Due to the low TBN for such low OCI miles, I have to keep in mind that this engine is the EarthDreams 2.4L engine(DI) and the very low miles for the year of the car(< 5K/yr ave.). And too, the oil was run for almost 1 yr.
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Valvoline EP 0w-20 - 5.5k miles 2016 Honda Accord K24W 28k Miles
- Thread starter cutlassvillager
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I had specifically switched to using higher octane (mostly 89) more frequently to see if it made a difference in this 2nd UOA. I frankly wasn't anticipating a change, but since fuel dilution went down I was very interested in seeing everyone's feedback! I feel like throttle response improved slightly along with a smoother idle but I assumed it was very likely a placebo effect.
I appreciate all the discussion here about it and am now having a hard time deciding if I should just continue with 89. I know it would be cheaper to just change the oil even earlier (or run it as is) but I would rather just avoid the fuel dilution altogether if it is as simple as using 89. With the relatively high MPG and low miles I average each year, the additional cost for higher octane is pretty small for less fuel dilution.
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When doing your Octane-rating calculus, include the difference in temperatures between the UOA's. The cooler the ambient temps, the more likely you'd see fuel dilution as cold temps demand richer fuel trims. Higher Octane-rating wouldn't help in this case.
BUT. the higher the running temps, the more likely some carbon buildup in the combustion chamber would yield a hot tendril that could contribute to a premature ignition event, which could result in the ECU sending a bit richer fuel mixture...in which case, a higher Octane-rated fuel might prevent the event.
Run the higher octane for 5,000 miles a year, change the oil, and save the uoa money.