FROM MECHANICAL TO CONTINUOUS INJECTION SYSTEMS
Like all car manufacturers, Porsche used carburettors. The early 911 had bespoke Solex units designed for it, but these proved unsatisfactory and were soon replaced by Weber items.
Carburettors are the age-old method of combining the petrol-air mixture for combustion engines and work by the suction created by the downward stroke of the pistons, with fuel delivered by a pump usually running off the crankshaft. Cheap and reliable, the drawbacks of the carburettor, essentially a non-pressurised system, are a tendency for fuel starvation under high cornering forces and their inability to provide optimum fuelling at very high RPM. In motorsport, Porsche had been fielding class winners for a decade, but as its competition ambitions increased under Ferdinand Piëch, extracting as much power as possible from its relatively small-capacity engines became a priority. The 906 was the first sports racer to experiment with a Bosch-derived injection system, and competition advances soon found their way into production engines.
Differing from the classic carburettor, fuel injection is pressurised: it replaces
