Originally Posted by ucsbwsr

A "better" bulb would be one that is new and from a high quality oem supplier like Philips or Osram. HID bulbs fade over time considering the age of the 996 if it is still running original bulbs it might be able to increase light output by 30%-50% just by swapping in a fresh bulb, this is an extreme example but certainly possible.

Here is a very basic graph to use as a general guide on what to expect with the decline in HID bulb intensity.




HID bulbs have slowly evolved over time and there are now some bulbs which offer increased output but with a whiter color (kelvin rating). The Osram CBI is a great bulb that has a strong output, crisp white color, and reasonable price point. Some aftermarket bulbs like Morimoto perform well for what they are but don't use the same high quality salts like Philips and Osram. I recommend buying from The Retrofit Source as they stock only genuine products, HID bulb knock-offs run rampant on Amazon and eBay and most consumers don't know what to look for or have the means to test the bulbs so they still leave positive feedback.


As for the ballast "boosting" I attached a PDF guide I created on how to boost the Hella Gen 3 ballasts (oem equipment on 996). For those of you handy with a soldering iron you can increase output and efficiency with a couple hours of tinkering, think of it as upgrading the turbos on your HID ballasts.

Evan




To be honest I have never seen the output of the 996 in person but from the research I have done the Hella projector fitted to these headlights is probably similar to the "E55" projector which first appeared on the W211 AMG and has been fitted to other European vehicles in that era. The E55 is a decent projector with good on-center intensity aka "hotspot" and a nice high beam, the light distribution isn't the best and the beam pattern isn't particularly wide. The common shield design on the E55 is a huge ECE-style "slope" step which is a bit odd and excessively large IMO, not sure if the 996 has the same shield but instead of a quick abrupt step which is common for DOT-spec projectors the slope is more slanted and much much longer, for reference the D2S 4.0 has a DOT style step which is pretty vertical although I think the step is too tall on the D2S, it only needs to be about 1/2 the height to effectively serve it's purpose of keeping light out of the eyes of oncoming traffic. The reflective bowl on the E55 also deteriorates quicker over time from UV exposure relative to other projectors, this bowl wear in combination with an old HID bulb can REALLY limit light output.

The D2S 4.0 is better than the E55 in pretty much every way, the biggest strength of the 4.0 is the size of it's "hotspot" instead of being a small dot of intense light it is a triangle of intensity, roughly 4-5x larger than the E55. The D2S is also a little bit wider and has a more useful beam pattern of intense light in the middle that slowly and progressively tapers towards the edges. The cutoff is flatter too which I not only find aesthetically pleasing but also more functional as light at the top of the beam pattern near the cutoff is useful for distance vision (assuming it is intense enough). The downside of the 4.0 is the excessively large step and the disparity of height between the left and right side of the shield. You might have noticed this on your Tundra but with your headlights shining on a vehicle ~100ft away the step creates roughly a 4ft difference in output which is too much and limits what would be useful light on the left side while driving.

The point is to keep light out of the eyes of oncoming traffic so say your headlights are aimed properly and the right side of your output is illuminating just under the side view mirrors of cars while driving which means your headlight aim is correct but "maximized" where you couldn't aim them much higher without occasionally blinding people. If this is the situation then the D2S 4.0 projects light 4ft lower on the left side and 4ft below the bottom of side view mirrors on most cars (let's use mid sized sedans as the norm) would mean you are not illuminating any of their vehicle and even not illuminating some of the road just before their vehicle. This is why on most of my D2S 4.0 retrofits I shave down the shield bit (I did a little on the Panamera build linked above) roughly removing 1/2 of the height and the end result is your D2S projectors will now be illuminating the wheels or lower fascia of that oncoming vehicle. An added bonus of this modification is when the shield is shaved down it allows more intense light of the "hotspot" to pass through which is very helpful for distance vision, it's a win-win.

I don't want to convolute this thread too much with my HID stuff so I will share a link instead of posting pics but you can see output pics of the "E55" (that has been modded with a clear lens), the D2S 4.0, and many other projectors here to get an idea of the output.
https://www.hidplanet.com/forums/for...l-beam-gallery

Evan