[HarryD]

Originally Posted by tomeric914

FWIW The Petroleum Quality Institute of America

Most if not all of the passenger car motor oils tested have less than the 1200 ppm Zn required. Most of the HD diesel oils fall around 1,200 ppm. What's the big deal about Brad Penn?

Rotella T Triple (1,098 ppm Zn) Petroleum Quality Institute of America

Brad Penn "Diesel" (1,148 ppm Zn) Petroleum Quality Institute of America

Chevron DELO (1,490 ppm Zn) Petroleum Quality Institute of America

In a nutshell. since car makers started using roller tappets to actuate the valves, the high levels of ZDDP required for flat tappets is no longer needed. The lower ZDDP helps to extend the life of catalysts which the EPA finds to be desirable. As a result, the SM/SN etc oils have lowered the ZDDP requirements. Hence most consumer oils are now below the 1200 ppm levels typically needed.

The Brad Penn we are interested in is the 20W-50 version.

I hope this clears it up for you.