What is an ECU?

What is an ECU?

ecuAn ECU, or Engine Control Unit, is a small computer which controls an engine. Usually “ECU” refers to an ECU on a electronically fuel injected (EFI) petrol engine. ECUs also go by several other names, such as EMS (Engine Management System), ECM (Engine Control Module), or even “chip” (derived from the practice of replacing the ROM chip in the factory ECU to retune it).The ECU usually controls the fuel injection amount and the ignition timing of the engine, along with several other functions. Because the ECU controls the fuel injection amount, it must be set up correctly, otherwise poor fuel economy, poor power and excess pollution may result.

Why do I need one?

There are four main reasons for converting a car to an aftermarket ECU:

  1. To provide greater tuning flexibility (although some original ECUs can be retuned, not all can, and often this requires specialist tools)
  2. To allow changes to engine hardware (eg removal of the airflow meter, changing to larger injectors etc)
  3. To provide more advanced functions that the factory ECU does not support (for example, adding in flat shifting, anti-lag or launch control for increased performance)
  4. To provide increased diagnostics and datalogging than the factory ECU can provide (for example, additional temperature, pressure or speed sensors).

The additional tuning flexibility is required to extract the most power and torque from the engine. While manufacturers sometimes do this well from the factory, in general they tune for a wide range of conflicting goals, such as fuel economy, low emissions, high torque, good drivabiltiy and long engine life. Thus, when tuning a race car with the overarching goal being torque and power, the tuner will arrive at a different tune from what was done by the original ECU, and make more power in the process. An Adaptronic ECU allows the tuner to do this.

Another limitation of using the original ECU is the limitation of original engine hardware. With significant increases in power (for example, due to increased boost, or applying boost to a previously naturally aspirated engine), the original airflow meter may reach its limit of reading. Simiarly, the injectors may not provide sufficient fuel flow to suit the new engine configuration. A fully programmable ECU such as the Adaptronic range allows you to use a MAP sensor instead of an airflow sensor, and use any standard fuel injector – from original size up to very high flow rates.

The Adaptronic ECU range supports flat shifting and launch control, while the e1280s ECU also supports antilag. These features allow more controlled launches, faster gearchanges and less turbo lag, increasing your speed at the track.

However one of the main benefits of using an Adaptronic ECU, especially the e1280s Super ECU, is being able to monitor engine parameters, take data logs and analyse your engine systems. For example, adding additional temperature sensors to the intake system allows the enthusiast to measure the air temperatures at the air intake, after the turbocharger and after the intercooler; thereby assisting the enthusiast to determine the next best modification to make to their car.