In the olden days, car tuning mostly consisted of adjusting carburetors and ignition to keep the engine running optimally. You also had to keep an eye on the spark plugs and various engine fluids, and make sure to keep things lubricated. More serious tuning included performance car parts such as headers, exhausts or perhaps a bigger carburetor or engine. These still play a role today, but almost everything else has changed. Computers control our cars now, and they have become the primary key to performance. Automotive computers, often called Electronic Control Units or ECUs, manage every aspect of a vehicles running and performance, from determining when exactly spark plugs should fire, to providing the data for the boost display of a turbo motor, all the way to luxury car tuning amenities such as turning lights on or off and adjusting rear view mirrors.

How do Electronic Control Units work? To begin with, they are both the same and very different from the desktop and notebook computers we use in our lives. They are the same insofar as they are computers with CPUs and memory and the programming needed to do a variety of tasks. They are different in that they have no displays or hard drives or keyboards. Most ECUs consist of a system board housed in a small metal box that's usually mounted either in the engine compartment or under the dash. ECUs are designed to do just one thing - running your car - and they do have to do that reliably and without fail for many years. ECUs must boot up instantly when you turn on the ignition of your car; they must manage fueling, ignition, cams of an engine whose camshaft may rotate up to 9,000 times a minute; they must handle emission control and various other systems that require instant changes several times a second; they must monitor dozens of sensors located throughout the vehicle; and they must do all that in temperatures ranging from blazing hot to ice cold and while rattled around on bumpy road day after day, month after month.

Given all that, you'd imagine that ECUs are totally closed systems, black boxes that you can neither adjust nor fix should they break down. Wrong. ECUs have become the focal point of engine tuning, both for domestics and imports. If you look at any catalog for luxury performance car parts you'll find various products that affect the running of the ECU either via reprogrammed chips or circuitry that intercepts and modifies signals to and from the ECU. Be it Volkswagen parts, Audi parts, BMW parts, Mercedes parts or other luxury car parts, chances are that the performance tuning section includes ECU tuning products.

What can ECU tuning do for your vehicle? Just about everything. If you add performance hardware such as headers, exhaust, a turbo, or a supercharger, ECU tuning makes sure that spark and cam timing and the air-fuel ratio are adjusted properly so you get optimal performance and reliability from your modified engine. Depending on your modifications, ECU tuning may also include injection and boost display and control, changing rev limiters, launch control, automatic transmission shift points and torque converter settings, as well as monitoring various functions. Amazingly, unlike traditional modifications, ECU tuning can be undone within minutes. It is truly 21st century style tuning.