I bought a
Donaldson TopSpin to use with the XM1027 project (CUCV knock-off). I'm putting it before a
Donaldson PowerCore two-stage air filter using a custom snorkel duct. The
Donaldson PSD series is rated for "heavy dust" filter is what Oshkosh is using on the new MRAPs and L-ATV prototypes, it has several rows of cyclonic particle separators (think Dyson bag-less vacuum cleaner), right before a ridiculously high capacity and flow air filter (dry-type, not cleanable) with an internal backup filter. There is an outlet for the pre-cleaner which can either dump the separated dust to ground, or be used with an exhaust aspirator to suck it out of the air filter housing and blow it out your exhaust pipe (like heavy construction vehicles do in very dusty work-sites).
They aren't that expensive either, I paid $300 for both parts, filters for the PSD10 I bought are $66 for the primary, $35 for the safety filter. Recommendation is to change the primary filter every second oil change, and the safety filter every third primary filter change - with a
"FilterMinder" type device you can stretch the filter interval to when it's needed, not when it's easier to remember to check.
[EDIT:] If you're really worried about dirt/dust, the air filters found on most quarry trucks are also Donaldson two-stage air filters:
Donaldson SSG [/EDIT]
[EDIT 2:] YouTube video on how (and how well) the spinning pre-cleaners work:
[/EDIT 2]