Found this on Nico... Actual 'proper' filter testing of standard and aftermarket air filters. It's for the GM Duramax turbo diesel engine, but close enough And this isn't some dodgy vacuum cleaner test, it uses a proper machine and is tested to ISO 5011. Independant test and not by some magazine with hidden agendas or by manufacturers with not so hidden agendas Clicky If you can't be bothered reading it, the standard OEM filter takes longer to clog, filters far more effectively but has a higher initial pressure drop. What is most interesting is the huge pressure drop as soon as the aftermarket filters start to get dirty compared to the stock one...
hmm allays suspected the whole k & N oil thing was bullshit looks like your probably better off with a dry no name pod filter
