Thor X Colossus, modded to HID - v poor beam quality - advice please?

[TallNHairyDave]

Hi folks

I've modded a Thor X Colossus to a 35W HID, and while the mod was simple to do, I've hit a problem with the quality of light output...

In short, it's got the sort of bright flood that I'd expect to see (having seen photos of other people's modded Thor beamshots), but the small tight hotspot that is visible when I shine it on the ceiling at home (8 foot celing height) completely disappears when I do a horizontal beam test at some trees about 200 feet away. Definately NOT what I'd expect to see. There's only really a hotspot visible if you shine it at the ground up to maybe 20 or 30 feet away.

The beam pattern is more like the bad old maglite days with a big dim hole in the middle of the spill where there should be a nice hotspot, and this makes me think that it's probably bulb position in the reflector, but I thought I'd ask the experts for some advice.

The Thor's reflector takes H4 bulbs, and comparing the metal base on the original Phillips H4 bulb to the plastic(?) base on the HID bulb it's obvious that the HID isn't going to sit as far into the reflector as the Phillips.

The locating tabs on the H4 are metal and about 1mm thick, but the ones on the HID are closer to 3 or 4mm thick. I'm assuming that this means that the hot spot of the HID bulb is going to be at "not quite" the right point in the reflector for the reflector to give the proper beam pattern?

Would it be worth me trying filing down the lugs on the HID
so they are the same thickness as on the H4 bulb?

Thanks a million for any advice. :thanks:

Cheers

Dave

 

[TallNHairyDave]

Okay.

Scratch the thought of filing down the lugs on the HID bulb.

Just had a better look at the reflector and the central hole is not large enough for filing the lugs to make any difference because doing so would not let the bulb come further forward into the reflector anyway.

So.... Anyone got any ideas why the beam pattern is so crap with the HID fitted?

If I can't get this to work, I might revert the Thor back to the H4 bulb and flog the HID ballast and bulbs. :scowl:

Cheers.

 

[TallNHairyDave]

Just swapped the H4 bulb back in, and the difference is scary. :mecry:

Shining on the same trees, the H4 bulb puts a bright spot on them, where the HID was barely lighting them up at all (illumination on them was mostly from spill light rather than a spot).

ARRRGH

 

[Stereodude]

You need to make sure the arc in the HID is in the same place as the filament in the Halogen H4 bulb.

 

[TallNHairyDave]

You need to make sure the arc in the HID is in the same place as the filament in the Halogen H4 bulb.

Thanks mate.

Any suggestions how?

I've spent a frustrating couple of hours tinkering and I can't see a way to get the HID bulb any further into the reflector (as it appears to be a little too far towards the back)

 

[plasmaman]

Dave
Pics would help.....
I used D2S bulbs in my HID conversions of an H4 light and that was not difficult to adjust to get the right height. I can see the hotspot on trees at 1000 feet.

 

[DM51]

Dave, just a guess, but if it's focusing into a spot at short distances up to 20 ft, but not any further, the bulb is probably seated too deep into the reflector.

If it was too shallow, i.e. the bulb only just peeping through the hole, you wouldn't get it focusing at any distance, as the beam would diverge from the start.

Try backing it out a little and see what happens - you could use a few washers or something as spacers/shims just to test, until you get it right.

You probably won't need to move it very far to make a noticeable difference.

 

[TallNHairyDave]

Plasmaman - sorry, forgot to take my camera with me when I was doing the horizontal beam test, but here's what the beam looks like shone up on the ceiling at home...

DM51 - looking at the HID in place it does look too shallow in the reflector compared to the H4 bulb. But that's possibly just an illusion because of the difference between the two bulb bases, so I didn't think that it was maybe too deep in! Thanks for the suggestion - I'll try shimming it out a bit and see what happens.

 

[yellow]

that very short distance try is useless - when a throw is needed.
do a comparison with the H-bulb: at close dist., there will be a "tunnel", or "ring", no hotspot. The light dot comes, when the reflected light spreads a bit, further away.

the arc has to be placed deeper into the reflector, exactly where the filament has been.
Why should the reflector work in any other condition?

Is it not possible to mod the reflector itself? Maybe widening the hole, or such?

 

[TallNHairyDave]

Here's a comparison to the H4 halogen at same distance

 

[scott.cr]

Try backing it out a little and see what happens - you could use a few washers or something as spacers/shims just to test, until you get it right.

This will be an easy and low-cost way to do it. I have to warn you to not hold the lamp in place by hand!!! The Thor's reflector is metal and you can short the HID capsule's exposed wire against it. Also, if the dielectric on the wires is compromised, you can receive a pretty hard shock simply by holding the lamp.

It is tempting to disassemble the light, fire it up and slide the lamp in and out to find focus... but it only adds about 30 seconds per try to use shims or layers of tape.

 

[TallNHairyDave]

Well, I backed the HID out using spacers and testing, and it took quite a lot of backing out to get a good throw and hotspot (ended up with about 4mm thickness of spacers)

I've now used JB Weld to fix the spacers permenantly in place and am working on a home-made bulb retention clip which will screw onto the old bulb retention bracket and hold the HID bulb base thoroughly.

Thanks to everyone for the help.

 

[JacobJones]

I know I'm 3 years late but is there any chance of the beamshots mentioned in the other thread about this?

 

[Essexman]

I know I'm 3 years late but is there any chance of the beamshots mentioned in the other thread about this?

Looking at Dave's profile shows he's not been on CPF for a while. But I know where to find him.......

BTW welcome to the forum JacobJones.

 

[DFiorentino]

I know I'm 3 years late but is there any chance of the beamshots mentioned in the other thread about this?

If it matters, here is what I did...link.

-DF

 

[JacobJones]

Thanks Essexman. That could be helpful DFiorentino, I intend to mod one of these to HID