Offering immense power and extremely good engine response – the further developed 5.2 FSI in the new R8* is a high-powered engine that was systematically designed for high engine speeds. As soon as the engine is started, it revs at 2,500 rpm for fractions of a second. Under load, the naturally-aspirated ten-cylinder engine develops a very unique sound – a throaty hissing and roaring.
Audi offers the V10 with 5,204 cc of displacement in two versions. On the R8 V10, the long-stroke engine (bore x stroke: 84.5 x 92.8 mm (3.3 x 3.7 in)) has a power output of 397 kW (540 hp) at 8,250 rpm, and its maximum torque of 540 Nm (398.3 lb‑ft) is available at 6,500 rpm. For the R8 V10 plus, these values are 440 kW (610 hp) and 560 Nm (413.0 lb‑ft) at the same engine speeds. At both power levels, the 5.2 FSI can rev up to 8,700 rpm – at limited speed, the pistons travel a total of 26.9 meters (88.3 ft) per second.
In the new Audi R8 V10 plus, the engine’s specific power is 117.2 hp per liter displacement. Each horsepower only needs to move 2.38 kg (5.2 lb) of weight, because the high-performance sports car only weighs 1,454 kg (3,205.5 lb) (dry weight). This leads to impressive performance figures: The fastest production Audi ever catapults from 0 to 100 km/h (62.1 mph) in 3.2 seconds and from 0 to 200 km/h (124.3 mph) in 9.9 seconds. It can continue accelerating to a maximum speed of 330 km/h (205.1 mph). The new Audi R8 V10 accelerates from 0 to 100 km/h (62.1 mph) in 3.5 seconds and has a top speed of 320 km/h (198.8 mph).
Compact powerplant: the V10
The V10, which is produced at the engine plant in Győr, Hungary, in part by manual assembly, is very compact. Its low mounting position in the car results in a low center of gravity. The offset between cylinder banks is 18.5 mm (0.7 in). The cylinder firing sequence is 1 – 6 – 5 – 10 – 2 – 7 – 3 – 8 – 4 – 9.
The crankshaft is designed as a common pin shaft. The connecting rods of opposing pistons are joined to a common crank pin, which results in alternating firing intervals of 54 and 90 degrees. This rhythm makes a big contribution toward producing a very unique, motorsport-like sound. Two flaps in the exhaust system let the driver choose between a comfort-oriented sound and a sporty sound. The entire sound stage is authentic – including the babbling sound when the foot is taken off the accelerator pedal and a more roaring sound when shifting gears under full load.
The cylinder crankcase of the 5.2 FSI is manufactured in a complex low-pressure die-casting process with a high-tech aluminum alloy that combines low weight and high strength. The cylinder liners are honed from the solid piece by exposing the hard silicon crystals. The bed plate construction of the crankcase gives it maximum rigidity, and gray cast iron bearing brackets reduce heat expansion and thereby improve bearing play. The forged crankshaft and the connecting rods that are made of forged steel combine high strength and low weight, and the pistons are forged from an aluminum alloy.
Reliable under all conditions: dry sump lubrication
The motor oil, which is temperature-controlled in a dedicated cooler, comes from a dry sump – a principle borrowed from car racing. This makes it possible to mount the engine extremely low. The pump module, which operates with multiple suction stages, assures proper lubrication under all conditions – including during lateral accelerations of around 1.5 g, which are possible in the new R8.
The camshafts are chain driven, and they operate on the rear side of the engine. All four camshafts can be adjusted by up to 42 degrees crank angle. This enables a broad range of valve timing for the 40 valves that are actuated by roller cam followers. The exhaust valves are sodium filled for better cooling.
Compared to the previous engine, Audi has configured the V10 for even more spontaneous high power output. The compression ratio grew from 12.5:1 to 12.7:1, valve timing was configured for good chamber filling at high engine speeds, and the intake channels were optimized in the lightweight variable intake manifold. The machined inlet ducts and the valve shaft diameter of just 4.8 mm (0.2 in) also contribute to optimal flow into the cylinder.
These extraordinary efforts have led to convincing results: The 5.2 FSI revs just as spontaneously, and even reaches high revs a bit quicker than the best short-stroke engines on the global market. One indicator of this is the jump to full-load, which describes the engine’s spontaneous throttle response. This means that as soon as the driver presses the accelerator pedal fully while idling in the stationary car, full load is already available after 6.6 tenths of a second – this is nearly 20 percent faster than in the previous engine. This means that the driver can apply measured acceleration ideally during a sporty style of driving – whether on the race track, during a controlled drift or on snow.
New combustion process: FSI plus MPI
Dethrottling of the air induction system goes hand in hand with a new combustion process. Along with direct injection into the combustion chambers (FSI), the V10 adds fuel injection into the induction manifold (MPI). Two newly developed control units operating by the master-slave concept are at work: each handles part of the large amount of computing work, and together they control the dual injection process.
In the lower part-load range, only MPI injection is used. The high vacuum pressure in the induction manifold vaporizes the fuel very well, which leads to clean combustion. In the moderate load range, induction manifold and direct injection are used in equal measures. In the full-load range, the FSI system, which builds up a pressure as high as 200 bar, performs around 85 percent of the injection. The directly injected fuel swirls intensively, cooling the walls of the combustion chambers, which reduces the tendency to knock. The remaining MPI share contributes to a high charge concentration and to a boost in power.
High efficiency gain: CO2 is 33 g/m (53.1 g/mi) lower
Despite its highly dynamic character, the new Audi R8 consumes far less fuel than the previous model. Its V10 version had a combined NEDC fuel consumption of 13.1 liters per 100 km (18.0 US mpg) (equates to 305 g/km (490.8 g/mi) CO2) – while it is now just 11.4 liters per 100 km (20.6 US mpg) (272 g/km (437.7 g/mi) CO2), which represents a 13 percent reduction. In the case of the V10 plus, fuel consumption was reduced from 12.9 liters/100 km (18.2 US mpg) (299 g/km (481.2 g/mi) CO2) to 12.3 liters per 100 km (19.1 US mpg) (287 g/km (461.9 g/mi) CO2).
The new cylinder-on-demand (COD) technology makes a substantial contribution toward this efficiency gain. Under low to intermediate load conditions – when one of the four upper gears is engaged – it shuts down the cylinders of the left or right bank by deactivating their injection and ignition processes.
If the deactivation phase lasts longer than 30 to 60 seconds, the COD system reactivates the bank to prevent cooling of the catalytic converter, and it deactivates the other cylinder bank. During a long COD phase, it continually alternates back and forth between the two banks. The driver does not perceive this at all. The control unit smooths the transitions, each of which takes around three-tenths of a second, by shutting off the cylinders of each bank sequentially.
Along with the COD system, the 5.2 FSI in the new Audi R8 has other efficiency technologies on-board as well. When the comfort mode of the Audi drive select dynamic driving system is active, and the vehicle speed is under 55 km/h (34.2 mph), the seven-speed S tronic switches over to freewheeling operation when the driver releases the accelerator pedal. It disengages both clutches, and the high-performance sports car coasts. Just before stopping, the start-stop system shuts the engine off entirely; the subsequent engine restart is performed gently.
The equipment and data specified in this document refer to the model range offered in Germany. Subject to change without notice; errors and omissions excepted.