Engine Tuning

Engine tuning is the adjustment, modification of the internal combustion engine or modification to its control unit, otherwise known as its ECU (Engine Control Unit). It is done to yield optimal performance, to increase an engine's power output, economy, or durability. These goals may be mutually exclusive, and an engine may be detuned with respect to output (work) in exchange for better economy.

It has a long history, almost as long as the development of the automobile in general, originating with the development of early racing cars, and later, with the post-war hot-rod movement. Tuning can describe a wide variety of adjustments and modifications, from the routine adjustment of the carburetor and ignition system to significant engine overhauls. At the other end of the scale, performance tuning of an engine can involve revisiting some of the design decisions taken at quite an early stage in the development of the engine.

Setting the idle speed, fuel/air mixture, carburetor balance, spark plug and distributor point gaps, and ignition timing were regular maintenance items for all older engines and the final but essential steps in setting up a racing engine. On modern engines, equipped with electronic ignition and fuel injection, some or all of these tasks are automated, although they still require periodic calibration.