Quote:

Pacnorth...

can you please elaborate on the difference between the base oil differences between Group 4 and Group 3?

From my research and talking to a good friend who is a surfactant (the slippery stuff in oils and soaps) chemist....I've always contended that since all Synthetics are Petroleum based, the term 'Synthetic' (defined as derived from something other that petroleum stocks...ie, wood or other derived surfactants) was a bit of an advertising misnomer.....I look at Synthetics as being more like "cherry-picked" or cultivated molecules that have uniform desired characteristics....chosen within a much more narrow range than "off the shelf" oils.

The Germans had very little oil reserves during WW2....their surfactant chemists did develop "true" sythetic (i.e., not petroleum based) oils based from wood and other plant forms that they used to supplement their limited oil reserves...this is where the term originated but it had been overused in modern years.

In simple terms...Traditional motor oils are made up of a more random batch of "good" and "not so good" (but still acceptable) molecules, in use it's really the 'bad' ones that break-down first which in turn dilutes the entire sump full of oil....synthetics are 'the chosen' molecules verified through testing to hold up longer so they tend to last longer under more extreme conditions....but they are not really "synthetic" in the true sense of the word.




Group III origin: Refined from crude oil. Chemically REARRANGED through hydrocracking and Catalytic Dewaxing.

Group IV origin: Chemically ENGINEERED from pure chemicals rather than refined from crude oil.

That’s the difference. One is refined, and one is not.

The thing people get caught on is that Polyalphaolefins (PAOs) can have some basis in crude oil. For example, the colorless gas, Ethylene, is a chemical building block of PAO based lubricants. The chemical ethylene can be derived from many sources the common ones being crude oil and natural gas. It could also be derived from coal tar pitch but not as common.

So while a good Group III motor oil will have good molecular uniformity, it will not match the molecular uniformity of a top tier Group IV (PAO) motor oil.

The base stock debate today is for the most part irrelevant as the additives that are blended into modern day motor oils have more potent friction reducing abilities than the base stock in its own right.

Quite simply, this is why some motor oils cost more than others; chemical engineering and the blending of costly additives.

CompSyn