The brand-new engine on the brand-new S3
The long-stroke 2.0 TFSI in the Audi S3 has been developed from scratch. The only thing it has in common with its predecessor, which was named Engine of the Year five times in a row between 2005 and 2009, is its displacement of 1,984 cc (bore x stroke 82.5 x 92.8 millimeters). The four-cylinder unit delivers a constant 380 Nm of torque to the crankshaft between 1,800 and 5,500 rpm. Rated power at 5,500 rpm is 221 kW , and the engine redlines at 6,800 rpm.
The S3 delivers impressive performance. The sprint from zero to 100 km/h is completed in 5.1 seconds when equipped with the S tronic (5.4 seconds with the manual transmission). The electronically governed top speed of 250 km/h (155.34 mph) is just a formality. The S3 with S tronic consumes on average just 6.9 liters of fuel per 100 km (manual: 7.0 liters). This corresponds to CO2 emissions 159 (162) grams per kilometer and for models equipped with the manual transmission, an improvement of 1.5 liters compared with the previous version.
The powerful four-cylinder engine features two balance shafts rotating at twice the speed of the crankshaft for tremendous smoothness. The sound is emotion-inspiring and sporty. An electromechanical sound actuator at the bulkhead brings the engine sound to life in the cabin. The exhaust system also includes a sound flap that opens at certain engine speed ranges to give the S3 a sportily sonorous sound.
The 2.0 TFSI boasts groundbreaking solutions in many fields of technology. One of these is the additional use of indirect injection. It supplements the FSI gasoline direct injection at part load to reduce consumption and particulate emissions. FSI injection, which works at pressures up to 200 bar, is used when starting and at higher loads.
The developers achieved new degrees of freedom when it comes to filling the combustion chambers. On the exhaust side, the Audi valvelift system varies the stroke of the valves in two stages; the camshaft on the intake side can be adjusted steplessly through 30 degrees of crankshaft angle while 60 degrees of adjustment is available on the exhaust side. The compression ratio of 9.3:1 is unusually high for a turbocharged engine.
The exhaust manifold is integrated into the cylinder head, where it is bathed in coolant. This solution lowers the temperature of the exhaust and accelerates warmup following a cold start, which lowers consumption during the cold-start phase. This concept also has a positive effect on fuel consumption during sporty driving because full-load enrichment is no longer necessary. The large turbocharger is also a new development. It achieves a maximum boost pressure of up to 1.2 bar for even more spontaneous engine response. A high-performance intercooler integrated into the water circuit greatly reduces the temperature of the compressed air and thus increases the amount of air required for combustion.
With the 2.0 TFSI’s innovative thermal management system, two rotary slide valves consolidated in a single module regulate the flow of coolant. These valves ensure that the engine oil heats up to its operating temperature soon after the vehicle is started; they also maintain the coolant temperature, as per a given driving situation, between 85 and 107 degrees Celsius (185.0° F and 224.6° F). As a result – regardless of load or engine speed – the valves always strike the perfect balance between minimal friction and high thermodynamic efficiency.
The 2.0 TFSI has been designed specifically for use in the new Audi S3. Pistons with stronger bolts and new rings plus reinforced connecting rods with new mounts transfer the power to the crankshaft. The gray cast iron crankcase has been reinforced at the main bearing seats and the main bearing cover.
The cylinder head is made of a new, particularly lightweight aluminum-silicon alloy characterized by high strength and temperature resistance.