The turbocharged 3.3 litre engine of the 1991 964 Turbo was largely carried forward from the 930/68 engine of the 1989 930 Turbo. A different turbocharger was used for the 964 along with a larger intercooler and a slight reduction in maximum boost pressure. The detailed specifications are below:
930/68 (930 Turbo)
M30/69 (964 Turbo)
M30/69S (X33)
M30/69SL (Turbo S)
Bore
97mm
97mm
97mm
97mm
Stroke
74.4mm
74.4mm
74.4mm
74.4mm
Displacement
3299cc
3299cc
3299cc
3299cc
Compression Ratio
7.0:1
7.0:1
7.0:1
7.0:1
Power (PS) @ RPM
300/5500
320/5750
355/5750
380/6000
Torque (Nm) @ RPM
430/4000
450/4500
471/5000
490/4800

During 1991/2 the 964 Turbo was offered with an optional performance pack - designated X33 - which involved the installation of the M30/69S engine as detailed above which consisted of polished and ported cylinder heads and more aggressive camshafts.

The 1992 Turbo S had even more aggressive camshafts fitted together with different fuel injectors and changes to the fan drive pulleys and deletion of the air conditioning system to reduce power losses.

 

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