which is the only one I have relatively complete data on), and assuming a 15% cover lens absorption, what other factors can make the resulting output non-compliant?
- By the way, I followed the launch of the M LED 2.0 pretty closely and I'm curious what people's thoughts are on it. There's instructions to make it pass the .86D, 3.5L maximum as well as to provide more light above the cutoff. While I don't agree with the choices, nor the color temperature and cutoff sharpness, those non-compliant test points were designed on purpose to appeal to people's subjective impressions. Besides those (fixable) test points, and given the comparative breadth of information available about it compared to pretty much any other OEM or aftermarket projectors, I don't see what would make it an unsafe and ineffective lighting solution.
- What about OEM projectors, such as the great Koito Bi-LED (both anecdotally, in a test for which the numbers are not available to me, and in the IIHS's tests). They perform well even with cover lenses, and the lenses on the Spyder are not a very complex shape. Beyond some chromatic aberration, wouldn't the refraction enter and exit the lens at the same angle? Even if it didn't, as long as the shift from refraction was consistent through the beam pattern, couldn't the shift be adjusted by reaiming?
- I understand the issue with the mounting method most people use - cutting out parts of the reflector and epoxying the projector into it is not a good solution for something that has to be so stable. Based on some images of an opened headlight that I've seen, the Spyder's projector is part of a bracket to mounts properly. Given this, wouldn't removing the projector parts and attaching a new projector to the remaining brackets be as secure as the original, and it could maintain the aim and vertical/horizontal location?
- I know why you blanket ban retrofits, although I personally think discussion and information on the topic would be more persuasive than just having every post questioning it deleted. It's not my forum, but I do find I appreciate when "there are no stupid questions", because we all had to start somewhere. Without much available information, it took a long time and a lot of research to get to the point of understanding I have now, which apparently is just enough to understand that upgrading the stock lights safely is the best I can reasonably do.
- I've seen how most retrofits are performed, but is there no way to perform one well without industrial tools and manufacturing? If mounted securely and with respect to center of mass, sealed properly, using an OEM projector that complies with photometric regulations, the end result aimed properly, and then the ~20 test points verified with a full spectrum lux-meter at 25' (particularly the glare points), would this still be unsafe?
- This (among other things) might get my post deleted, but I'm curious why certain halogen upgrades are allowed, since any discussion of illegal or non-compliant upgrades seems to be against the rules. I'm pretty sure HIR upgrades, Rallye bulbs, and overwattage lights aren't exactly road legal...
This turned out incredibly long. Sorry about that. I could break it up if needed, or pare it down if needed.
Thanks. Hope I get to learn something and make good decisions once I get my hands on some upgrades.
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