1.replaceable
2.Writing
3.External type

This introduces three ways of ECU modification. ECU modification is just a general statement, which can be divided into modification that directly changes the hardware of the ECU calculator and modification that changes the internal program. There are three main ways to "deceive".

●replaceable
Directly changing the hardware of the ECU calculator is the "replacement computer" that is very common in the racetrack. Using the "full-time replacement ECU" to control the engine, such as Motec, Haltech and other brands, is the well-known full replacement computer. This modification It is usually used with heavy engine hardware modification. Since the working temperature, intake air volume, fuel injection amount, compression ratio and other data of the modified engine are far beyond the original factory setting range, that is to say, the engine has undergone a very large modification operation. Afterwards, when the original ECU is completely unable to meet the hardware requirements, this competitive product is the most suitable choice.
The replacement computer does not need to take into account the limitations of the original data at all, and all data are set by the technician at will. Although replacement computers are extremely adjustable, they also have to start from scratch because there is no fixed form and size. This makes the requirements for technicians very high. As for how difficult it is, it is not unusual for a day or two to adjust the idling speed after the vehicle is started normally, so this kind of replacement computer is mostly used for professional teams regardless of the cost.

●Writing
The write-in modified ECU retains the hardware part of the original ECU, and adopts the method of writing the new operation management program into the ECU program. Because the original factory setting program is changed, the write-in ECU is also called rewriting ECU or folks often say brush the computer. Although this modification method is limited by the original ECU and sensors, and the adjustment range is relatively small, it has been favored by more modification players in recent years because it will not destroy the use of other functions of the original factory and is more stable and safe. .
Many brands will launch ECU programs corresponding to specific models. At present, some of the more popular write-in ECU modification brands even publicize that their ECU programs will be based on local oil, climate and other factors. The horsepower-increasing type is even more fuel-efficient than the original ECU modification program.

●External type
The plug-in modified ECU is simply to change the execution program by "secretly" replacing the signal to deceive the ECU with the protection program. First of all, the plug-in ECU intercepts the signals fed back to the ECU by each sensor, and modifies the signals that need to be adjusted (which can be understood as cheating, the purpose is to deceive the original ECU), and turns the signals that originally exceeded the upper limit approved by the original ECU into The normal signal is input to the original ECU. After receiving the "normal signal", the ECU outputs the execution program set by the original factory to the plug-in ECU. At this time, the plug-in ECU modifies the signal (the command issued by the original ECU is not suitable for execution at this time. components work).
After the above series of actions, a successful deception is complete. The adjustable range of the external modified ECU is between the other two methods. However, due to the increasingly powerful performance of modern automobile ECUs and a higher degree of self-protection, the operation of plug-in computers is becoming more and more difficult.

In general, the three methods have their own advantages and disadvantages. The alternative type is suitable for heavy modification or even competitive modification. The flash type is suitable for the original ECU with strong protection and mild modification. The external computer is suitable for mild to moderate modification. It corresponds to the original ECU which is easier to modify the data.