Sure, I can try and explain what you're looking at. Usually the dyno graphs show rpm's (rotations/revolution per minute) along the bottom axis (x-axis). Along the vertical axis (y-axis), either torque (ft-lbs) or horsepower will be shown. Now the line that is plotted represents a specific horsepower or torque values at corresponding rpm's. This plot is very helpful because one can see where there are power losses and gains. One can then tune to add power where it is desired. Hope this helps.