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      06-25-2014, 12:13 PM   #88
jphughan
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Drives: '16 Cayman GT4
Join Date: Mar 2011
Location: Austin, TX

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AHL2 mini-review

I got a chance to go out and experiment with AHL2 on both lit and unlit roads at both high and low speeds. Here's my preliminary verdict and a few notes:

First, only the driver's side lamp seems to behave noticeably differently with AHL2; the passenger side lamp is either unchanged or minimally changed, which seems consistent with the diagram in Post #1 here. I guess BMW is focusing just on keeping as much of the ROAD lit as possible (since the driver's side would have the oncoming traffic lanes), but I was a bit disappointed by that because I think it could be useful to improve the lighting of whatever is beside the road on the passenger side while driving at low speeds. Oh well.

Second, AHL2 is disabled while high beams are active. The lamps behave just like AHL1 in that scenario. Just fyi.

As for driving impressions, on lit roads at low speeds, if you toggle your headlight switch between the Auto and "regular" positions AND you're actively watching your driver side head lamp, you can definitely see the beam change just like in the video in Post #1 -- but it makes zero practical difference to your visibility. If you only ever drove in lit areas at night and I coded this to your car without telling you, you would probably never notice anything had changed. While toggling between the modes at high speeds (80 MPH), even while carefully watching the beam, I could only see the tiniest difference, which again is consistent with the Basic Light vs Motorway Light diagrams shown in Post #1.

On unlit roads, you can definitely see the driver side beam reorienting as you change your speed. It's definitely cool to watch, and you might notice it even if you weren't watching for it, but again it's not a major difference even at low speeds where AHL2 activates Town Light. I certainly don't think it's WORSE than before, but I'm having trouble thinking of a scenario in which this lighting setup would be meaningfully different from AHL1. I'm sure there are such situations, otherwise BMW wouldn't have invested the R&D to create this and made their cars' head lamps more complicated for no benefit, but I'm not sure what those situations might be.

So, bottom line: Yes, AHL2 is definitely cool to show off. But even when its adjustments are detectable, they may not be useful. And as the diagram in Post #1 indicates, from 30-70 MPH, AHL2 behaves just like AHL1 anyway, so if you don't have it, you're not missing out on a lot -- unlike the truly amazing no-dazzle high beams on the F series cars.
__________________
'16 Cayman GT4 (delivery pics, comparison to E92 M3 write-up)

Gone but not forgotten:
'11.75 M3 E92 Le Mans | Black Nov w/ Alum | 6MT (owned 5/2011 - 11/2015)

Last edited by jphughan; 06-25-2014 at 12:40 PM..