Turbo delay is the time from the throttle stick/trigger is moved to the full throttle position and keeps at that point to the moment Turbo Timing is really activated. If you set this item to “INSTANT”, then the Turbo Timing will be activated right after the throttle stick/trigger is moved to the full throttle position. If set it to any other values, then you need to keep the throttle stick/trigger at the full throttle position for a while (as you set) till the Turbo Timing initiates.
Note:"Turbo Timing" and "Turbo Delay" only function when you set the “Drive Mode” to “Full Sensored”.