3.6-Litre Turbocharged – The 996 Turbo Engine (2001)

The type 996 Porsche 911 Turbo was launched in the 2001 model year. The 996 Turbo was powered by a 3.6-litre, water-cooled, turbocharged engine featuring four valves per cylinder. This 3.6-litre power unit, known as the M96/70, comes from the Porsche 911 GT1 racing car, which helped Porsche clinch a one-two victory in the 24 Hours of Le Mans in 1998.

996 Turbo Engine

The six-cylinder boxer engine, boosted by the two exhaust gas turbochargers, develops maximum output of 309 kW (420 bhp) at 6,000 rpm. Its maximum torque of 560 Nm (413 lb-ft) starts at just 2,700 rpm and extends all the way to 4,600 rpm. The cylinders and cylinder heads are cooled by coolant extending from the hot to the cold side, ensuring a very consistent and homogeneous distribution of temperature. Heat discharged by the engine oil goes through an oil/water heat exchanger into the coolant.

As on the former model, the two turbochargers are arranged in parallel. The small volume of the intake manifold and the short exhaust manifolds ensure a good response. Flowing through a joint air cleaner housing, the intake air goes into the two compressors, from where the compressed air flows through two intercoolers in the wheel arches behind the rear wheels and on to one common duct upstream of the electronic gas pedal.

Reverse cooling of the compressed turbocharger air provides a good cylinder charge and keeps the temperatures of the various components to a minimum. The bypass valves are integrated into the turbine housings. Boost pressure is controlled by a joint stroke for the bypass valves masterminded by the engine management. The opening diameter depends on the charge pressure required and is around 1.80 bar at full load, reached at approximately 2,700 rpm. Boost pressure is controlled as engine speed increases, and is around 1.65 bar at maximum power.

VarioCam Plus

The cylinder charge is controlled by VarioCam Plus made up of four valves per cylinder, the axial camshaft adjusters, and the switchable valve tappets. The two intake and exhaust valves in each cylinder are arranged in V-configuration, at an inclined angle of 27.4°. To keep the moving masses in the valve gear as small as possible, valve shaft diameter is only 6 mm.

The intake and exhaust valves on the Porsche 911 Turbo feature dual valve springs closing the valves reliably even under the higher forces generated by the exhaust gas counter-pressure. VarioCam Plus valve lift adjustment consists of two changeover bucket tappets positioned within each other on the intake side of the engine and actuated by two cams of different size on the intake side camshaft of the engine. This serves to optimise engine output and torque, on the one hand, while reducing fuel consumption and exhaust emissions and improving motoring refinement, on the other.

3.6-Litre Turbocharged Technical Specifications

• Six-cylinder horizontally-opposed engine with aluminum crankcase and aluminum cylinder head
• Water-cooled
• Dry sump lubrication
• Four overhead camshafts
• Four valves per cylinder
• Axial camshaft adjustment
• Variable valve timing
• Valve lift control
• Hydraulic valve play compensation
• Two exhaust-driven turbochargers
• Two intercoolers
• Double-chamber exhaust system, each chamber with one three-way catalytic converter
• On-board diagnosis system
• Bore: 100 mm (3.94”)
• Stroke: 76.4 mm (3.01”)
• Capacity: 3600 cc
• Compression ratio: 9.4 : 1
• Engine output: 309 kW (420 bhp) at 6,000 rpm
• Max torque: 560 Nm (413 lb-ft) from 2,700-4,600 rpm
• Output per litre: 85.8 kW (116.7 bhp)
• Engine management: Motronic ME 7.8, knock control
• Max engine speed: 6,750 rpm
• Fuel grade: Premium plus (RON/MON 98/88), unleaded