Re: Synthetic oil
My engineering field wasn't motor oils, but I was interested since we had a lube blending and packaging plant on site. Additives came from somewhere else. The refinery just produced the base stocks. Somewhere else made the additives which can amount to 40% of total volume. Biggest advantage of PAO oils is low pour point(cold temperature when the oil won't pour anymore) meaning better in cold weather. Reduced friction, maybe a marketing claim. I figure with the cost of modern cars a few bucks more for an oil changel is money well spent.
My refinery actually made more industrial oils than motor oils. Interesting that the base stocks had to be distilled in a vacuum. Oil cracks when heated to more than 700F, so vacuum was applied when boiling range was over 700F which lube oils are.
Lube stocks are highly refined. The base stocks have the aromatics taken out by solvent extraction and the wax taken out by cold filtering. Dino crude oils already have the lube oils in them. The lube oils are produced by taking out the non lubes by processing.
Non PAO synthetics are made from crude oils not containing lubes. The lubes are produced by hydrocracking the base stocks.
Lube oils are branched chain paraffin hydrocarbons. Longer chain hydrocarbons would mean higher boiling point. Don't have a good reason for dino oils in the flathead!
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