Chip tuning refers to changing or modifying an EPROM chip in a car’s or other vehicle’s electronic control unit (ECU) to achieve better performance, whether it be more power, cleaner emissions, or better fuel economy.


The days of manually pulling and replacing EPROM chips from a factory ECU are long over. Chances are, a “chip” for your modern car is nothing more than a software upgrade that’s reflashed onto your ECU’s memory via the onboard diagnostic (OBD-II) port. Modern ECUs can be tuned by simply updating their software.

The Electronic Control Unit (ECU)

ECUs are a relatively recent addition to the automobile, having first appeared in the late 1980s.As technology advanced, so did the electronics that go into cars. The ECU in a modern automobile, together with advanced engine technology, makes it possible to control many aspects of the engine’s operation, such as spark timing and fuel injection, Throttle, Valve timing, Valve lift, and many others parameters.

Carmakers go to suppliers such as Bosch, Seimens, Motorola and Magneti Marelli for engine management systems (EMS).


These are complete electronics packages including the engine and transmission control units and any additional modules. The primary part of these EMS systems is the electronic brain, called the ECU. All the vehicle’s sensors required to run the engine, transmission, diagnostics, ABS, traction control, airbags and even security are also supplied with the integrated system. Between the car manufacturer and supplier, each system is custom designed and the software calibrated for each vehicle. Model year differences and sometimes option levels might also require different software calibrations and setup. As an example, one model year of the 3 Series might use an intake air temperature (IAT) sensor in the intake manifold while other model years use an integrated mass air flow (MAF) and IAT sensor. This means the ECU software and engine management algorithm would be different. There are myriad ECU configurations out there; some differences are even based on where the car is sold. European and U.S. market ECUs are very different since the two markets have different emissions regulations and fuel grades. That’s why we can’t use chips available from European tuners such as Alpina or AC Schnitzer.

Performance increase

Performance gains are realized by adjusting the ignition timing advance. Higher timing may result in higher performance. However, to cope with advanced timing, one must run high-octane gasoline to avoid pre-ignition detonation or pinging. Manufacturers design for a lower specific timing and bad fuel quality, this may limit performance accordingly.

In addition, changing fuel maps to coincide with the best ratio for gasoline combustion may also realize performance increase. Most manufacturers tune for optimum emissions and reliable engine duration under any condition with purposes which can limit performance.


Cars with a turbo fitted can have the requested and allowable boost levels raised; these applications usually have the most effect if the turbo fitted is a low pressure turbo which leaves the most room for improvement.

Another reason to change the ECU map is if there are engine, intake, or exhaust modifications to the car. These “bolt-on” modifications alter the way that the engine flows, often causing the air to fuel ratio to change. Without re-mapping the fuel tables, some of the performance gains from the modifications may not be realized.

A good tuned ECU can result in increased performance, drive ability, and never cause engine damage, that’s why your choice of your tuner has to be more then precise and only go to professional peoples with a good knowlage in Electronics and Mechanical!

Chip tuners will take a whole spectrum of approaches to retuning your car for additional power. It has a lot to do with the type of car, level of modification, familiarity with the code and the market the tuner is trying to target. They are like artists with different philosophies, tools, approaches and abilities.


The most common way to ‘upgrade’ the ECU is using either plug in modules as mentioned above or using a special tuner device who will use an OBD / BDM /Jtag tool. These devices generally plug into the diagnostic port although in some cases the reprogramming is done directly on the circuit board. Maps are supplied by tuners.

Serial remapping

Serial port programming allows us to remap an ECU (Engine Control Unit) without removing the ECU from the car, the remapped software is uploaded direct to the ECUs EPROM via the vehicles diagnostic socket, this allows for the performance conversion to be totally invisible with no soldering or removal of components.