I May start my own thread on this in the UOA section, but i had hoped to add to THIS discussion with my own 3.5 ecoboost partial UOA history.
MY interpretation is that fuel dilution ramps up quickly
the quality of the oil can matter; obviously viscosity does as well.
MY interpretation is run-of-the-mill (Walmart) synthetics are played out much sooner than some boutique brands. Of course, some “run-of-the-mill Euro oils (Castrol, Mobil, Pennzoil, QS) MIGHT hold up better. I don’t have any UOA’s on them (except in a Subaru…which looks MUCH better on paper…but it’s pre-DI EJ255 turbo.)
the one boutique oil I have experience with in this engine is Valvoline Premium Blue Restore 10w30…an oil which might share a fair amount with one or more of HPL’s oils. It did pretty well “combatting“ fuel dilution, IMHO, over more-extended OCI’s; much better than Pennzoil (SN PUP & SN+ PP), QSFS SP, and even Castrol Edge SP (which perhaps did better than the others). My current fill is Amsoil Sig Series…I have no idea how it will do, and after that, I have some HPL PCMO queued up.
sample 1: Pennzoil Plat 5w30 SN+
sample 2: PUP 5w30 SN. **note fuel dilution at low miles **
sample 3: Valvoline Premium Blue Restore 10w30 (HDEO SN) “cleaning oil”
sample 4: QSFS 5w30 SP
sample 5: Castrol Edge 5w30 SP. **vehicle sat for summer & fall months…not driven; oil changed after brief warmup**
I have other UOA’s from TestOil/Dyson on the VPBR. Viscosity always stayed above 10.1, usually 10.7ish. dilution ranged from 2.1 to 5.3. Dyson OCI’s were ~7500-9600 mi.