Basically, tuning is all about altering the way the motor runs. Primarily it’s about getting more power from the motor, by getting right air-fuel ratios, the right ignition timing advance, and the right boost levels.
There are generally three steps to tuning:
1) Make some data logs to see what’s going on in the motor in the first place.
2) Read and study those data logs.
3) Make changes to the tables that govern fueling, timing, boost, and so on.
4) Go back to step 1, and see if your changes had the desired effects.