Spart
Senior Member
Maybe if we're using this mat:That maybe is the best solution to keep engine temps down on a stock engine + maximum power + sustain best protection.
In reality - what range does a 5W-30 shear to when it shears out of range? And which end of that new range will it end up in?
How does this in any way support the hypothesis that 5W20 "sustains the best protection" all else being equal?
You're also ignoring a lot of key bits of info from that video, such as when Lake specifically points out that xW-20 oils that have sheared out of grade will (on average) cause increased wear, whereas xW-30 oils that have sheared out of grade do not see an increase in wear.
In fact, looking at that chart, it seems like xW-30 oils are actually the breaking point for shear stability being important for stable wear protection. Once you go below xW-30 to xW-20, it becomes critically important that the oil stay in grade. xW-30 and above, not important.
So let's revisit that chart you posted. It showed that 43.1% of 5W-30's will shear out of grade, where only 1.3% of 5W-20's will shear out of grade.
Sounds like a big W for 5W-20 until you combine those two facts and realize this means that 1.3% of 5W-20's will cause increased wear due to shearing out of grade, while 0% of 5W-30's will cause increased wear due to shearing out of grade. Then it becomes a W for 5W-20 if you put the facts together.
Further, if you look at the chart that you didn't post:
This is important because 0W-20 is the factory fill and cap recommendation for these cars, so it will be most people's point of reference. So now we're at 14.5% of 0W-20's causing increased wear due to shearing out of grade, whereas (again) 0% of 0W-30's will cause increased wear due to shearing out of grade.
So if you want the "best protection" - seek a 0W-30 or 5W-30 and worry not about whether your oil is shearing out of grade.