
Originally Posted by
rick130
Bingo.
High Si in particular will show with a K&N in dusty conditions, as well as elevated Pb, Al and Fe.
Silicon is used in some/most oils as an anti-foaming agent, but it's noticeable on a UOA when it's dust ingestion.
One of the South Africans posted some really good pics probably a decade ago on one of the now defunct UK boards of a 300Tdi with 80,000km of K&N use in predominantly dirt road conditions.
Every bore was totally stuffed, required a maximum re-bore. (and it wasn't a case of soft bores)
isuzurover also recounted the story of an F1 engine manufacturer that used K&N's until the first race in the middle east where they dusted multiple engines from the constant sand blowing across the circuit.
IIRC air flow and face velocities were pretty high, (naturally) but it's a pretty good illustration of what can happen.
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