[Petah78]

Originally Posted by DarkSunrise

Nice, thanks for the data point. That UOA does look very solid. Out of curiosity, how many track days had the engine seen at that point?

I think the only thing that concerns me about PUP 5w30 is its KV 100 value is lower than most other 30 weight oils I've looked at:

PUP 5w30: 10.3
Castrol Edge 5w30 EP: 10.8 (2.9 HTHS)
M1 5w30: 11.1
M1 0w30 AFE: 11.5
Castrol Edge 5w30 LL: 11.6 (3.5 HTHS)
Pennzoil Euro L 5w30: 12.6 (3.5 HTHS)

I'd bet any quality synthetic 30 weight oil would be fine though. BTW I get the sense that Subaru is much more likely to void the warranty for track use than for using a 30 weight oil.

The engine was fairly young, it was low mileage (about 18k miles) and has only seen 3 track days. That sample was taken after the last track day.

Yeah, the PUP is a bit thinner but the results are there. I have regularly got the oil temp to about 110C even when i am hooning hwy ramps. In my opinion, i don't think oil temp is as a big factor as the internet makes it out to be. I am sure there are added benefits if you run cooler oil during track use but you are also running other risks outside of track (longer oil warm ups, over cooling, leaks) which can also destroy your engine. It really depends on your usage case. In any case, don't want to turn this into oil/cooler discussion as there are already too many horses killed in this discussion.

Good point about tracking/warranty. I wonder our ECU logs anything that can indicate how the car was driven.