Some hocus pocus worth a read:
Impact of Fuel Injection on Dilution of Engine Crankcase Oil for Turbocharged Gasoline Direct-Injection Engines
Online Oil Dilution Measurement at GDI Engines
I haven't seen ANY hocus pocus concerning oil companies.
For the 2.0T, Hyundai recommend 5w30, 10w30, 5w40, 15w40, and 20w50, SM GF4 A5 or above.. The 5w30 is for 'better fuel economy'. The 5w40 can be used in the full outdoor weather/temperature range as the 5w30.
Spend some time with owners of failed 2.0T and 2.4GDI's and see how they feel about Hyundai's recommendations for better fuel economy and textbook dealer maintenance. Anyone want to guess how many thousands of 1.6T/2.0T/2.4GDI that have been replaced under warranty or via class-action lawsuit assistance?
Synthetic oil does not protect against fuel dilution any better than conventional, and does not make up for misengineering at the OE or supplier level. Best way to help with fuel dilution is thick oil and/or short severe interval oil changes to remove the fuel diluted oil. Takes more fuel to dilute a 40 grade to point where damage can occur from oil film failure caused metal:metal contact. Obviously, keep that oil level full. 8 ounces of fuel dilution will be more damaging with 3-4qt of oil in the sump vs having the 5qt+ full capacity.
I've read nothing from Hyundai that has stated the oiling issue has been fixed on newer models. It could be as simple as a better state of tune(and you wonder why there was a horsepower drop with the LF vs YF), better engine/oil temperature control, increased bearing surface area, more oil flow/PSI, .... or engine parts washed better prior to assembly :wink: