I downloaded SAE 981444 about half hour ago and read it. This paper is entitled "Advanced Synthetic Passenger Vehicle Engine Oils for Extended Oil Drain Performance." I know it has been discussed on this forum before, especially for the "Aunt Minne" test, which was part of the many test results outlined in this paper. For what it's worth, here are my observations from a cursory first read:
- 2. While all the Mobil synthetics tested showed virtually NO viscosity loss due to mechanical shearing (test CEC-L-36-A-90), the 0w30 and 0w40 OUTPERFORMED the 5w30 and 10w30, with the 0w30 having an almost immeasurable loss in viscosity of <1%.
- 3. In the double length Sequence IIIE test, the 0w30 and 0w40 oils were outstanding, showing only a 28% increase in viscosity for the 0w30, while the 0w40 viscosity actually DROPPED 15% after 128 hours. Even at 256 hours (four times the normal length of the test), the 0w40 viscosity had only increased 17%. (For reference, the Sequence IIIE test permits up to a 375% increase in viscosity after 64 hours for an oil to "pass.")
- 4. Using ASTM D4684, it was clearly shown that synthetic 10w30 will out flow a conventional 5w30 from -25*c to -35*c.
- 5. The synthetic 5w30 used in the Aunt Minnie test had a particularly robust additive package with a virgin TBN of 11.8 and a sulfated ash of 1.3%. I'm not so sure how well that correlates to the Mobil 1 5w30 you can buy OTC today, but I'd be willing to bet 5w30 SuperSyn doesn't have virgin numbers this high. Nevertheless, the results of the Aunt Minnie test are nothing less than remarkable, IMO. It clearly shows that with a good PAO synthetic, once a year oil changes for short trip drivers are perfectly safe.