Measure the inlet air restriction. Install the vacuum gauge, Part No. ST-434, or a manometer in the intake air piping.
NOTE: The gauge adapter must be installed at a 90 degree angle to the air flow in a straight section of pipe at a minimum of one pipe diameter before the turbocharger.
Operate the engine at maximum horsepower RPM and Advertised Horsepower.
Observe the reading on the gauge or manometer.
NOTE: Restriction must not exceed 635 mm H20 [25 inches H20].
