[madmaxx]

Patrickt is dead on, in fact over 1900 ppm from what I read causes bearing corrosion issues. Does anyone know the rate of consumption, 100 ppm every xxxx miles.

Originally Posted by patrickt

All of those oils are just fine for our cars including solid, flat tappet cams. Once you get over around 1200ppm it's no longer a case of protection, in and of itself, but rather how long that protection will last (because the additives are consumed). We all change our oil out long before the additives are used up, so that's not really a big deal. But to answer your question, the opening post in this thread lists Brad Penn as coming in at 1500ppm, but that doesn't mean it protects better. It's like vitamins, once you have enough, you have enough; taking more doesn't help you (and sometimes can hurt). And yes, there is a point of diminishing return for ZDDP as well. I have an SAE article where tests done on solid flat tappet cams and ZDDP back in the 1970's showed that once you crested about 1900ppm wear began to increase.