The source of this image is Amsoil website.
The big issue with fuel diluting Ecoboost engines like the ones in the F150 and the Subaru turbo engines is fuel dilution turning 5W30 into a 5W20. I dont have any data on how this effects the engine, but I have never been comfortable with it.
Im happy I found this Amsoil study which I loosely corroborated with my own oil tests on Mobil Delvac 1 5W40. Any of the HDEO oils listed in the study would be good. One thing I might point out is the Chevron is API SN Plus which goes better with turbo gas engines.
My next batch will be the Chevron to see how it goes.
While the Amsoil may or may not be best oil here the fact is any of the HDEOs would produce a desired result in the turbo direct injected engines. That result is not seeing the oil go into the single digit CST (viscosity) range.
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