Originally Posted By: Hokiefyd
Originally Posted By: Le_bow_ski
Originally Posted By: Smokescreen
Originally Posted By: Le_bow_ski
... For the beam pattern to change the headlight would have to be damaged, which is very unlikely given the minor 10 watt increase in power requirement (65w vs 55w).
Not true. Sometimes a headlamp assembly can be overcome by too many lumens, not always visible just by casual viewing. Too much light affects the way the beam is projected and causes internal reflections with unwanted side effects such as partial halos ranging from 4 to 10 feet above the lamp...
Sorry, I'm not seeing the physics of how more light output effects the way photons travel within a headlight. Now, on the other hand, if you were to say a higher output bulb more clearly reveals flaws in the manufacture or design of the headlight, well that's another story. Or, if the bulb is of a different configuration, yes, of course I agree with you. But the raw quantity of light has no impact on the reflected or projected pattern. That's basic physics.
A light source that is significantly more powerful than what was intended can increase glare in certain measurement points, to where the lamp is now out of compliance with regulations. Additionally, even though the bulb may be to the same specification (H11, for example), filament placement is critical to headlamp performance, and higher quality bulbs usually have more precise beam focus because the filament is smaller and positioned in the bulb to a tighter tolerance than what is minimally required. So some aspects of the beam pattern can "change", though it's usually not to a great degree.
I saw this first-hand with HB2 bulbs in our Honda CR-V. With the standard Philips LL bulbs, there was a fairly even distribution of light within the beam, with no particularly bright or dark areas. With up-rated Philips Xtreme Power bulbs, one would think that everything within the beam pattern would be made brighter by X multiple. That didn't happen. Because the beam focus of with the XP bulbs is much better, there is an intense hotspot in the center of the beam, straight down the road. Other areas of the beam pattern did become brighter, but the relative change was not constant throughout.
It is possible for areas of light outside the intended beam pattern to increase to annoying or dangerous levels. We're talking about almost doubling the source lumens here...1100 lumens for an H11 and 2100 lumens for an H9. Sometimes bulb base reflections and other areas of controlled glare that are acceptable with an H11 become unacceptable with an H9.
I think both of you may be talking around the same point. It is true that the beam pattern will not change, in the sense that the general and shape of the cutoff and relative distribution of light within the beam pattern should remain the same, at least to some degree. It is true that areas of controlled glare or unwanted reflections that are acceptable or are within compliance limits with an H11 could be made unacceptable or taken outside of compliance limits with an H9.
Agree you guys are talking around the same point. I think the big difference is if the application has halogen projectors vs. typical refelctors. I did some research a while ago on the Candlepower Forums where there is a mod who has significant knowledge of what you are talking about. Essentially he said that projectors are good to go H11 to H9 but refelctors are not. The exact example was the 4th Gen 4Runner vs. the new ones. The 4th Gens have halogen projectors and can handle the increase from a H9 without glare, but new ones cannot because they have the non-projector shields.
To the OP, you should be ok with the H9s. I got mine from candlepower.