Chill out guys. I'm not in competition or arguing with anyone. I go to this forum for the very reason that there are a lot of knowledgeable people on it.
But consider the possibility that I spent 30 years as an engineer, and lawyer, and didn't just fall off the turnip truck either.
Since you've apparently come to the defense of your original post, we're just arguing the case with facts to try and get you to see what the facts are regarding the use of 9007 bulbs in a housing designed for a 9004 bulb.
If you've been an engineer and a lawyer, this should be even easier.
I'm simply doubting that this particular 9004 -> 9007 conversion is illegal and unsafe. I don't believe this to be the case.
There is no federal law that prohibits an individual from making this modification. And local and state laws are pretty non-quantitative
and basically consist of avoid "glare" (as though that was a hard spec), and regulating the mounting of DOT-approved offroad lights.
Anecdotally, I see plenty of new cars on the road today with fully-legal OEM HID headlights that have much worse "glare" than my old Ford.
Just because there is no federal law that deals with individuals using bulbs in headlamps not designed for them doesn't mean it isn't illegal. There are Federal Motor Vehicle Safety Standards, and State and local police have the power to remove a vehicle from the public roads that violates those standards. It's certainly true that most law enforcement are absolutely clueless about such things though, and you could probably drive around for years with blue HID bulbs that blind everyone before you'd encounter a cop who would pull you over for it, let alone inspect the bulbs or headlamps.
On some level, this is just about not being a jerk, and caring about your own safety, as well as the others on the road. Even at a selfish level, drivers should have an interest in not having the headlights of their vehicle glare into the eyes of the drivers of oncoming cars, lest they be blinded and drive into the vehicle with the headlights that blinded them.
I am well aware that if you took a modern headlamp and replaced the bulb with another type it would be extremely unlikely you would get a optimal beam pattern. That is not the situation here.
The stock Gen-1 headlight design from 1990 is hardly some sophisticated multi-faceted compound reflector design that shouldn't be meddled with.
The composite headlamp on the Explorer is every bit a modern headlamp. Even headlamp designs from the 1980's, 70's, and a long way back are very sophisticated.
The 1990's were not ancient tech just because newer headlamps use a different reflector and beam design, nor is that any justification for using different bulbs.
I did originally measure my Explorer with the stock 9004 bulbs. With a lightmeter from the lab. And if you saw the beam pattern you would seriously doubt that it was some kind of optimal design. Changing to the 9007 bulbs, the beam pattern was not some even worse chaotic mess.
It was narrower, with less side-scatter, and a decent pattern that would easily meet the criteria of CFR 571.108.
It would have been interesting if you used a light meter, and measured the intensity at several points in front of the vehicle, as well as higher up, 1,2,3 meters off the ground. Then maybe you'd get an idea of where all that extra light is going.
And I did adjust the enclosures down a bit, Anime, to compensate for the lower reflector.
So now the high beams are compromised so they won't be as functional when you need them. Also unsafe.
I am also well aware this mod has been tried on numerous other car headlight designs, ad nauseum, and shouldn't be done willy-nilly without evaluating the end result.
Consider the possibility it does yield an acceptable result on some older headlight designs.
It might be 'acceptable' for off-road use, where beam intensity is the only consideration.
Sure, MAYBE the beam pattern is sort of acceptable, IF you aim the headlights down more, to the right more, and make all sorts of other adjustments to compensate. But having to do those things should tell you something is wrong, that you're doing shadetree modifications to a precision optics system in the hopes of some minor improvement to the brightness of the low beams, regardless of anything else.
If you want to use the increase in brightness of the low beams after adjustment as the sole measure of benefit, sure, maybe you achieved some little tiny bit of increase in beam intensity. But at the cost of the function of the rest of the system.
The misinformation about this sort of bulb swap leads people to simply move wires or use adapters, throw in 9007 bulbs, and then drive while having headlights that glare straight into the eyes of other drivers, not caring since now they have "20% brighter" headlights.
These days, every ricer on the planet has rigged HID bulbs into their halogen housings, and we have the same problem. Glare, glare, glare, all over the place. And they don't care, they just think it looks cool with blue tinted headlights, and they believe they can see better because all the glare everywhere makes it look like there is more light, when what little light there really is, is scattered everywhere but on the road, where it needs to be.
Have you tried using high-output 9004 bulbs with the relay setup instead?
My experience is that 9004 XtraVision or Hi-Visibility bulbs give an improvement, and maintain the benefits of the original headlamp beam pattern. While some people may not consider it optimal like the SAE pattern with a sharp cutoff, I think the much longer throw suits an SUV better. A pair of high output 9004 with a relay setup might even outdo a pair of 9007s with stock wiring.
While the 9007's are "better" bulbs in a lot of ways, with the axial filaments and higher wattage low beam, the 9004 is still decent, and works well for what it was, a compromise for a composite headlamp with long bulb life and lower power consumption.
If they made aftermarket housings for the 91-94's that were designed to be used with a 9007 bulb, that would be an improvement, but they don't, so the easiest, safest thing to do is stick with 9004 bulbs, and use higher output versions and relay harnesses to achieve the maximum potential of the headlamp.
