This power unit already well-known within the range is now again making its appearance in the new-generation Audi A3: the 1.6-litre four-cylinder with variable intake manifold and overhead camshaft. With its engine block made of aluminium, this power unit is at least 13 kilos lighter than a grey cast-iron engine of the same size.
The cylinder head with valves operated by roller-type followers keeps internal friction to an absolute minimum. The other engine components are also optimised for minimum friction in the interest of enhanced fuel economy.
As a result of these highlights in technology, the new Audi A3 featuring the 1.6-litre power unit and five-speed manual gearbox consumes just 7.0 litres of premium fuel on 100 km in the composite mode, equal to 40.3 mpg Imp. And at the same time the A3 1.6 outperforms the EU 4 emission standard, giving the owner in Germany, for example, a tax bonus of EUR 306.
Despite this superior economy, the A3 1.6 is by all means a quick car: with engine output of 75 kW (102 bhp) and maximum torque of 148 Newton-metres or 109 lb-ft, the A3 1.6 accelerates to 100 km/h in 11.9 seconds and has a top speed of 185 km/h (115 mph). Offering equally good response and noise control, this highly advanced power unit certainly provides an ideal foundation for the Audi A3.
The A3 1.6 is available with either a five-speed manual gearbox or, at a later date, with six-speed tiptronic.
2.0 FSI four-cylinder
The new two-litre engine featured in the A3 is one of Audi's most advanced and sophisticated power units. The crankcase and basic engine dimensions are exactly the same as on the 96 kW (130 bhp) aluminium power unit already featured in the A4 and A6. The big difference, however, is that the FSI engine comes with direct petrol injection incorporating a common rail injection system and a single-piston high-pressure injection pump.
The cylinder head is a completely new development. The four valves per cylinder are actuated by low-friction roller cam followers. The intake camshaft can be continuously adjusted.
The 2.0 FSI in the A3 develops maximum output of 110 kW (150 bhp) and maximum torque of 200 Nm (147 lb-ft) at just 3500 rpm. With this kind of power, the A3 2.0 FSI with manual six-speed gearbox accelerates from 0-100 km/h in just 9.1 seconds and has a top speed of 211 km/h or 131 mph.
The FSI power unit is characterised, however, not only by its sporting performance, but also by outstanding efficiency: Considering the car's performance on the road, average fuel consumption of just 6.9 litres premium plus/100 km (in the composite cycle), equal to 40.9 mpg Imp, is more than impressive.
Thanks to a variable intake manifold and dual-branch front pipe, its torque curve sets new standards in this class. This progress has been made possible by the new air-guided combustion process of the 2.0 FSI engine. It allows stratified and homogeneous lean operation with excess air at part load.
Continuously adjustable flaps in each intake port together with the special shape of the piston crown ensure the optimum charge movement in the combustion chamber.
During stratified-charge operation, the FSI engine's most economical mode, fuel is not injected until the compression phase, and is then transported to the spark plug by the air turbulence produced in the combustion chamber. This causes an ignitable mixture to form around the spark plug, with a substantial air surplus in the rest of the combustion chamber.
At full load and at high part loads, the FSI engine also operates in the homogeneous mode.
The FSI engine needs three catalytic converters for efficient exhaust emission management: Two close-coupled three-way catalysts are accommodated in the manifold and there is an NOx storage catalyst on the underfloor of the car.
An NOx sensor controls and monitors the function of the storage catalyst. When the catalyst is saturated, the fuel/air mixture is briefly enriched to produce the requisite regeneration: the slightly richer exhaust gas causes the barium molecules to release the oxides of nitrogen, which are then discharged as nitrogen. This is a process the driver will not even notice.
The A3 2.0 FSI is available both with a six-speed manual gearbox and, at a later date, with six-speed tiptronic.
The 3.2-litre V6
The most powerful engine within the entire range and the most dynamic spark ignition power unit in the new A3 is the new V6 four-valve displacing 3.2 litres.
Through its outstanding torque and power characteristics, this six-cylinder is a particularly good match for the new, extremely dynamic second-generation Audi A3. Maximum output is 184 kW or 250 bhp and the torque range is particularly impressive, peaking at 320 Nm or 236 lb-ft between 2500 and 3000 rpm.
