Quote:
Originally Posted by Amadeus
Not to flame here - oil is a hotly contested subject but I made a couple of charts below with some of the popular and recommended oils from this thread. The first is sorted by Viscosity Index with the highest number being best. The second chart is sorted by KV @ 40*C which is cold starting viscosity. All are within a point at 100*C operating temp. Eneos Sustina clearly is tops in both charts but at a premium price. Idemitsu SN (Subaru oil?) is relatively inexpensive and has very good numbers. I couldn't get any numbers for the Toyota SN except Viscosity Index and the one UOA (used oil analysis) I saw on BITOG (bobistheoilguy.com) showed a marked reduction in Moly from the SM formula. The bottom five share similar numbers. So here is my question to some of the more knowledgeable forum members:
If we are looking at oils that have similar properties (say the bottom 5) what criteria should we be using to distinguish between them. Do we look at the base oil, TBN, Moly and other additives, UOA's on forums? How are you choosing your oil? Motul 8100 is recommended here but based on the chart Amsoil looks better. If there is a list of criteria after VI what would the order of that list be?
Currently I'm running Toyota SN because that's what the dealer installed and because I hadn't made up my mind until today what to switch to. I will probably run a UOA for sh*ts and giggles on the ToyoSN just to see.
I'm not trying to start a sh*t slinging war just genuinely interested in how people came to their decision on oil.... 
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40C isn't cold starting viscosity and is 104F. The cold cranking abilities of 0W-x oil is measured at -35C.
http://www.pqiamerica.com/coldcrank.htm
If you want to see the actual viscosity at 0C/32F, plug the numbers into a viscosity graph/calculator.
http://www.widman.biz/English/Calculators/Graph.html
I wouldn't pick any one number when it comes to choosing an oil. It depends on your particular application and even then it may not matter as much. I think a lot of people pick their favorite brand since there isn't much data from these cars. Most of the uoa's are still during the break-in period.
-Dennis