I don't know if you have read through540 Rat's blog but the guy who writes it is a: I’m a working Professional Degreed Mechanical Engineer, and Mechanical Design Engineering is what I do for a living. A Mechanical Engineer is clearly the most qualified Engineer to test motor oil that was formulated by Chemical Engineers, for wear protection capability between mechanical components under load. He has lots of info on all the different kinds of oil and what he recommends. Here is the link it is a very long read and when he gets time he updates the info. His oil of choice is Quaker State and Quaker State® Euro Full Synthetic motor oil is Mercedes-Benz approved:229.3 229.5.
Here is the link: https://540ratblog.wordpress.com/
Here is the ranking for Quaker State and Pennzoil Platinum:1. 5W30 Quaker State “Full Synthetic” (abbreviated QSFS), dexos 1 Gen “2”, ILSAC GF-6A, API SP = 152,674 psi

NOTE: THIS MOTOR OIL HAS BEEN DISCONTINUED, AND WAS REPLACED BY A NEWER VERSION WITH GM dexos 1, Gen “3” certification. SEE BELOW FOR THE NEW OIL’S RANKING POSITION.

And that psi value sets a WHOPPING NEW ALL-TIME RECORD for motor oils that I have put through my Engineering Torture Test on motor oil. It was tested in Spring 2021.
This new 5W30 Quaker State “Full Synthetic” motor oil replaces the previous 5W30 Quaker State “Ultimate Durability” (abbreviated QSUD) synthetic.
zinc = 905
phos = 764
moly = 176
The psi value of this new oil, which came from testing it at the normal operating test temperature of 230*F, put it in the SPECTACULAR Wear Protection Category. However, I went on to also test this oil at a much higher temperature of 275*F. At that elevated temperature, most hotter and thinner oils typically experience a drop in Wear Protection Capability. But, even at that elevated temperature, this oil produced an extremely impressive 148,133 psi, which was only a small 3% drop in capability. And that value put this much hotter and thinner oil in the AMAZING Wear Protection Category.

I also tested this oil to find out its onset of thermal breakdown, which was 290*F.

This new oil was purchased at Walmart. And its truly amazing performance is further proof that Walmart is selling legitimate motor oil, even though their prices are extremely low compared to typical Auto Parts Stores.

Many of us who have been devoted users of the previous Quaker State “Ultimate Durability” motor oil, were concerned that Quaker State’s Corporate bean counters might get their hands on this new Quaker State “Full Synthetic” oil and cut costs that would ruin the oil. Fortunately, as it turned out, that did not happen. And in fact, now this latest new 5W30 Quaker State “Full Synthetic” motor oil, is BY FAR, the BEST PERFORMING motor oil that I have ever tested. This is absolute proof that Quaker State knows how to formulate motor oil.

This new “Full Synthetic” motor oil has set the bar so high, that it is the oil I will be using in my vehicles from stock to High Performance, from now on. And it is the motor oil that I will recommend to my Blog readers for most water-cooled, gasoline-powered engines, that can use 5W30. This is especially THE “go to” motor oil for traditional flat tappet engines to provide the utmost in protection against wiped cam lobes.

Never say never, but it is hard to imagine another motor oil ever producing numbers this amazing.

Here is a back-to-back comparison of the new 5W30 Quaker State “Full Synthetic” and the old 5W30 Quaker State “Ultimate Durability”.

NOTE: The Higher the psi value, the Better the wear protection capability. The Higher the onset of the thermal breakdown value, the Higher the oil temperature can reach before the oil begins to deteriorate due to heat.

QSFS at 230*F = 152,674 psi
QSFS at 275*F = 148,133 psi
QSFS onset of thermal breakdown = 290*F

*****
QSUD at 230*F = 133,125 psi
QSUD at 275*F = 115,764 psi
QSUD onset of thermal breakdown = 275*F

The only possible concern about this amazing new 5W30 Quaker State Full Synthetic motor oil, was that it might be “too good” for use in wet clutch motorcycles. But, motorcycle Owner feedback in July 2021, proved that this amazing new motor oil works just fine in wet clutch motorcycles, meaning there was no clutch slipping at all. Of course that applies to wet clutch motorcycles with clutches that are in good condition.

141. 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
zinc = TBD
phos = TBD
moly = TBD
This oil was tested in Spring 2016.