MainePorsche

Rog,
Anything on these ?

ROG100

We used an H4 lens removed from a new H4 assembly for the mold. Mold is being made (I think that is what they call it).
Holiday got in the way so hopefully next week we will have more progress.

MainePorsche

We thank you.

DKWalser

Just a note of caution: While I hope Roger's efforts pan out, I doubt that they will. There are at least three important variables that determine how well a headlight works: the lens, the reflector, and the light source. A new lens only deals with one of those three variables. My understanding is that the 8" H5 reflector is an extremely poor design. Covering that reflector with a replica of the 8" H4 lens might not measurably improve performance -- in theory, it could make things worse.

The H4 lens was designed to work with the H4 reflector. Expecting that lens to work well with the H5 reflector is a bit like taking the lens off of a telescope and expecting it to work on a 35mm camera. Sometimes it works. Usually it doesn't. Unless the H5 reflector is very similar to the H4 reflector, the H4 lens is unlikely to work well with the H5 reflector.

But it might. I hope it does and I'm grateful to Roger for being willing to experiment. I just don't think any of us should be counting on this as being the answer.

ROG100

Hi David,
We are changing two of the variables - the light source and the lens. I guess we need to look at the difference of the reflector H5 to H4 - are they that much different? Within the confines of the headlight size I can't see them being that different.
As I am already deep $$$ into this project I will see it through.
The outcome has got to be better than a standard H5 - anything WOULD be better 8>)
Roger

Ducman82

This would be better

Koenig-Specials 928

If Roger is successful with a replacement lens kit I might be tempted to remove my 25+ year old lenses and slap one of these inside the housing and then replace with a new lens.

Note: No affilation to FXR

DKWalser

Roger -- I really hope that you prove my fears were misplaced.

jcorenman

Roger, did you test that glass H4 lens on a H5 reflector assembly? I think that would be a good test-of-concept before diving into making a mold. Making a mold is time-consuming and expensive, but if a glass H4 lens on a H5 reflector assembly won't work, then a molded replica isn't likely to work either.

Please don't misunderstand, I really hope that it is this simple. But I agree with David, there are more differences here than just the lens.

If the intent is to use the H5 LED lamp then that would be the next test: H4 lens, H5 reflector and H5 LED lamp. The geometry between the halogen and LED lamps is necessarily a little different, the question is whether it makes any difference in the overall light pattern.

The only remaining variable would then be the difference in refractive index between the original glass and a new plastic lens. They won't be identical but should be close, depending on what type of plastic is used. That one can't be tested without a mold, but everything else can be.

Cheers, Jim

MainePorsche

Can any of the wise and talented take measurements of the two reflectors ?
That may answer a lot of the question.

ROG100

We made the H4 lens replacements and the difference was very good.. Way better than the H5 (not difficult).
Hopefully customers will chime in with there own experiences.

dr bob

Hi Michelle, and welcome to Rennlist.

The question on lamps in this discussion isn't about bulb selection, but rather about Roger's plastic replacement for the original glass e-code lenses. The more desirable option would include replacing the DOT blob-pattern lens with the hard-cutoff e-code lenses used outside the US. The DOT reflector shape is the unknown variable here, and whether that reflector presents a pattern of light to the e-code lens that's the same as or even "close enough" to work with the 9004 bulb that fits in that DOT reflector.

Luis A.

ROG100

Yes they are in stock - $245 each