Slickdiesel sets the standard for lubrication of diesel fuel injection systems. The components of diesel fuel-injection systems are lubricated by diesel fuel. Without proper lubrication, fuel injectors and pumps are subjected to increased wear rates and premature failure.
High Frequency Reciprocating Rig or HFRR is the ASTM standard for evaluating the lubricity of diesel fuels. The test measures the lubricity, which is the ability of a fluid to effect friction and wear between surfaces in relative motion under load. The test was developed in conjunction with the transition to Ultra Low Sulfur Diesel (ULSD) fuel, because the dramatic reduction in sulfur negatively impacted the lubricity of the fuel. The results of the test are recorded as measurement of Wear Scar Diameter or WSD. The larger the WSD, the less lubrication qualities of the fuel. The maximum WSD permitted by ASTM D975 is 520 microns. The Engine Manufacturers Association (EMA) recommends a 460 micron WSD.