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      06-22-2012, 10:18 AM   #81
Bimmer-Bob
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Drives: 2010 128i
Join Date: Feb 2010
Location: Anacortes, WA

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There is a permanent filter in the air box that contains a black powder. It's function is to absorb evaporating hydrocarbon vapors and thus lower emissions. Given it's appearance and function, I think it's very, very safe to presume that the substance is activated charcoal. I personally don't believe that there is any performance to be gained from removing it.
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