Especially during hot weather. Do you run thicker oil than 5w30 or just stick with that?

 

Some time ago, I considered using a heavier weight oil. I had experienced loss of power in the latter portions of each afternoon session when ambient temps reach 100F+.

After posting my experiences, and taking in the vast amount of member input, I changed over to a full synthetic (was using dino oil before), and added an oil cooler. I might have been OK with just full synthetic, but I didn't want to take any more chances. I also called Redline Oil's tech dept, and asked them for recommendations; they said 5w30 for a stock powered Z, even in 100F track conditions.

I haven't had any problems with power loss since.

 

I agree, I run 5W30 royal purple and its fine. Adding a oil cooler is actually a perfect combination for the track because it keeps those oil temps in the norm range.