Consequently, the Turbo Coupe's powerplant is a liquid-cooled, flat, or horizontally opposed, six- · cylinder with dual overhead c

Consequently, the Turbo Coupe's powerplant is a liquid-cooled, flat, or horizontally opposed, six- cylinder with dual overhead camshafts, four valves per cylinder, variable valve lift and timing, distributorless solid-state ignition, sequential electronic fuel injection and twin turbochargers. Proven dry-sump lubrication The engine consists of a split, pressure-cast, light-alloy crankcase. The block is made in usual Porsche fashion with camshaft housing, cylinder head and cylinder housings bolted to the crankcase. Based on decades of Porsche racing success, the engine's lubrication system is a dry sump design, with the oil carried in a remote reservoir. This configuration permits a more compact engine, critical for superb road holding. To ensure more than adequate engine lubrication, the Turbo Coupe has nine separate oil pumps. There are two oil extraction pumps for the turbochargers, two oil extraction pumps on each cylin- der head, and two oil extractions and one pressure pump in the crankcase. The extraction pumps ensure proper lubrication during long periods of hard braking. There are two oil coolers which transfer the heat from the engine oil to the engine coolant. The engine coolant itself releases its heat at three separate heat exchangers mounted in the front of the car. Radiators are mounted ahead of both front wheels in addition to one mounted in the car's nose. The crankshaft spins in eight main bearings. The six forged light-alloy pistons pump in Nikasil®- coated cylinder liners. The 3600 cc displacement engine is a highly responsive short-stroke design, with a cylinder bore of 100 mm (3.94 inches) and piston stroke of 76.4 mm (3.01 inches). There are four valves (two intake, two exhaust) per cylinder operated by dual overhead camshafts. Fuel injection is electronic and under the purview of the engine control module, as is the distributorless solid-state ignition system, which boasts individual coils for each cylinder. Two different camshaft profiles The engine control module also controls valve action via Porsche VarioCam Plus. This valve management system adjusts intake valve lift and timing based on engine speed and load. Though the VarioCam Plus operates far too quickly for the driver to be aware of it, the results are obvious. The effect is that of an engine with two different intake camshaft profiles, one set up for smooth and efficient around-town driving, the other a high-performance camshaft designed for higher speed. These two designs usually each preclude the other and most cars have a compromise of the two. Porsche VarioCam Plus removes the compromise and the driver benefits from the best of both driving worlds. Valve timing is controlled via a vane cell adjuster which continuously varies the two intake camshaft positions relative to crankshaft. The adjustment range covers a 40-degree range of crankshaft angle. Valve lift is varied by a system utilizing two cup tappets, one resting in the other. These tappets are actuated by separate cam lobes of differing size. The engine control module directs oil pressure to the appropriate tappet based on engine speed and load parameters. When non-pressurized, the tappet moves under the camshaft lobe, but exerts no pressure on the valve, in effect free wheeling.