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the fuel as a function of the height of the phase separation point (data from Reference 2). This chart will provide a close estimate to the percentage of ethanol in the tank. Our most recent review of Porsche sports car motor oils (Reference 3) summarized Porsche's currently approved motor oils and how they compared with the USA American Petroleum Institute (API) Classification system markings that appear on most motor oil containers sold here. The latest API oil classification change was announced this past fall for gasoline powered automobiles with the addition of new category of "SN" oils to the previous SL and SM categories that were the previously most advanced in 2008. Porsche has consistently recommended synthetic multi-viscosity oils for their sports cars with a second digit of 40 or 50 (such as 0W-40, 5W-40 or 15W-50) that relates to the viscosity at high oil temperatures. For the SL and SM designations of 40 or 50, the API classification system does not limit the quantity of Zinc and Phosphate anti-wear additives that can affect camshaft wear, so each oil producer has options. We will look forward to learning of any new options that develop in motor oil formulations during 2011. Motor Oil Initiatives 1. A. Caldwell, "The Return of Ethanol," Porsche Panorama, December, 2007. References 2. "Changes in Gasoline II," Downstream Alternatives, Inc., 1992. 3. A. Caldwell, "Motor Oil Update Revisited," Porsche Panorama, October, 2008. This year, it will be interesting to follow the Porsche's 2011 production vehicle developments in hybrids, such as the 918 Spyder hybrid along with the rumored new 991 sports car. January 2011 39