What makes a good oil good?

[SSDude]

After seeing good UOAs with Schaeffer's Supreme 7000, a blend and GC posted on this board, I do not know what makes an oil perform well. On the one hand, Schaeffer's has a great additive package and outperforms most synthetics. This seems to vaidate the argument made by Bob and others that it is the additive package that counts.

On the other hand, UOAs with GC have been outstanding. I have never seen a bad UOA with GC. GC appears to have a normal additive package. However, on Castrol's website it says that GC (Castrol SLX) creats low wear at start up. This makes me believe that it has a high ester content that makes the oil cling to metal thereby reducing wear. In other words, its GC's base stock that reduces wear.

What makes a good oil? A good additive package? A good basestock? Both?

 

[GregH]

A paper on the Chevron Website, and I forget where it was gave a great explanation of what goes into great oils. From what I have learned here it was very accurate. I am sure if not we will hear one of the experts chime in.
A great oil starts with a great base oil or oils. They need to be made with very small or no amounts of things like sulfur and nitrogen. Impurities like these hasten the oxidation process, etc. Poor base oil can be helped by additives to a point. At some level the additives become too expensive and still only help to a point.
Great oils, using great base oils, require fewer additives and last longer just because they are more stable to start with. Or if more additives are used,with a great oil, then that oil can be taken to a higher level of service than an oil with average base oils
So I think the answer is simple. As in most things that are manmade, oil is a sum of its parts. Great=Great and Average=average.
Just my thoughts
Gregh