Electronic control units (ECU’s) in cars have been around since the late 1970’s. Believe it or not, the groundwork for modern electronic control systems had already been started as far back as 1939. A lot of development has taken place since then. In the old days you had to remove the ROM chip in order to either swap it out with another chip containing different programs, or it had to be reprogrammed externally by plugging the chip into a hardware interface in order to reprogram it. Some of these chips could only be programmed once, which meant that the chip which the manufacturer installed could only be replaced with another chip. Today, more systems are controlled by ECU’s than was the case in days gone by. The plural is used for the simple reason that modern cars can contain more than a hundred different ECU’s. All these different ECU’s are monitored and controlled by the management system. How all these systems interact with each other is far too complicated for the scope of this article.
Since we are only looking at a fairly simple explanation of what the modern ECU’s do and how they are controlled, we are not going to delve into all the things computers have irrevocably changed in our lives. The ECU’s in a car control things like the anti-lock braking systems (ABS), electronic brake distribution (EBD), engine airflow, fuel pressure, cam timing, spark timing, and various other things too numerous to mention in this article. The hard wired chips have been replaced by re-programmable computer systems. Each unit can be reprogrammed to interact differently with the other units and systems in the car, as well as change certain parameters like the volume of air and fuel ratio among various other tweaks. These programs are referred to as “maps”.
Car manufacturers load a fairly “generic” version of the maps to cars due to the varying environments in which these cars will operate after being sold all over the world. We might view it as “de-tuning” the car in order to better suit any combination of different environments. Variations in the fuel quality, temperature and ambient air pressure has quite a significant impact on the performance of a car. The more finely a car gets tuned, the more sensitive it becomes to severe environmental variations. Unless your car travels to areas with vastly different elevation, temperature, or fuel quality variations, the aforementioned sensitivity won’t be any problem. In fact, the ECU’s in modern cars cope much better with environmental variations than cars from the 80’s. It is well known that a lot of performance gains can be achieved by remapping the “generic” maps the car was sold with. Something that people don’t really view as a “performance” enhancement is increased fuel efficiency. That is just a matter of perspective though.
In conclusion, the ECU remap process really focuses on the individual car in a particular environment rather than the more conservative generalized maps it starts out with. It is even possible to get better fuel consumption in spite of increased power and torque after having your car remapped by a professional technician. This sort of mapping is commonly referred to as a stage 1 upgrade. Further performance gains can be achieved without hardware upgrades on certain models, but once a car is performing optimally, no further gains will be achieved without doing some aftermarket modifications. Examples of such modifications are fitting different air intakes, exhaust systems, turbo chargers, superchargers, gearboxes, etc.
In a nutshell, ECU tuning is not just for petrol-heads. The latter only takes the tuning to new frontiers, which may well end up improving the next new car you might buy. Even the most conservative driver will benefit by having his car’s ECU remapped.
