Oil weight influenced by epa mileage targets?

[Sugarloafer80]

Wealth of info in this thread! THe mild hybrid (RR3.0 TT mild was nothing more than a bit of an electric assist for the turbos). This qualifies as my first true hybrid. Actually got a pure EV before this....different learning curve and operational philosophy.......

 

[RUN-8]

Good thing you said this because I saved time by not bothering to reading the rest. I guess kinematic viscosity at 100C that all manufacturers report is not a thing.

I should have clarified on that a bit more.

My main concern with an oil is the ability to flow when cold, I think we can both agree that in a properly functioning engine with a functional cooling system that cold starts and cold engine operations are more likely to cause damage than a warmed up engine running under load. Oil that doesn’t flow well on cold starts will definitely have the potential to cause oil starvation to bearings, and turbochargers (if equipped).

Looking at the difference in kinematic viscosity at 100C between 0W-20 and 0W-30 is pretty low. For example Amsoil lists kinematic viscosity for 0W-20 @100C as 8.8, and 0W-30 as 10.4. I doubt such a small difference in viscosity at operating temperature is going to result in any adverse effects on the service life of a turbocharger shaft or the bearings that support the shaft, or any other engine bearings for that matter.

A quick review of the linked material data sheet shows pretty small differences in the performance of full synthetic oils between 0W-20 to 0W-30. They’re nearly interchangeable in many regards.

https://amsoilcontent.com/ams/lit/databulletins/g2880.pdf

My takeaway is: use quality oil of an appropriate viscosity range, use a quality oil filter, change both regularly to remove contaminants and ensure the oil never breaks down or starts to coke.