Quote Originally Posted by string View Post
Other than increased overall power output, how else do you think the car is going to go faster around the track? Unless you're going to tell me that this Royal Purple engine oil will also reducing braking distances and increase the grip of my tyres?
It's easier to control a car at it's limits when you have good response of an engine under your belt. What times, and what car you using? Just curious...

Quote Originally Posted by string View Post
So how can you compare the responsiveness in different conditions and more significantly, states of ecu tune and then attribute it solely to the oil?
Because I have switched tunes every 3 track days or so, and used different viscocities with the same tune. It's easy to feel engine response. And quite obvious when you go for an OPH run on 5W-30, then change oil to 10W-40 that day, then go for another OPH run. Different viscoties DO make large difference to engine response, and like I have said it's easier to note on some engines rather than others.