Altrodesigns

I'm running an LRP Quantum Super Sport in my 1/18th M18. On the ESC there is a little power dial that you can change. I remember making a change once. in the + direction, and it made a huge difference in speed. How far should I be able to turn it in the + direction? I'm just running stock motors. Right now (for those who have this esc) the dial is turned to the tip of the arrow by the +. Any help would be great, Thanks.