1995: Bi-turbocharging

The 993 series 911 Turbo, presented in 1995, was given a 3.6-litre engine fitted with two small turbochargers. The engine’s performance curve was not dissimilar to a high-displacement naturally aspirated engine. From as low as 2,000 rpm, the engine generated plenty of thrust which changed into impressive, rousing velocity as of 3,500 rpm, pressing the occupants into their seats. In addition to the output that increased to 300 kW (408 hp) and the rise in the maximum torque to 540 Newton metres, the Weissach engineers also aimed to reduce the engine’s acceleration turbo lag to a previously unknown minimum. They achieved this by using two small turbochargers instead of one large one, whereby the low moment of inertia of the smaller blades had the most significant effect. The two regulated turbines with integrated bypass flap generated a boost pressure of 0.8 bar. The impressive increase in output and engine speed was also due to optimisation of the charge cycle, the high level of efficiency of the two charge-air coolers and the knock control system that facilitated running the engine at optimum efficiency.