Just last week I was reading a bunch of tech articles about motor oils.
Seems true "Full Synthetic" oils are really expensive.
The stuff you pull off the shelf at Wal-mart that claims to be Full Syn really isn't at all
They use "Synthetic" as a marketing term, there was a law suit about it.
but anyway, the stuff on the shelf that says Synthetic is really just super pure regular oil.
And they use more expensive additive packages to it.
There's like 5 grades of oil
I'll try to find the link for it so you can read it.
** found it
All About Motor Oil
Read that
"In the late 1990s, Castrol started selling an oil made from Group III base oil and called it SynTec Full Synthetic. Mobil sued Castrol, asserting that this oil was not synthetic, but simply a highly refined petroleum oil, and therefore it was false advertising to call it synthetic. In 1999, Mobil lost their lawsuit. It was decided that the word "synthetic" was a marketing term and referred to properties, not to production methods or ingredients. Castrol continues to make SynTec out of Group III base oils, that is highly purified mineral oil with most all of the cockroach bits removed."