Tune Info

ECUs

During the early 1980s, vehicle technology changed significantly with the implementation of computer technology. Electronic Control Units (ECUs) were introduced to improve performance and efficiency. In the early days ECUs controlled just a handful of processes. Following advances in both electronic and computer technology, ECUs now control a vast number of electronic and mechanical processes. Signals transmitted from sensors located on the engine and chassis provide vital information to the ECU so that real time adjustments can be made. Engine speed, boost pressure, fuel pressure, cam timing, lambda and pedal position are just a few examples of the parameters measured by an ECU and the parameters it can control.

Maps & Remapping

An ECU has a piece of software (or program) loaded onto it, which controls the hardware components of an engine. This program is often referred to as a map. However, a map file extracted from an ECU will actually contain several maps. For example, a Boost Map, Fuel Pressure Map and an Injection Quantity Map. By extracting the map data from the ECU, the individual maps can be modified and reloaded to the ECU. If these maps are recalibrated correctly, the performance, drivability and efficiency of an engine can be improved. This process is called remapping.

The Factory Detune

In many cases, the performance of a vehicle with factory settings is so far away from the engine’s true potential that it could be said that they are electronically detuned by the manufacturers. This may seem hard to believe, but there are many reasons for this, which we will touch on below.

When a vehicle is manufactured for global sale it must be able to cope with many different environments. The vehicle must be able to deal with the poor quality fuels sold in less developed countries, perform at high and low altitudes, cope with poor or non-existence servicing and perform with severe differences in atmospheric temperature. For example, a vehicle manufactured in Japan must be able to cope with the high air temperatures of India, but also perform in the freezing winter conditions of Russia. Therefore, when a manufacturer is producing a map for a vehicle to be sold globally, it is forced to make a compromise between performance and the vehicles ability to run well in a range of different environments. There are also stringent regulations on the exhaust emissions of new vehicles and political pressures to produce ‘green’ vehicles. Given these factors, it is understandable that manufacturers detune their vehicles from the factory.

Luckily, here in Australia we do not have many of the environmental conditions and other issues described above. We have average quality fuels and a pretty good servicing regime in addition to not having to conform to the more stringent emissions controls to that of Europe, so we can tune vehicles without having to compromise on reliability. We are also able to finely tune vehicles so that they perform to their maximum potential specifically for the Australian climate.

Significant Performance Gains

You may wonder how so much power can be extracted from some vehicles. Certain vehicles offer unbelievable gains in power and torque following a remap. Often the vehicles that offer the best increase in power and torque were severely detuned from factory. It is now common practice for a manufacturer to produce one engine, yet offer several different power options. For example, the Ford Transit 2.2 TDCI engine has four available power options: 85hp, 100hp, 125hp, and 155hp. How is this possible when the engines are all the same size and all have identical hardware? The difference comes down to the map loaded onto the ECU from factory. Basically the 85hp engine is a detuned 155hp engine, the 155hp model can be tuned to 180hp, therefore the 85hp model can also be tuned to 180hp. That is a final increase of 95hp.

Altering a Map

Altering a map is a complex process, which is difficult to explain fully here. However, we have covered some of the basic points below.

The internal combustion engine works by burning fuel and air, converting this chemical reaction into kinetic energy. By remapping an ECU, we can alter the amount of air and fuel that enters an engine. On a turbo vehicle, we can increase the air quantity by increasing turbo boost pressure and we can also increase the fuel quantity by altering the fuel injection maps. If you alter the amount of fuel and air injected into the combustion chamber you can alter the power, torque and efficiency output.

Unfortunately, it is not quite that simple. Many other factors also come into play when tuning a combustion engine. You must also consider at what point in the engine cycle should the fuel be injected, how long the injection period should last for and at what point the fuel should be ignited. Remapping is about fine-tuning and getting the balance correct for that specific engine design.

Here are some of the parameters that are altered during a remapping process:

• Injection Quantity
• Injection Duration
• Injection Pressure
• Turbo Boost Pressure
• Spark Advance
• Pedal Maps
• Torque Limiters

Bench Tuning

Remapping a vehicle through its OBD port is not always possible for various reasons. The vehicle may not have an OBD port, the port may be faulty or the ECU may be tune protected (systems put into place by the manufacturer to prevent ECU data from being modified via the OBD port). Bench tuning is the nickname given to the process of removing the ECU from a vehicle and making a direct connection to the internal circuit board of the ECU on the work bench. There are several different methods of communicating with the ECU and the method used depends on the type of ECU and the internal microprocessor. 

BDM or Background Debug Mode is the process of connecting directly to the circuit board of an ECU, using a specially engineered jig to hold the ECU in place while data pins are connected to the circuitry. Other methods include Boot Mode, Pin Out, JTAG, etc.

Chip Tuning (Chipping)

Early ECU systems contained EEPROMs (AKA Chips) which stored the map data. To read the data programmed to these chips, tuners often de-solder the chip from the board and place the chip in a chip reader. This data would then be modified and reloaded on to the chip. However, the chips fitted to some early ECU’s were often OTP (One Time Programmable) meaning that although the data could be extracted from the chip, the new modified map data could not be programmed back onto the same chip. To overcome this, the tuner will program a new chip with the modified data and solder the new chip to the circuit board. This process is often nicknamed ‘chip change’.

Since the introduction of multi programmable chips and MCUs, tuners have adopted faster, cleaner and less detectable methods of remapping i.e. OBD and BDM tuning. Although it must be noted that there are still many cars on the road today that have to be chip tuned albeit this is reducing as time goes on.

Although these processes are very different, they are all methods for remapping.

We hope you have found some of this information useful and now have a better understanding of what remapping involves and how electronic tuning can alter the performances and characteristics of a vehicle.