And for adrenaline. Thicker is not better either.
Run a super thick oil on the track and congratulations. You now have less oil flowing over the surface of your bearings at the same oil pressure as an oil that is thinner and flows more freely over the surface.
Even in race conditions. Running a thinner is will provide better results. More hp. Easier spinning assembly. Low temps due to decreased friction and better bearing life because the continual flow keeps the additives that get distributed to the bearing surface flowing in and out to place new molecules of zddp. Moly. Or whateverelse your oil has in it as anti wear agents, on the surface.
You complained before about having oil like water at the end of arace. Well if you used a good synthetic oil (group iii, ester or pao) you wouldn't have that issue because synthetics all but eliminate the thinning that occurs with mineral based oils (dino oil. Whatever you want to call it).
You can sit here and preach all day about ehatever you want. But in the end. Using the proper weight oil for the right application is what its about.
Too thin means not enough pressure and not enough oil flow, only a certain amount of oil can be spread out onto the surface of the bearings. And contrary to what you said about 2jz having similar clearances to another engine... true if it was a brand new motor... but 2jz and everything else wear over time. And if the wear is too great the available room for oil to enter bearings becomes larger. Meaning less pressure with the same oil thickness.
So having to choose the right thickness comes at testing for your own car to find out what grade oil it takes to keep the car satisfied. Without going too high (like his 20 50 grade) which will obviously give you high pressures. But at the high price of restricted flow and reaching a maximum circulation of oil at a far lower rpm. Which in cars like these that rev high whenracing. Having good oil flow at high rpms is essential.
In the end having something in your car that has a weight of 0w20 or 5w30 is all up to you. But I woul never run something that has more than 10w as the startip weight. You are only asking for trouble at that point because having something even as thin as 5w will cause startip wear. Which will cause more grief than 6 hours of pure driving on that 1 startup.
After you can choose the right weight for the car based on your conditions (where you live. What you use it for. How long you drive it every day. What temps it reaches. How worn is the engine) then you can find out which manufacturer provides you with the right oil.
Lots of oils are good. Some are better. Some are not so good.
And example is an oil meant for racing . Pure racing oils that actual race teams use have little to no detergents in them because they are meant to be changed every race. Run that in your normal car for a year and your looking at a lot of buildup.
Off the shelf motor oils will have low levels of zddp and other antiwear agents as a result of the epa wanting to keep catalytic converters from going to hell from the additives in the oil. As a result its hard to buy an oil with higher levels of antiwear agents in them from the local store.
And these antiwear agents in the additives will provide far more bearing protection and lubrication than trying to go nuts over buying a super thick oil with the mentality that thicker means more slick.
I could write more but there's too much info out there for everyone to read and learn.
Cliffs. Adrenaline needs to read up and stop using 20w50 because its "better"