FieldEngineer

Oil lab analysis instrumentation looks at atomic elements. Silicon (Si) is a component of 'silica' (dust). As a former Cat guy with nearly 20 years then 22 more years with Cummins, neither manufacturer specifically states that the K&N air filter is not approved nor approved. Both engine comanies specify to the chassis builder that they select an air cleaner system that will provide a minimum overall efficiency rating of 99.7xx% minimum. K&N products have claimed that their maximum efficiency is 96%....that would be a complete failure in an air intake system. Caterpillar has stated in print that use of non-CAT recommended parts will not void the warranty neither do they cover the failure from use of such parts....it is up to that part's manufacturer to stand behind their product. (Paraphrased). Cummins says the same but not as plainly as Caterpillar. Gary Spires Retired Cummins Field Engineer

Maximum fuel economy is achieved by operating your engine at the RPM where the BSFC, Brake Specific Fuel Consumption, is logged at its lowest. The engine manufacturer has this data. Also, in response to some who said that operating at RPM below torque peak damages the engine; this is only true if the engine will not acclerate smoothly if you step on the pedal. When you take off from a stop, you are operating at less than torque peak RPM and you also know that the engine acclerates without straining. Where operating at below peak torque (lugging) occurs, the engine will not accelerate under load....this is damaging specifically to the connecting rod bearing (upper half). Your auto trans should be set up to prevent this from occuring by downshifting accordingly. Gary Spires Retired Cummins Field Service Engineer