Possible impact of not using the additive: If your classic cars are left stationary for extended periods of up to seven months, condensation can form in the fuel system. This condensation can cause various components within the fuel system to corrode. The components of the fuel with a low boiling point can evaporate, resulting in a sticky residue on the carburettor and injectors, as well as on the electric pump. After the vehicle is left stationary for long periods, the engine may no longer start, may jolt or may not fire on all cylinders. What amount of additive is recommended? The 300 millilitres of Porsche Classic fuel additive supplied in the container is sufficient for fuel tanks ranging from smaller ones such as the 50-litre tank in the Porsche 356 up to larger tanks with a capacity of 90 litres, such as in the Carrera GT. The fuel additive remains effective for stationary periods of up to seven months and its performance only begins to gradually decline after this length of time. The Porsche Classic fuel additive can be used in all classic Porsche cars. What’s on the inside counts when it comes to optimum car care – and as you would expect, we leave nothing to chance in this respect.