Metroplex,
I am basing my view on a chemistry paper by Exxon/Mobil chemists and until I see information to the contrary, that's my story and I stickin' to it:
The later information comes from papers and patents. The paper was the Feb. 2001 write-up in Lubrication Engineering, "High Stability Esters for Synthetic Lubricant Applications." The paper is mostly a discussion of the chemistry of various esters and especially the TME ester.
The paper's key subject area seems to be the enhanced thermal stability, the reduction of viscosity growth, and the need for longer drain intervals that this ester can provide.
There are seven Exxon/Mobil patents from the period 1995 to 1998 relating to these new esters.
Exxon/Mobil may have used Group III in their System-S, but from what I read, everything else is PAO/Esters developed from their years of research.
Do you have some technical papers that show differently?
[ April 01, 2003, 09:51 AM: Message edited by: MolaKule ]