Octane

****This is what I posted as a reply in another thread, but I thought it would make a good discussion topic since there seems to be a lot of assumptions without much actual, direct, objective comparisons between the two****

Regarding the EDM vs JDM comparison....

All headlight lenses are glass. The difference here is that EDMs have the glass as the outer layer, while the JDM (and USDM for that matter) have the glass lense just behind the chrome bezel all housed behind the plastic.
Here is a pic of my JDM headlight (you can see the glass lense behind the plastic).


For a full sized image of the picture above, click here:
http://www.imagestation.com/picture/...6.jpg.orig.jpg
Then compare the full sized image to this EDM picture located in the 2nd post of the link below and look closely at the lines on the glass lense of each:
Jdm Headlights - Edm Headlights

Your comparison should look like this:


Based on these images, I suspect that the JDM and EDM beam patterns are very similar. Both show a marked improvement over USDM headlights. Here is a picture of my jdm/hid beam pattern:

Now keep in mind this is with my crappy camera phone - in real life the beam is more even and the cut off is sharper. Also, it looks brighter on the left because I'm closer to that wall.

I would really like to hear objective remarks from someone who has personally owned or driven cars with both EDMs and JDMs installed. My theory is that both have very similar optics and will perform equally well.

USDM seem to have 2 main problems that contribute to their subpar performance - poorly designed optics (glass lense) and clouded clear plastic cover (hazing and chipping from road debris damage). I don't know if JDMs use higher quality clear plastic, or if they have simply been exposed to far less damage during their lifetime, however I found that my JDMs were in near perfect condition when I bought them 1 year ago, while my USDM headlights had to be wetsanded and polished to remove most of the hazing (from 285,000kms of exposure), yet never came out perfect.

Perhaps the one advantage the EDMs might have is the lack of chrome trim. This reflective trim might be refracting some of the light in random directions causing glare from USDM and JDM headlights?? If this is true, I'm sure its minimal based on my experiences with the JDMs.

I believe that those who have gone from USDM to either JDM or EDM have both seen a dramatic improvement due to better glass optics (and clearer plastic on JDMs). The problem is that there are so few sets of EDMs in N/A compared to imported JDMs, that there are few here (if any) who have experienced both and who are therefore truly qualified to state which is better (JDM or EDM).

As well, there is a tendancy for people to promote what they have over other options, even though theirs may not be any better. For example, an EDM owner who once had JDMs and saw little to no difference between them may still try to promote the EDMs as a superior headlight option to justify to themselves the expense of switching....

Objectivity here is the key to an honest answer.

Thoughts anyone?

For the record, I tried to get a set of EDMs for my car (swap with MikeD), but it never panned out. Then a set of JDMs basically fell in my lap. I originally wanted the EDMs for the (reportedly) superior optics, even though I preferred the look of JDMs. When I installed my JDMs I was blown away by the improvement in beam pattern and cutoff - its not as good as projectors, but far better than USDM (see pic above). With the improvement in beam pattern and my personal preference in appearance, I'm very glad I got the JDMs.

(for those interested, I have more pics on my gallery page: Octane's 1994 Granada Black Pearl LS Coupe )

Dave

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MLC

excellent arguement, I have yet to drive with my JDM's but as far as I can see, when my lights are turned on the beam pattern appears to be 10x better than USDM with little to no hot spots. I would like to see how much better the EDMs really are.

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Gerald

Great topic Dave!!!!!!

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Octane

I just get the impression that those who have EDMs (at great expense and or difficulty and/or luck) are so quick to sing high praises of their performance (and rightly so). The problem is that there is nobody to objectively confirm or deny that they are "the best" optics available (oem) for our cars.

People just hear that they are hard to get, expensive, and come from a part of the world where headlight spec. requirements are very high. Therefore they take the words of EDM owners as gospel. It is possible that headlights from other parts of the world (Japan for example) are *just as good* performance-wise as EDM optics.

....think about it. You are a *japanese* automaker creating your *flagship* car for your home country. Wouldn't you make sure that the very *best* goes into that car??

I believe the JDM lenses have the best performance (on par with EDM) and the best looks (USDM class/flash + 1piece design) to appeal to Honda's most important market, Japan.

This is just my theory. I do not know if JDMs perform as well or close to EDMs, but the evidence suggests they might.

Aesthetics is a matter of personal preference, however if majority rules, I suspect most would say the one peice JDMs are most appealing (rememeber we are talking just looks, not performance or the desire to own something more rare/exclusive).

I'm hoping there are a few members here who have experienced both headlights and will comment.

Others who wish to share their view are more than welcome to chime in.... I want this to be an open discussion!!

Dave

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B+O

no hates, but i honestly dont recall anyone saying the EDMs were better than the JDMs...if anything i hear nothing but praises for both.

In true fashion however, the EDMs are more suited for US roads. i believe i have read that statement more than "EDM is better than JDM" style arguements. the design of the ECE marked (European) light for the most part is universal, meaning that the pattern is made to illuminate equal ammounts on both sides of the car.the DOT labeled light is like this hazzy looking blob of a beam pattern that was made like such because of US's requirement for lighting ( a specified amount of glare for lighting street signs) honda did not want to deviate because the manufacturers of cars can be sued to great lengths if their lighting prooves to be the cause of a major accident (manufacturers are starting to get more lax on this however)... The JDMs however were (from all accounts) made to perform on the left side of hte road, therefore you get light raised up and into the eyes of on comming traffic since we drive on the right side of the road.

And honestly, i like the USDM headlights the best, second is the EDM (design wise)

there's something about the JDMs that just rub me the wrong way on hte sedan, they dont look very good.

