How do i adjust the throttle endpoints for a nitro car-- there're two EPA's for the trottle, what do both of them do?

Also, what adjustments can i apply to electric throttle EPA's, and what will they do?

one sets your EP for throttle and the other sets your EP for brake....you are just limiting how much travel the servo has both ways from center.....make sure you open your carb and look down the throat set your EPA to stop as soon as it hits 100% open...DO NOT let it move ANY more than this...especially if you use digital servos...you'll blow it up....the brake is alittle more tricky..use a peice of fuel tubing instead of the spring on the linkage and set it to the point it locks the brakes up and you can't push the car easily......steering should be a no brainer....