I was personally kind of surprised to see Royal Purple with such low ZDDP levels (especially at $10.99/quart). It may be that synthetics don't require as much due to the anti-wear properties of the oil, itself.
"When I'm in a slump, I comfort myself by saying if I believe in dinosaurs, then somewhere, they must be believing in me. And if they believe in me, then I can believe in me." - Mookie Wilson
