Servo adjustment/settings

EPA is the short cut of End Point Adjustment.
With this function you can limit the amount of travel a servo can turn in each individual direction.
EPA can be set for throttle and steering servo normally.
On some transmitters this function can have a different name like ATV or Balance.

Transmitters having EPA for the steering servo also have an extra function for servo travel for both sides together, called Dual Rate.
EPA and DUAL RATE are two fully different functions but are related to achieve correct setting of the servo.

Below follows the routine to set up your EPA and DUAL RATE the right way for steering and throttle/brake.
Correct settings will save the servo from straining and ensures a trouble free running car.
We use a KoPropo Mars EX-1 as example. Your transmitter might have a other display, optical settings or names.
Some cheap transmitters do not have EPA or DUAL RATE settings possible!

Please check the manual that comes with your transmitter first before you start with the routine

First switch on the transmitter!
epa-001.jpg (73835 bytes) Set the DUAL RATE for the steering at maximum setting.
With the MARS EX-1 Mars it is called ST:TRAVEL
epa-002.jpg (74822 bytes) Set the EPA for LEFT steering at minimum setting.
With the EX-1 Mars it is called ST:BLANC L
epa-003.jpg (69481 bytes) Set the EPA for RIGHT steering at minimum setting.
With the EX-1 Mars it is called ST:BLANC R
epa-005.jpg (75160 bytes) Put the steering trim in Neutral position

epa-017.jpg (73166 bytes)

 Set the DUAL RATE for BRAKE  at maximum setting.
On some transmitters this is a dial wheel or knob on the grip that works for BRAKE side only.
With the MARS EX-1 Mars it is called T: TRAVEL
epa-019.jpg (69935 bytes) Set the EPA for Throttle at minimum setting.
With the EX-1 Mars it is called TH: HiPOT
epa-020.jpg (75471 bytes) Set the EPA for Brake at minimum setting.
With the EX-1 Mars it is called TH: Brake
epa-022.jpg (70253 bytes) Put the Throttle/Brake trim in Neutral position
epa-013.jpg (89364 bytes) Remove the servo arms from the servo!

Switch ON the receiver!
Check by steering and moving the throttle trigger if the servo direction is correct.
If not use the servo reverse on your transmitter to get the right rotation direction.
epa-006.jpg (82789 bytes) Put the steering servo arm on the output in the nearest 90 degree angle possible and secure it with the screw.
epa-008.jpg (74787 bytes) Set the SUB trim so the servo has a 90 degree angle.
epa-007.jpg (78226 bytes) This is the correct 90 degree angle setting
epa-009.jpg (78665 bytes) Make the rod that connects the servo arm and the servo saver arm shorter or longer so the white lines are parallel.
epa-010.jpg (78096 bytes) Set the right amount of length of toe in or toe out for both steering arms the same.
epa-011.jpg (65668 bytes) Turn the steering wheel full left and enlarge the amount of EPA so the servo has maximum travel without making rumbling noise or feels strained. Move also the suspension arm in compressed position and check again.
epa-012.jpg (64464 bytes) Turn the steering wheel full right and enlarge the amount of EPA so the servo has maximum travel without making rumbling noise or feels strained. Move also the suspension arm in compressed position and check again.
Put the throttle/brake servo arm on the output in the nearest lengthwise possible position and secure it with the screw.
epa-018.jpg (74362 bytes) Set the throttle/brake SUB trim so the servo arm is in a 0 degree lengthwise position.
epa-015.jpg (98885 bytes) This is the correct lengthwise setting
epa-016.jpg (93929 bytes) Now slowly open the throttle on the transmitter.
Keep it in full throttle and enlarge the amount of EPA so the servo has maximum travel and the carburator barrel is fully opened without straining the servo.
Roll the car and feel  if it runs free on the ground.
If not put less pressure on the brake stoppers by using a 1.5 mm hexagon tool or turn out the knurled stoppers.
Make sure the brake stoppers are adjusted that in neutral position the brakes are just not working and the brake disks run free!
epa-014.jpg (95882 bytes) Roll the car on the ground and slowly increasing to full brakes.
If the car is not braking increase the brake EPA setting on the transmitter till it does.
The car must give resistance at a certain point
Always check if the you give full brake the servo is not straining to hard.
Now adjust with the knurled stoppers the brake BIAS between front and rear.
Check that the throttle pressure spring at full brakes is not compressed fully but still has some compression space left.
Lift the rear of the car and check by rolling the car the brake resistance with full brake.
Lift the front of the car and check by rolling the car the brake resistance with full brake.
Try to set the brake bias level at 60% to the front and 40% to the rear by turning the knurled stoppers.
Brake BIAS and amount are track and driving style related and must be set accordingly.
Switch OFF the Receiver
Switch OFF the Transmitter

TIP

 If you change any setting on the front geometry of the car like toe in/out, camber or caster always check and readjust the EPA again.

 

 

© All rights reserved by