Em relaçao a eficiencia dos varios filtros vou meter aqui um quadro comparativo retirado de um site feito por uma pessoa que trabalha nessa area...
........................................Standard.. ...........K&N..................Jetex...............Green...... ......Pipercross
Type:.................................Paper....... ...Oiled Fabric......Oiled Fabric.....Oiled Fabric.....Oiled Foam
No. of pleats:......................89................... ..22.......................25..................... .34.....................n/a
Media area m2:................0.87..................0.09..... ...............0.06..................0.08......... ..........0.04
Face velocity m/min:.........8.0...................75.8........... .......107.2.................86.7................. .194.4
Initial restriction kpa:........2.91...................2.51........... ........2.46..................2.48................ ....2.7
Dust capacity g:................88.7..................51.2...... .............26.2..................22.1........... .......155.4
Initial efficiency %:.............99.2................90.77.......... .......51.84................93.91................. 61.29
Final efficiency %:..............99.5...............95.86.......... ........55.35................94.31................ .39.59
This test was done on a Ford Focus air box with after market panel filters fitted.
The Japanese brands don't make any for this vehicle, but it show the typical characteristics
for the filter type. I would expect Blitz mesh to be as pipercross but with the lowest dust
capacity due to no oil and very thin media.
Notice the face velocity, High velocitys can suck dirt off of the element
Also note the differance in restriction. Not much in it concidering the down sides.