Originally Posted by DougR

I extracted a summary of RAT's oil testing from his lengthy and verbose report. He measured wear protection in psi, however he didn't measure Moly, Mag, Zinc and Phos content, so I included Moly and Mag content from PQIA. Higher psi values equate to better wear protection. Over 120,000 psi is fantastic wear protection. 105,000 to 120,000 psi is incredible wear protection. 90,000 to 105,000 psi is outstanding. One may argue that laboratory measurement of wear protection does not simulate how an actual engine wears.

RAT tested Amsoil oils Fall, 2017.

0W20 Amsoil Signature Series, no API designation, synthetic 134,860 psi at 230F. Onset of Thermal Breakdown not specified. Moly and Mag not measured for 0W20. Values for 5W30 are Moly 153 ppm and Mag 19 ppm.

RAT tested the following oils Spring, 2016. These are listed from highest to lowest wear protection (psi).

1. 0W20 Quaker State Ultimate Durability, API SN, synthetic (gold bottle) 124,393 psi at 230F (106,163 psi at 275F). Onset of Thermal Breakdown 270F. Moly 249 ppm. Mag 9 ppm.

2. 0W20 Toyota Motor Oil, API SN, synthetic 101,460 psi at 230F. Onset of Thermal Breakdown 255F. Moly 787 ppm. Mag 674 ppm.

3. 0W20 Mobil 1 Extended Performance, API SN, dexos 1 approved, synthetic 100,229 psi at 230F. Onset of Thermal Breakdown 265F. Moly 85 ppm. Mag 777 ppm.

4. 0W20 Pennzoil Platinum, Pure Plus Technology, made from Natural Gas, API SN, synthetic (silver bottle with blue vertical stripe on the label) 92,504 psi at 230F. Onset of Thermal Breakdown 275F. Moly 57 ppm. Mag 8 ppm.

Toyota Motor Oil has the highest combined Moly and Mag content and the lowest temperature at the onset of thermal breakdown.