What advantage did the Bf 109E's Bosch fuel injection pump give it?

The Bf 109E's DB 601 fed fuel by injection, which proved especially useful against the British Supermarine Spitfire and Hawker Hurricane, whose gravity-fed carburettor engines cut out when subjected to negative g forces — something that never happened to the DB 601. In aerobatic manoeuvres, the DB 601 kept its performance where early carburettor engines, such as the British Rolls-Royce Merlin, lost power because the carburettor float chamber ran dry of fuel. For take-off, the engine delivered 1,175 PS (1,159 hp; 864 kW) at 2,500 rpm.

The Bf 109s thus had the initial advantage in dives, both attacking and escaping, because they could pitch straight down without losing power.

The Bf 109Es used as escorts during the battle had limited fuel capacity, with a maximum range of 660 km (410 miles) on internal fuel alone. On reaching a British target they had barely 10 minutes of flight left before turning for home.