Quote:
Originally Posted by Bror Jace
And no UOA I've ever seen is able to measure the coefficient of friction of oils. I've seen some manufacturer testing (I think it was from Red Line) and I was aghast at the drop across the board among all brands ... and the oils were not in use all that long.
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Viscosity is a measure of fluid resistance, which can be thought of as friction
In any case (as internal resistance isn't what you're talking about
), friction coefficients are not the metric used (at least in the report's I've received) to determine when a oil starts to become abrasive, actually knowing these values would be purely academic.
Really, I don't see how one would measure the friction coefficient - that's going to be dependent on the individual parts (materials, surface condition, etc.) and their load conditions on top of the state of the oil. I guess one could make a standardized test, but those figures would again, be purely academic and, in this case, not directly applicable (compared to metrics such as TBN, insolubles, elemental makeup, etc.).