http://www.lnengineering.com/oil.html Good page on engine oils. An excerpt: Sample Detergent non-synthetic oil: Castrol GTX 20w50 had .14% Zn and .12% P. Valvoline VR-1 Racing 20w50 had.13% Zn and .11% P. Sample Detergent synthetic oil: Mobil 1 15w50 had .14% Zn and P. Both SuperSyn and Extended Performance formulations tested identical. Amsoil, Penn-Grade, Royal Purple, and Redline synthetics all met the recommended levels. Sample Detergent non-synthetic mixed fleet oil: Delvac 1300 15w40 had .17% Zn and .14% P, no moly. I like to point out that a local big rig shop that maintains fleet vehicles uses and recommends Delvac 1300 over all other mixed fleet oils, including Delvac 1, which is the synthetic version of Delvac 1300. All other mixed fleet oils we tested had the recommended levels of zinc and phosphorus, but most did not have the moly typically found in other motor oils. Sample Detergent synthetic mixed fleet oil: Shell Rotella 5w40 had .16% Zn and .14% P. The reason for my choosing Shell's synthetic mixed fleet over any other is it's very high TBN of 10.77 which brings the cost of this oil per mile down significantly with it's extended drain capabilities.
Also a forum dedicated to oil testing, has analysis with additive content like zinc, phosphorous, moly, etc. for many oils: http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=11;t=000310
