03-06-2014, 11:49 AM
Unless you have characterized the stock air filter with a manometer, you really can't do more than speculate as to the restriction. This doesn't require costly equipment.
FWIW, Cummins once had a note on their European web page indicating NOT to use KnN filters due to poor filtering performance. While they are not EXACTLY the same, OEMs used to use oil wetted metal gauze for their air filters. A GM powertrain engineer told me that poor air filtering was one of the main reasons why 1950s engines had such short engine life. Caveat emptor.
FWIW, Cummins once had a note on their European web page indicating NOT to use KnN filters due to poor filtering performance. While they are not EXACTLY the same, OEMs used to use oil wetted metal gauze for their air filters. A GM powertrain engineer told me that poor air filtering was one of the main reasons why 1950s engines had such short engine life. Caveat emptor.