Howdy fellow oilers I just picked up several cases of API "SF" oil at our local dollar store, (they are changing their prices and the old stuff was priced the old price - I couldn't resist). Obviously, this oil is cheaper than even the "Supertech" brand at Walmart, (current price in these parts $1.07). My question is really basic - what's so "bad" about this oil. I know the newer stuff has more additives, but if I understand what I read, less ZDDP. Is this correct? If that is the case, doesn't that kind of balance things out so to speak? I mean, we're not talking something ancient like "SB" or "SC." "SF" oil additive package isn't that long ago. Every automobile I have is old with the exception of my wife's automobile, so I don't mind putting el cheapo oil in everything but her car. I'm just wondering what the big difference is between "SF" and "SM".