Oil filter was a Fram Ultra Synthetic.
2020 Subaru Legacy 2.5L / M1 EP 0w20 / 20,799 mile OCI
- Thread starter iunderpressure
- Start date
Oil filter was a Fram Ultra Synthetic.
cut the filter open 
Great run!
The ending viscosity of this sample is 7.89. The minimum for 20 grade is 6.9, so this oil looks to me like it's right below the midpoint of the 20 grade range of 6.9-9.29. And it looks like every other sample on this sheet has stayed in grade (barely).
Having a beginning and ending oxidation value would tell us a lot here. Blackstone does not test for this though.
A 375 flashpoint indicates more than 0.5% fuel. BS values are usually 2x-4x lower than results of the sample with gas chromatography, so I'm guessing your actual fuel% is 1.5% to 2%.
1qt
High silicon...
Nice run! Iron tracked almost identically for ppm/1k mi, viscosity still in grade, and TBN just barely at the edge of condemnation. You definitely hit the sweet spot this run! Fuel/flashpoint doesn’t bother me one bit because everything else is just peachy. 
Strongly suggest not running such a long OCI without also checking TAN. Not saying the oil needs to be changed sooner, but you don't have a complete picture as TBN depletion tends to bottom out once you get into extreme intervals.
As mentioned above already, there's also the issue of whether GDI soot load in the oil is abrading components, even if the oil itself can make it this long. I used to do 15k OCI's on port injected cars, but limit to 5k in my GDI engines purely because of this. I don't bother with UOA's these days as oil degradation is not the constraint.
As mentioned above already, there's also the issue of whether GDI soot load in the oil is abrading components, even if the oil itself can make it this long. I used to do 15k OCI's on port injected cars, but limit to 5k in my GDI engines purely because of this. I don't bother with UOA's these days as oil degradation is not the constraint.
20000 miles on a finicky Subara engine. Gutsy....
Check your airbox to see if the silicon is from dust. I've had sealing issues with an aftermarket filter on my Subaru. It's also easy to miss one of the lower hooks when closing it back up.
Iron/mile is worse than for your shorter runs. Normally it trends down over the OCI, then starts increasing again. I'd consider this to be a condemnation point. TBN is also uncomfortably low. A 10-12k OCI seems reasonable. I certainly wouldn't go past 15k again.
Iron/mile is worse than for your shorter runs. Normally it trends down over the OCI, then starts increasing again. I'd consider this to be a condemnation point. TBN is also uncomfortably low. A 10-12k OCI seems reasonable. I certainly wouldn't go past 15k again.
This is my first run with M1 EP 0w20. All the other runs were with Costco 0w20.
I think this test looks pretty good, and I plan on running another 20,000 mile oci. I put miles on very quickly.
I think this test looks pretty good, and I plan on running another 20,000 mile oci. I put miles on very quickly.