http://www.atvoutdoors.net/topic.asp?TOPIC_ID=4876
Have at it...
Its a good long writeup, but some of the information is a bit off base.quote:
Shortly after Mobil lost their lawsuit, most oil companies started reformulating their synthetic oils to use Group III base stocks. Most of the "synthetic oil" you can buy today is actually mostly made of this highly-distilled and purified dino-juice called Group III oil. Group III base oils cost about half as much as the synthetics. By using a blend of mostly Group III oils and a smaller amount of "true" synthetics, the oil companies can produce a product that has nearly the same properties as the "true" synthetics, and nearly the same cost as the Group III oil. Mobil-1 is now primarily made from Group III unconventional base oils. The much more expensive traditional synthetics are now available in their pure forms only in more expensive and harder to obtain oils.
Have at it...