Small dust grains cause a higher intensity of increase in the flow resistance of the fibrous filter bed, which, due to the established value of the permissible resistance, results in a shorter period of operation of the air filter and the vehicle. At the same time, the mass of dust per unit of filtration area takes on smaller values. Such a phenomenon occurs in the two-stage “multicyclone-baffle filter” engine inlet air filtration system. The main objective of this study was to experimentally determine the mass of dust retained per unit of filtration area (dust absorption coefficient km) of the PowerCore filter bed operating under two-stage filtration conditions, which cannot be found in the available literature. The original methodology and conditions for determining the dust absorption coefficient km of a PowerCore filter bed operating under two-stage filtration conditions are presented. Tests were carried out on the characteristics of filtration efficiency and accuracy, as well as on the flow resistance of a filtration unit consisting of a single cyclone and a PowerCore test filter with an appropriately selected surface area of filter material. During the tests, conditions corresponding to the actual conditions of vehicle use and air filter operation were maintained, including filtration speed and the dust concentration in the air. The experimentally determined dust absorption coefficient of the PowerCore research filters operating in a two-stage filtration system took on values in the range of km = 199−219 g/m2. The dust absorption coefficient km of the PowerCore research filter operating under single-stage filtration conditions reached a value of km = 434 g/m2, which is twice as high. Prediction of the mileage of a car equipped with a single-stage and two-stage “multi-cyclone-partition” filtration system was carried out, showing the usefulness of the experimentally determined dust absorption coefficients km.