This is the first on series of posts that will cover every detail of another stunning and high performance Audi vehicle.
Audi is adding another model to its R8 high-performance sports car lineup: Hot on the heels of the R8 Spyder 5.2 FSI quattro comes another model with a V8 engine. The 4.2-liter FSI produces 430 hp and launches the open-top two-seater to 62.14 mph in 4.8 seconds on its way to a top speed of 185.79 mph. The engine is mated to the R tronic sequential manual gearbox; quattro permanent all-wheel drive is standard.
The R8 Spyder 4.2 FSI quattro has a lightweight cloth top with a fully automatic drive. Its body is an aluminum Audi Space Frame with large-area components of carbon fiber composite material. A fit and finish typical of Audi, excellent everyday practicality and optional high-end technologies – from LED headlights to seatbelt microphone – complete the profile of the model athlete.
Superior power: the engine
The free-breathing 4.2 FSI is a high-performance engine such as can be found in racing. It delivers an experience that enthralls all of the senses – with spontaneous, voracious throttle response, with its easy revving, with hefty torque, prodigious power and sonorous, voluminous music.
The V8 accelerates the R8 Spyder from zero to 100 km/h (62.14 mph) in 4.8 seconds and on up to a top speed of 299 km/h (185.79 mph). Both values apply for the manual transmission and for the R tronic. At Audi, dynamics also always means efficiency. The R8 Spyder 4.2 FSI quattro with the R tronic consumes on average 13.9 liters of fuel per 100 km (16.92 US mpg); fuel consumption with the manual transmission is 14.9 liters per 100 km (15.79 US mpg). A recuperation system that recovers energy during braking is standard. The forced oil pump of the dry sump lubrication system features various suction and discharge stages for load-dependent operation.
The 4.2 FSI, which is also used in this form in the R8 Coupé, produces 316 kW (430 hp) from a displacement of 4,163 cc – 73.5 kW (103.2 hp) per liter. At the nominal engine speed of 7,900 rpm, the long-stroke (bore x stroke 84.5 x 92.8 millimeters [3.33 x 3.65 in]) engine’s eight pistons travel 24.1 meters (79 ft) each second. The electronic rev limiter kicks in at 8,250 rpm. The V8 delivers 430 Nm (317.15 lb-ft) of torque to the crankshaft between 4,500 and 6,000 rpm, with at least 90 percent of peak torque available between 3,500 and 7,500 rpm.
The compact V8, which is hand-assembled at the engine factory in Györ, Hungary, has the classic cylinder angle of 90 degrees and weighs just 216 kilograms (476 lb). Its crankcase is made of an aluminum-silicon alloy using the low-pressure die casting method, which ensures particular homogeneity. The high silicon content makes the cylinder barrels extremely resistant to wear.
A bedplate structure gives the crankcase its high rigidity and optimal vibration behavior. The cast iron bearing bridges reduce its thermal expansion and thus keep the play at the main bearings of the crankshaft within tight limits. The forged crankshaft, the forged steel connecting rods and the forged aluminum pistons are extremely lightweight, yet strong. The dry sump lubrication system with its separate oil tank enables the engine to be installed very low while also ensuring the supply of oil to the engine even under extreme lateral acceleration.
The high-revving V8 FSI draws its fuel from an FSI gasoline direct injection system – typically Audi. The common rail unit injects the fuel at up to 120 bars of pressure. The fuel mixture is swirled intensely in the combustion chambers and thus cools the walls. This allows a high compression of 12.5:1, for increased performance and efficiency. The 32 valves are actuated via roller cam followers by four camshafts, each of which can be moved through 42 degrees of crankshaft rotation. They and the ancillaries are driven by zero-maintenance chains running on the back side of the engine.
The 4.2 FSI breathes through straight aluminum velocity stacks 23 centimeters (9.06 in) in length integrated into the dual intake system. The intake plenum is made of lightweight plastic. Vacuum-actuated flaps controlled by the engine management system are integrated into the intake ports. They cause the air to move with a roller-like rotation (to “tumble”), which increases the efficiency of the combustion process.
The dual-branch exhaust system features dual tailpipes. The exhaust system components and the pipes of the manifold have been designed for low backpressure and are very light. The exhaust flaps in both tailpipes open at higher load and engine speed for an even fuller sound.
