Why is it important to data log one with normal driving conditions you can see pids like map sensor data fuel trims spark engine knock or o2sensor data short term field trims long-term field trims that way you can see if you have any issues with vacuum leaks fuel delivery. This is a big park with drag racing so that way when you’re launching a vehicle, you can see how the car is responding from start to finish in between runs and then you can send that log to whoever your tuner is and your tuner can adjust or say hey, try this or try that, and then go from there