Essentially a mechanical air valve, the carburettor component regulates the ratio of air to fuel and delivers the optimal mix to the internal combustion chambers. The piston down stroke creates an intake vacuum which draws fuel and air into the combustion chamber. Positioning of butterfly valves dictates the ratio and controls the RPM.Supplying an incorrect ratio will cause the engine to run either rich (too much fuel) or lean (too much air) – both scenarios are bad, but the latter is considerably more likely to cause costly permanent damage. Engine efficiency and power delivery will suffer if running suboptimal, rich or lean.During the 1980s technology advancements saw a shift away from mechanical carburettors to fuel injection systems. These can be either direct where fuel is delivered to the combustion chamber, or indirect where fuel is combined with air prior to the intake stroke.Fuel injection is overwhelmingly more suited to road use, however for track use mechanical components that do not exert a drain on the engine can be favoured.