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Old 05-04-2020, 05:39 PM   #494 (permalink)
Cyborg ECU
California98Civic's Avatar
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,097

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,310
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Light metering test results

Well the windshield tint works. It lets most light in (and it seems within the Cali legal limit in full sun). And it is definitely cooler on my hand and especially on the dash. At this hour on a full sun day like today my dash is too hot to hold my hand on for more than a short second. I can do it indefinitely now. The dash is more like "very warm" than really hot. That is the point of the tint. Here are my measurements of the light transmission. What think you?

Three light meter tests (no bearing on heat rejection)

1) Tint on tint difference (test done early afternoon)
Rear passenger window with one layer metalized dark, high quality heat rejecting commerical car tint.
Full sun: 59,300 LUX
Tint: 10,300 (83% light reduction)
Rear driver side window with both tint layers
Full sun: 59,300 LUX
Tint on tint: 6,100 (90% versus direct sun, 41% versus one-layer)
2) Windshield test (overcast cloudy sky 8:15 a.m.)
Overcast open air: 10,500 LUX
Windshield without tint: 6400 LUX
With tint: 4200 LUX (35% reduction over OEM, 60% reduction over direct sun)
3) Windshield test (full sun midday, cloudless blue sky)
Open air: 59,396 LUX (steady reading)
OEM glass alone: 59,396 LUX (steady reading)
Tint: 42,000 LUX (29% reduction). But this reading fluctuated a lot over minutes and ranged from lows of 40,000 LUX to a fairly steady high of about 49,000 LUX.
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.

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