I've seen few posts mentioning adjusting track times for elevation. I am curious about how elevation effects performance. I have two questions:

1. Are there formulas for adjusting track times or other performance measurements based on elevation.
2. I live in utah, where my elevation is 4356 ft above sea level. I am running the 91 Extreme tune from Evolution. Should that tune be adjusted for my elevation. Would I see any performance difference?

What are the facts regarding elevation and vehicle performance?