This is the fourth sample in the current OCI. If you take a look below and see the Valvoline UOAs they are all from the same OCI. I keep sampling after track events. Another thing to note is that I keep adding top-up oil which actually refreshes the oil's viscosity, additive package, and also lowers fuel dilution and oxidation present. In my mind, that means I can actually run a longer OCI since I am effectively changing the oil every 5 track events. I don't think replenishing the oil lowers the wear metals (either absolute or relative terms) since the oil that burns up is replaced to the same level and I assume the wear metals themselves don't burn up, so the ppm figures stay the same (total # of particles / oil volume). If that's wrong, let me know. I will be changing the oil soon since I am upgrading the oil cooler. I will try Driven DI50 and Red Line 15W50 and then see which one does best.
Using results from my VOA, it appear that Mobil1 15W-50 actually sheared much worse when compared to any of the VR1 UOAs. Previous UOAs from this OCI are in this thread.
Notes from report:
-9496 miles, 216 engine hours on engine
-2288 miles (street+track), 48 engine hours (street+track) on current OCI
-Took oil sample with vacuum pump through dry sump dipstick tube after a few hundred miles of track driving and associated street driving (while towing a light tire trailer). Oil temperature when sampling was around 185-195F. Added two quarts of top-up oil. Engine was idled about 5 seconds before being shut off. I waited around 5-10 min after engine shutdown before taking sample. Since last sample I've added 1073 miles (800 street miles, 200 track miles), 20 engine hours (with 6 of those as track engine hours over 3 track days). However, I did not change the oil so it's cumulative with the other Valvoline UOAs.
Using results from my VOA, it appear that Mobil1 15W-50 actually sheared much worse when compared to any of the VR1 UOAs. Previous UOAs from this OCI are in this thread.
Notes from report:
-9496 miles, 216 engine hours on engine
-2288 miles (street+track), 48 engine hours (street+track) on current OCI
-Took oil sample with vacuum pump through dry sump dipstick tube after a few hundred miles of track driving and associated street driving (while towing a light tire trailer). Oil temperature when sampling was around 185-195F. Added two quarts of top-up oil. Engine was idled about 5 seconds before being shut off. I waited around 5-10 min after engine shutdown before taking sample. Since last sample I've added 1073 miles (800 street miles, 200 track miles), 20 engine hours (with 6 of those as track engine hours over 3 track days). However, I did not change the oil so it's cumulative with the other Valvoline UOAs.