Legend93

This is the best answer so far. The lighting pattern on JDM, EDM, USDM are all dependent on local laws. Typically, JDM and EDM cars are driven in crowded urban environment, which means there are a lot of oncomming traffic. Their laws require their headlights to have a sharp cut off to prevent blinding oncomming drivers. To still allow drivers to see road signs, the light output is slightly bias toward the passenger side. This is why when you install a JDM/EDM (especially right had drive cars) headlight, the left side is usually brighter (Also quite blinding to our oncomming traffic.).

USDM, usually referred to as DOT (Department of Transportation) approved headlights are designed for the open road of the U.S. The law requires that there be enough light bled away from the main light pattern to light up signs and objects far away. This is also why DOT approved headlights seem a bit dimmer than their EDM/JDM counterpart because a portion of the light is being diverted outside of the main focus area to light up road signs and far away objects. This leaving less light in the main focus area, making it appear dimmer (and our interpretation - not as good as JDM/EDM).

Octane

By that theory, I should be glad I have the chrome bezel around the headlight to scatter a bit of light in random directions and light up road signs above me (which they still do, esp thanks to the higher light output from the HIDs).

edit: another thing. If this light spread above the area of focus is required by law to light up road signs, why are so many cars now sold in N/A with projectors that produce tonnes of light down low, but have a crisp cut off that prevents light from spreading upwards towards overhead highway signs??

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Octane

One other thing, is it just me? or do others see the resemblence between the EDMs headlights and integra headlights of the same era??

I'm not knocking them, I just noticed that the EDMs on MikeD's car looks alot like my buddy's black 93 teg coupe headlights....

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Legend93

The DOT headlight laws were written during the days of sealed beams, when all cars sold in the U.S. were using the same lighting units. When DOT relaxed the laws to allow free-formed headlights, manufacturers began to use headlights as part of the styling element of a car. However, the part of the law dealing with beam pattern and wattage has not changed. So, we continue to have headlights with a main focus pattern with a portion bled to the periphery for road signs/objects and a max. wattage rating of 55W low and 65 watt high beams.

As the auto industry got more globalized, it became more difficult (read more expensive) for the auto industry to make parts (including headlights) to satisfy all the laws in different parts of the world. Since the EDM & JDM headlights can satisfy the majority of the DOT law than vis versa, some manufacturers just decided to begin addopting those standards. Law maker in the U.S. knows about this and they also realize it is extremely hard and expensive to enforce. So, as of now they just turn a blind eye and has been accepting it for the past decade. Well, if they don't enforce it, it must be legal. At least that's the general thinking now.

A few years ago, there was a big debate about whether HID should be banned becaue at certain situation, it can temporarly blind oncomming traffic. Just as many people complained about HID, there are equal number of people who support it. So, the debate has settled down for now. We'll have to see when it'll surface again.

Sorry, for the long history lesson. This is just general info. I've gotten over the years from reading columns from Car and Driver, Road and Track, ....etc.

Octane

Hey, don't apologize - that is all great info!!

I love learning like this

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B+O

the Projector beams of the newer acura (read japanese USDM) are set almost like the DOT style. the middle of their beams are diverted upwards (i was getting power sprayed by a TSX's lowbeam projectors the other night) and as i got behind it i couls see the pattern on the surroundings. though it wasn't as high as mine you could clearly see the cut off was higher in the middle. i have yet to see a beam pattern from these cars, sprayed onto a wall, but if what i witnessed was correct by the way it lit up road signs, it would have a considerably higher centersection than the outter cut off. which would somewhat mimic the DOT style headlamp designation. im not sure so i have to look at it on a wall to be perfectly sure.

the JDMs lighting up roadsigns is what it's supposed to do, the dont have a super crisp "cutoff" it actually is designed to scatter light upwards as well, just not as much and in only one general direction. the EDMs scatter light ot the right, and the JDMs scatter to the left, USDM scatter like all different types of directions. i wouldn't be surprised if it scattered backwards

now about the HID thing, this is very true. people complaind complained complained about HID and those 80/100W super dooper bright Hypewhite lights. but when it came down to it, HID has proven itself on more than one occassion to help visibility. now i do think they've regulated the color temperature, but they have not regulated the use of HID i'll have find out that.

B+O

i suck at explainations so i had to get scour the net for pics to basically show you what i was talkin about:



that's what the beam normally is associated with for every country. ECE the "harmonized" which is what most companies are using now days.

Legend93

Appreciate the research B&O! Nice job!

ChrisK

Well, I personally had all 3 Legend lights with HID retrofits. Anyway, forget about the USDM. Personally I think the European lights are the best. Between the JDM and EDM I personally like the looks of the JDM the best and the beam pattern of the EDM the best. I ended up with the EDM. Now this could just be my car and my HID set up, but either way, the EDM with HID came the closest to an OEM HID beam pattern. I'm not saying it was as good as OEM, but of the three headlights it was the closest on my application.

ChrisK

[quote=Bang&Olufsen DK]i have yet to see a beam pattern from these cars, sprayed onto a wall, but if what i witnessed was correct by the way it lit up road signs, it would have a considerably higher centersection than the outter cut off. which would somewhat mimic the DOT style headlamp designation. im not sure so i have to look at it on a wall to be perfectly sure.
QUOTE]

Speaking of beam patterns on the wall. Have you ever seen the Lexus RX330 projector HID beam pattern on a wall? I have to say I personally think it has one of the sharpest and flattest cutoffs that I have seen. I'll have to take some pictures but I'm thinking of using the RX330 projectors for a retro fit rather than the BMW projectors. It does still have the stair step, but it is so sharp. When I get the picture I'll post it up for you.