There should be two settings with the XPT stage 2 LC.
Something about RPM
And something about Speed.
The RPM is your redline minus the number. So if your redline is 7k, and you put in 2k for the value, it will rev to 5k. If you put it at 3k, it will rev to 4k.
The Speed value in MPH will be when it turns off. Set it to like 3mph, so when your car reaches that point, the LC will turn off. Setting it high like 30, means until you reach 30mph, you will not be able to go higher than the RPM set by you.