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The ASTM Sequence VIB is the new fuel economy standard for ILSAC GF-3. The new test pushes the bounds of current engine oil technology. With concerns over Corporate Average Fuel Economy (CAFE) targets, the auto manufacturers have been strong advocates of the Sequence VIB. This paper describes findings of some of fuel economy studies for GF-3. The Sequence VIB is a significant step relative to the past Sequence VIA test in requirements for friction control. Stage-by-stage analysis indicates a shift to a higher degree of “mixed” lubrication response in the Sequence VIB relative to the Sequence VIA, 35 % versus 11 %, making both optimized friction modification and viscosity control necessary for obtaining high levels of fuel economy for GF-3. Viscometric contributions are controlled by both the (high temperature - high temperature) HTHS and basestock viscosity of the oil. Minimizing these viscometric measurements leads to improved fuel economy.

Two current motor oil trends are lower oil volatility and extended oil drain intervals. The reductions in oil consumption accompanying decreased oil volatility provide possible improved exhaust emissions and reduced servicing and maintenance. Longer drain intervals allow reduced frequency of required vehicle service, providing a lower cost of ownership to the consumer. Given these concurrent trends, this study investigates the possible impacts of volatility in extended drain applications. Four 5W30 oils having volatilities ranging from 5.3 to 21.5 wt % evaporative loss by ASTM 5800 were tested in extended drain New York City taxi service. The drain intervals were 10,000 miles and 20,000 miles, and the test duration was 100,000 miles. The additive packages were of API SJ or SJ+ quality. Oil performance was found to be significantly impacted by volatility. A primary effect of volatility was the degree of oil consumption and resultant replenishment with fresh oil.