Just so I understand, are you suggesting that I accept this level of dilution as inevitable (given a tuned TGDI car) and make the oci decision based on how much viscosity decreases over time with increasing dilution?
Also, for my knowledge, does fuel dilution generally increase linearly over time? For example, my dilution was over 5% at 4000 miles. Would it have been 2.5% after 2000 miles?
Thank you.
Obviously, if the dilution is due to a faulty component (injector?) then we'd all agree that should be fixed.
If the fuel dilution is due to high fueling rates with the tune, that's just something you'll have to accept as part of the consequences.
However, the wear rates in your UOA here clearly show that at this level of dilution, though not desirable, there's no detrimental effects to the engine.
I advocate for using the UOA as the tool it is best suited for; tracking lube condition and tracking equipment condition. If (and this is not the case for you, but it's part of my example) your wear rates were as good as they are now, and your fuel dilution were low, I'd say you could easily double the OCI. However, though you have good wear rates, you also have an oil condition which may degrade the servicability of the lube fairly quickly, and therefore I only advocate for OCI extension by 1k mile increments.
Run a few OCIs at 4-5k miles and see if the wear rates stay consistent; they are very good at the moment.
- if the wear rates stay fine, increase the OCI by 1k miles and repeat (try 5-6k miles and if good, go to 7k miles .... )
- if the wear rates are adversely affected significantly at 5k miles, then you've reached the practical limit of the OCI
Lube conditions (vis, FP, contamination) are only PREDICTORS of WHAT MIGHT HAPPEN.
Wear Metals are a NOTIFICATION of what ACTUALLY HAPPENED.
As long as the wear rates are good, everything else is just a potential marker for a possible change in wear.