Ester/Dino/Synthetic Oil - Your usage.

ChrisSlicks

I'm still on the Nissan Ester oil, I may change to something else later once I hit 5000 miles. Not sure what oil that might be yet.

Travis is right on about oil viscosity. Here's a couple of typical viscosity numbers for you.

Sorry about the formatting, doesn't want to space correctly.
_________5W-30 ________ 15W-50
100F ____ 57 cSt ________ 143 cSt
220F ____ 10 cSt ________ 20 cSt

So the 15W-50 is nearly 3 times as thick at air temperatures, but twice only twice as thick at high temperatures. As the oil temperatures continue to climb towards 260 the viscosity is going to be close to 5W-30 at normal cruise around town temperatures.

Basically the oil is going to hold up better at the track but you might pay the price of increased start-up wear so it's not a good choice for a daily driver oil.