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More air DOESN'T mean more dirt. That's just not true. Some aftermarket air filters will let more air through AND filter dirt better. Why don't manufacturers put them in straight of the assembly line? Costs. An aftermarket air filter can easily be 10 times more expensive than stock.



More air = more dirt was proved when I had my oil tested on a Ford Expedition I owned.
I was running with a K&N and the dirt level in the oil was at 16.It should have been around 6.It was 8 with a paper element.
I stick with OEM from now on.