Love this forum, everyone is very helpful and also help solidify my oil selection on my last track toy / weekend car, which was a 2013 ZL1. I currently have a 2016 C7 Z51 Corvette with a dry sump that holds 9.8 qt of oil. The car is only driven on the road course, autocross and then on the streets during the weekend. I live in Houston Texas, so it rarely gets cold here. GM recommends Mobil 1 Full Synthetic 5W-30 but if you're tracking it to use Mobil 1 Full Synthetic 15W-50. Since I primarily track the car with some weekend cruising I just keep the 15W-50 in the car and make sure it is warmed up sufficiently before I drive it around. Prior to the Corvette I had a 2013 ZL1 and used Pennzoil Platinum Ultra 5W-30, it saw temps just below 300*F and even sometimes peaked at just over 300*F however oil analysis always came back fine. I was very impressed with that oil, unfortunately Pennzoil doesn't make the Platinum Ultra in 15W-50. So do I stick with the Mobil 1 or go with something else? Based on my oil analysis with the Pennzoil I found that 3-4 track events, plus some daily driving all around 3,000 miles total was a good point to change the oil out, so I will be using the 3,000 mile interval as my starting point. The car currently has just over 4,000 miles on the engine and about 3,000 on the oil so I will be making my next change very soon. The oil that is in the car currently that has 3,000 miles on it is the 15W-50 and the car seems to run fantastic.