Originally Posted By: glennc
JAG, what exact truth are you referring to here?
That oil blending is complex, that there are many variables involved and many requirements to be met, that are all sorts of compromises and give-and-take decisions to be made, that any oil needs to be a blend of more than one base stock type to function effectively, that no one base stock type has ideal characteristics if it were to be used as a finished motor oil?
Yes, that's it.
Originally Posted By: glennc
Let's just take them all as a given, since frankly those things are probably known and let's even say reasonably well understood to most of us here, and address the fundamental question being asked: if you have a choice between a primarily grp IV oil and a primarily ester (POE, for example) oil, with all other factors equal - or, more precisely, with all other factors having been equally well optimized for the chosen blend of base stocks - what oil will give you the highest performance capabilities overall?
Of those two choices, my opinion is that the primarily PAO based motor oil is overall best. The biggest reason is because I think PAO deals better with moisture-rich blowby than POE does (hydrolytic stability).
Originally Posted By: glennc
Do you really believe the predominantly-PAO blenders are creating the best possible oils regardless of cost? What is the possibility in your opinion that at least some of the ester-based oils are better products overall? Is the margin of error on your opinion too great to make a judgement either way? Is the application variability greater than the product performance variability? I'm curious what you think.
I think that the predominantly PAO based oils could be improved if cost became no object.
I'm sure that some ester-based oils are better overall than some PAO-based oils. IMO, an example of a likely-to-beaten PAO-based oil is Lubromoly 0W-40. Its response to ~320F temps in the presence of a penny was to dissolve a significant amount of copper while some other synthetics I tested did not dissolve such large amounts of copper even when the test lasted much longer.
Check out this thread about alkylated napthalene, especially the link in the first post.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=787833&fpart=1