Audi is presenting a new high-performance engine in the new Audi RS 4 Avant, one of the stars of the Frankfurt International Motor Show (IAA), and in the RS 5 Coupé. The 2.9 TFSI is a biturbo V6 brimming with immense power and an emotional sound, while delivering low fuel consumption.
The two turbos are located inside the engine V – an ideal solution for responsive power delivery.
With the newly developed 2.9 TFSI, Audi is creating a direct link to the legendary 2.7-liter V6 from the first RS 4 Avant. Produced from 1999 until 2001, it generated 280 kW (380 hp). Like the 2.7-liter engine, the new high-performance engine has been conceived as a biturbo. Compared with its direct predecessor, a naturally aspirated, high-revving V8, it enters a whole new dimension in terms of power, torque and efficiency. From 1,900 to 5,000 rpm, the 2.9 TFSI sends a mighty 600 Nm of torque through the crankshaft, marking an increase of 170 Nm. With its 331 kW (450 hp) – 155.5 hp per liter of displacement – it catapults the new RS 4 Avant from zero to 100 km/h in just 4.1 seconds. In the RS Dynamics package, Audi lifts the electronic top speed from 250 to 280 km/h.
The 2.9 TFSI is derived from the likewise new 3.0 TFSI. Due to the higher internal forces, its stroke has been shortened by 3.0 millimeters to 86.0 millimeters. With the bore remaining unchanged, the displacement is now 2,894 cm3. The crankcase incorporates thin-wall cylinder liners made from grey cast iron, while the diameter of the crankshaft main bearings has been enlarged by two millimeters. The crankcase is made from an aluminum-silicon alloy using a sophisticated sand-casting process and weighs just 34 kilograms. Its walls are of the so-called deep-skirt design – another weight-saving solution. The whole engine weighs in at just 182 kilograms, 31 kilograms less than its V8 predecessor. This benefits the overall weight and the axle load distribution of the new Audi RS 4 Avant.
seconds is the time it takes the new
Audi RS 4 Avant to sprint from 0 to 100 km/h.
|2.9-liter V6 TFSI engine in the Audi RS 4 Avant|
|FSI gasoline direct injection|
|Two turbochargers, one per cylinder bank|
|Continuous camshaft adjustment, Audi valvelift system|
|331 kW (450 hp) from 5,700 – 6,700 rpm|
|600 Nm from 1,900 – 5,000 rpm|
The two turbochargers on the 2.9 TFSI are dedicated to one cylinder bank each, with each one generating up to 1.5 bar of charge pressure. Just like all of Audi’s new V6 and V8 power units, the chargers are mounted in the 90-degree angle between the cylinder banks, meaning the exhaust is on the inside of the V and the intake is on the outside. This layout facilitates a compact design and short gas paths with minimal flow losses – the 2.9 TFSI reacts extremely spontaneously to the right pedal.
The high-performance V6 boasts compelling efficiency. It consumes just 8.8 liters of fuel per 100 kilometers in the NEDC (199 grams of CO2 per kilometer) – 17 percent less than in the preceding model. A key factor in this is Audi’s new TFSI combustion process, known as the B-cycle. Without restricting performance, it displays its strengths primarily under partial load, which is by far the most prevalent operating mode. In the area around the intake valves, it enables a geometry that, paired with the intake ports, generates targeted swirl of the gas charge. The common-rail system injects the fuel at up to 250 bar, whereby the high pressure ensures a homogenous spray pattern and even propagation of the flame front.
km/h is the max. speed for the new top-of-the-range
model with the optional RS Dynamic package.
Sheer power, delivered with high efficiency:
The 2.9 TFSI in the new Audi RS 4 Avant.
A further aspect in the efficiency of the 2.9 TFSI is the thermal management. Crankcase and cylinder head have separate cooling circuits. Following cold start, the adjustable water pump regulates the flow of coolant through the engine so that the oil warms up extremely quickly. The exhaust manifolds are integrated into the cylinder heads and are bathed in coolant, which aids the rapid warm-up. Once the engine is warm, this technology reduces the exhaust temperature and consumption decreases significantly as a result, especially during sporty driving.
The high efficiency of the V6 biturbo is also due in part to the low friction. Regulation of the oil pump, for instance, is fully variable, meaning it develops only as much pressure as is necessary. A new chain-drive concept reduces the power required – the balancer shaft is located deep inside the cylinder V and is driven by the crankshaft via a gear set. Chains run from here to the four camshaft gears, which have a slightly triangular shape to smooth out force spikes. The balancer shaft runs on extremely low-friction roller bearings.
The new 2.9 TFSI is also a highly emotional engine from an acoustic standpoint, with its distinctive sound evident from the moment it fires up. The flaps in the exhaust line open up under higher loads, generating an even richer, throatier sound. The Audi drive select handling system is fitted as standard and enables the driver to control the flaps – on both the standard RS exhaust system and the optional RS sports exhaust system with black end pipes. The induction system for the V6 biturbo has also been extensively optimized – pipes made from polished stainless steel allow the air to flow almost completely unobstructed.
hp is the output of the new V6 biturbo.
And it delivers 600 Nm at just 1,900 rpm.
Fuel consumption of the model named above:
Audi RS 4 Avant: Combined fuel consumption in l/100 km: 8.8 (26.7 US mpg)
Combined CO2 emissions in g/km: 200 – 199 (320.3)*
* Figures depend on the tire/wheel combination used.