Editing Engine tuning (section)

==Remapping==
{{Unreferenced section|date=December 2018}}
Remapping is the simplest form of stage one engine tuning; it is performed mostly on [[Turbo charger|turbocharged]] vehicles containing a modern [[Engine Control Unit]] (ECU). Almost all modern vehicles have an ECU, primarily supplied by [[Robert Bosch GmbH|Bosch]] or [[Delphi Technologies]]. The ECU has [[firmware]] that controls the various parameters under which the engine runs. These parameters include achieving the appropriate balance between fuel consumption, power, torque, fuel emissions, reliability and service intervals. In seeking this balance, many factories firmware do not prioritise power or torque, which means it is possible to increase the performance of the engine by remapping the ECU.

Many manufacturers build one engine and use several firmware versions, known as maps, to achieve different power levels to differentiate vehicles that essentially have an identical engine. This gives users an opportunity to unlock more power from the engine with a few changes to the factory software by reading and editing the factory firmware from the ECU using specialist tools plugged into the [[on-board diagnostics]] (OBD) port. The tools can be connected to the OBD port on any car to read the [[Engine Control Unit#Programmability|factory file]] that is saved on the ECU. Software to read specific types of factory files is available.

Parameters of factory files such as fuel injection, boost pressure, rail pressure, fuel pump pressure and ignition timing, are adjusted to safe limits that are set by an expert so the unlocked performance does not compromise the car's safe levels of reliability, fuel consumption and emissions. The map may be customized for city use, for on-track performance, or for an overall map giving power throughout the band in a linear manner. Once adjusted, the edited file is written back to the ECU with the same tools used for the initial reading, after which the engine is tested for performance, smoke levels, and any problems. Fine-tuning is done according to the feedback, producing a better-performing and more efficient engine.

Remapping may increase the temperature of [[exhaust fumes]].