Originally Posted By: roushstage2
Since we are on the subject of lots of ZDDP here, what exactly do you want high levels for? I have seen bits and pieces of information on ZDDP for flat-tappet engines, but what exactly is it's purpose (I have seen it is really only good to have high levels on the flat-tappet engines)?
ZDDP is a sacrificial AW agent. It also benefit other areas of the engine as well. Bearings and cyl walls IIRC. It forms a surface like a whisker, and gives some added protection.
AD