Chiptuning is the modification of the engine controller (ECU) software to change how it operates. Most often it's about increasing power and torque, but improving the engine's smoothness or optimizing fuel consumption can be just as important.
How it works
An engineer reads the original file from the controller, modifies the relevant maps (fuel, boost, torque) and uploads the modified version back. The whole operation requires knowledge of the specific powertrain and experience - which is why files on Hextuni are made by real engineers, not bots.
When it makes sense
Chiptuning works best on turbocharged engines, where factory maps often leave headroom. On naturally aspirated cars the effects are smaller. It's always worth consulting the scope of modifications with a specialist.