Many people confuse the H9 and H11 led bulbs to be the same bulb. Now although they are similar, they actually have different features and major changes when it comes to their performance. Which is why today, we are doing an H9 vs H11 comparison.
‘What’s the difference between H9 and H11 LED Bulbs’ – you are asking yourself.
Well, at first glance, everything from the trim tab to the connector of both H9 and H11 bulbs looks similar. However, if you look more carefully – you will notice that the H9 bulb has a tab at the top of the female side which is not present in the H11 led headlight bulb. Also, the top lugs on each bulb are identical in the H9. This is not the case in the H11 led bulb, where they are asymmetrical and opposite.
The performance of the H11 led bulb definitely overcomes the  H9 headlight power – which is why the H11 comes as a great re-aim on your headlights.
As we continue with our H9 vs H11 headlight comparison, we’d like to state that for the fog light, the H9 bulb fits better with a slight modification. The whole ‘science’ behind all this is the performance in lumens. An H9 headlight bulb modification can give you 2100 lumens than the standard 1450 lumens, with only a 10-watt and 2-amp increase. The benefit from all this, though, will be a much brighter light than stock.
If you see more carefully, you will see that both of them consist of a base that can be trimmed. The portion of this base should be trimmed measures around 3mm from the left side of the top lug in order to allow the headlight bulb to fit in the top light housing. Also, the bulbs should be maintained with debris which must be wiped down with a soft towel and 91% Isopropyl in order to clean off the debris.
Update: HID Headlights are slowly being replaced by LED technology. One of the better LED headlight kits we’ve come across is the XenonPro. They make a great kit, and they’re a solid, reputable company.  Check them out!
In case you want to use a regular H9 as your H11, you can always remove the tab top on the female side by using a small sharp chisel and a rubber mallet.
At last, we can come to the conclusion that the H9 bulb has a harder driven filament, no glare cap, higher wattage but also a shorter life. However, it remains a significantly higher output. Therefore, it is a significant upgrade you may consider.