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Originally Posted by 986Jim
...My 95 GTI VR6 I just stuck HID bulbs in the standard light and they acctually imaged perfectly on the road.....
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First I'm assuming that you didn't actually just "stick an HID bulb" into the vehicle since HID requires a ballast. If it was just a direct replacement - then we're not talking HID.
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Originally Posted by 986Jim
...Aftermarket HID lights move the ARC point so they work in a halogen housing as best as possible, however like my previous two cars they seem to glare no matter what. .
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This is simply not true. The arc tube of a halogen and HID have completely different shapes and orientations. Phillips, GE, and Sylvania don't make "retro-fit" kits - those lamps are not "arc adjusted" - they are OEM lamps designed for OEM HID optics. Period.
But say the general focal length was adjusted, the shape of the arc tube alone will result in problems. Because of this, retro-fitting HIDs "seem" to work better in projector housings since the cut-offs appear similar. But, changing the focal point changes the overall photmetrics - for the worse.
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Originally Posted by 986Jim
...Heat from an HID bulb is less or equil to a normal halogen light, it's just more focused. My last two cars had plastic headlights and the hid never bothered them at all. Halogen lights put off HUGE amounts of heat where HID doesn't really it's sort of like flourcent that way just not as cold. .
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The heat issue would be true (to a point) provided that you are using the same input watts. However, I definately wouldn't say it's anywhere near cold - grab a 50w T4 HID lamp if you want to know what I'm talking about. It's not about "focused" light - what you are seeing is the efficacy of the lamp (its ability to convert watts into lumens). Halogens have a horrible efficacy creating just around 16 lumens per watt - the rest is heat. HID is around 44 lumens/watt while fluorescent is in the 70-80's.
No matter how you cut it, retro-fit HIDs are not a good idea! Even if you discount heat (which I wouldn't), you have a serious safety concern with the ballast and wiring.
Did you install 600V - 1000V wiring rated for over 200 degrees C? If not, you've got a potential problem on your hands. HID ballasts send a high voltage pulse to ignite the lamp. Is the wiring properly insulated? Is the ballast properly grounded and shielded from moisture?
Maybe you've wired it up properly - is your "plastic" lens rated to withstand what the lighting industry calls a "non-passive failure"? That's when the lamp explodes sending molten glass everwhere. Oh yeah, HID does that.
Even if you determine that your cutoff is "good", that doesn't mean you've improved your lighting performance. Since you've changed the focal point of the optic you are likely trading foreground lighting for projection (or vice versa). There's simply no way around it - an optic is laboriously designed for exactly the lamp used. Changing that lamp changes the performance. A "better" lamp (HID) in a compromised optical system can't possibly beat an optimal lamp in an optimized system.
One last note, retro-fit kits are illegal in the US, Canada, and most, if not all, of Europe. There are no DOT approved kits (no matter what they say).