I have something to add. Most companys boast their
oil in advertisments, that's marketing. Most sanctioning race programs will "bid" persay, for that companys
oil use for advertising. It's all about that mighty ole dollar.
Oil is oil, it's the aditives that vary between those companys. Oil, really does not break down, but, get dirty, the additives are what breaks down & have to be replenished. The "name factor" determens the price. I get my oil from "Parts Plus", their name on the bottle, it's like $0.87 each. Who's oil is it ? VALVOLINE. In our sprint car, we've run their cheap oil for years with no problems at all. Each winter during the rebuild, you can still see the cross hatching in the cylinders, no build-up of sludge ect...very clean. The most critical aspect of keeping an engine in top condition by way of ware is, CHANGE IT OFTEN ! Don't go by the, "every 3,000 miles or 3 months", it depends on how you drive it & the weather conditions. Who's oil did I see "world of outlaws, team "Quaker State" Steve Kinsers crew using ???
well........it was not Quaker State. Their are only a handful of oil refineries with 10 times that amount of brands on the shelf. Do you really think that all of the brands you can buy refine their own oil ? Does Pep Boys, Advance Auto or........Shopko ? ect....
In twenty years or so of building & maintaning my own race engines or our daily drivers, have I ever had a oil related problem. I know nothing.....about the synthetics, do they work, good question, will an engine have a longer life, don't know ? I've have my daily drivers last well over 250,000 miles untill their death, not to engine lube problems but, the car it's self has had it's better days. I think what it comes down to is, buy a quality filters, (oil & air) keep the engine full of oil at all times, change it often & choose the viscosity which conditions the engine will be run in. I'm not a pro-builder or a chemical scientist, just a car guy giving his two cents.
Thanks,