Like I've said...excess zinc is almost as bad as too little. I'd have to think hard about it but my memory is that VR-1 was the most HP eating oil I tested. Could be that a Pennzoil was as bad or close.
Synthetic (I should say group IV and V synthetic) base stocks will do everything a standard mineral oil and much more. Group III synthetic base stocks are not really synthetic, but somehow a bunch of dumbass goofballs in long black robes decided that group III base stock are synthetic. That's why Gus running alcohol based fuels can switch to a group III base oil and not have issues. You run alcohol on group IV and V base stocks and you can have issues.
Just as important as base stock and zinc percentages is the detergent and dispersant packages, the EP package (as I write that I may be fudging calling it EP for engine oil but I'm not feeling good at the moment) and even the viscosity index Improvers are important.
That makes an engine oil, engine oil. Buying an oil based on its ppm of ZDDP is limiting at best. Doesn't mean you stuff will expire in Hollywood fashion. Just means you are probably leaving a bit on the table.
