This is a used oil analysis from a double 7 (14 hours total) race weekend in a very stock (motor) 1.6 Miata racecar. This car has megasuirt and a 4-2-1 header and makes 124whp. Other than that it is a motor of unknown miles and condition. 2 years ago it had 5-10% leak down on 3 cylinders and 15% on one (cold). Approximately a 1/2 quart was added at each pit stop (1.5-2 hours). The Kendall monograde sae30 used is not a HDEO and is SN (possibly SN plus, do not have bottle in front of me). I am utterly amazed with the performance of this oil especially its value. However I feel this performance is more due to the quality of the mazda engine and oil control in this kind of application. How can I improve on this performance? Why did the oil lose viscosity with only trace fuel? Did this monograde shear? What is the next oil, SAE 40? HDEO 15W40, HDEO 5W40, another SAE30? Thankyou for your input!