Clearly, this is just perfect for powerful pulling force at all speeds as well as fast, nimble acceleration - regardless of whether the driver opts for manual six-speed transmission or the new, very dynamic DSG Direct Shift Gearbox.
Performance on the road is truly outstanding: The A3 3.2 quattro accelerates from 0-100 km/h in just 6.5 seconds, top speed is 250 km/h or 155 mph, making this new six-cylinder the most sporting and dynamic A3 the world has ever seen.
With its cylinder angle of 150 the V6 is very compact, providing ideal conditions for crosswise integration of the engine transverse to the direction of travel. The valves are driven with minimum friction via roller-type followers with hydraulic compensation. The intake and outlet camshafts, in turn, are continuously adjustable in order to reduce emissions and enhance efficiency to an even higher standard.
Appropriate throttle butterfly control allows the engine to respond immediately and with supreme agility to the accelerator pedal. Indeed, particularly the interaction of the engine with ultra-fast and precise DSG control provides an entirely new feeling of power and performance on the road. And the perfect interplay of throttle butterfly and gearbox control becomes particularly clear by active throttle blips while shifting down in selector lever position S and in the manual gate.
Further highlights in technology such as the variable intake manifold and modified intake ducts further enhance the qualities of this six-cylinder in terms of torque, output and low emissions. Being redesigned for the A3, the engine also complies with the EU 4 standard.
The double-chamber exhaust system serves not only to reduce emissions, but also to provide the right kind of sound: If necessary, you can identify the most sporting A3 with your eyes closed, just by enjoying the throaty chortle of the engine. Indeed, Audi's acoustics specialists have created a very special sound in this case, which, without being unpleasant or even obtrusive in any way at all, is absolutely appropriate for the sporting potential of this very special power unit.
The A3 3.2 comes as standard with quattro permanent four-wheel drive and is available together with the six-speed manual gearbox. At a later point in time, the most sporting A3 may also be equipped with Audi's new DSG Direct Shift Gearbox.
1.9-litre TDI four-cylinder
One of Audi's most successful and popular engines is also to be found in the new A3: the four-cylinder 1.9-litre TDI with pump injector direct injection. Output of the current version is 77 kW (105 bhp), with maximum torque of no less than 250 Newton-metres or 184 lb-ft at just 1900 rpm.
The A3 1.9 takes just 11.4 seconds to accelerate to 100 km/h. And with its top speed of 187 km/h or 116 mph, the "basic" TDI is simply ideal for long stretches on the motorway at a high average speed - especially with its average fuel consumption of just about 5.1 litres/100 km or 55.4 mpg Imp not calling for a fuel stop until you have covered more than 1,000 kilometres.
This once again proves the superior maturity and all-round efficiency of TDI technology in conjunction with the pump-injector unit. Indeed, this system is still able to provide the highest level of injection pressure of up to 2,050 bar - the weight of a car on an area as small as a fingernail.
This high pressure ensures ultra-fine atomisation of fuel within the combustion chamber, thus providing excellent thermodynamic efficiency. On the road this means outstanding fuel economy and, at the same time, a high torque level. And thanks to fully controlled pre-injection, efficient sound control and emission management are two additional fortes of the pump-injector unit allowing the 1.9 TDI to easily outperform the EU 4 standard.
The A3 1.9 TDI comes in combination with a five-speed manual gearbox.
New 2.0 TDI four-cylinder
There can be no doubt about it: the newly developed 2.0-litre TDI featured for the first time by Audi in the A3 offers all the virtues of its smaller brother - high power output, superior fuel efficiency and low emissions.
Being the first TDI with a four-valve cylinder head, however, this new engine offers an even better interpretation of these qualities. Maximum output of 103 kW (140 bhp) and peak torque of 320 Nm (236 lb-ft) available all the way between 1750 and 2500 rpm make this the most powerful and dynamic four-cylinder diesel featured by Audi so far. Performance on the road is correspondingly impressive, the front-wheel-drive manual six-speed 2.0 TDI accelerating to 100 km/h in just 9.5 seconds and continuing up quickly to its top speed of 207 km/h or 128 mph.
Two other fortes of the new 2.0 TDI four-cylinder are low fuel consumption - 5.5 litres of diesel fuel/100 km (51.4 mpg Imp) in the composite cycle - as well as full compliance with the EU 4 emission standard.
In terms of engine construction, the new power unit stands out from its 1.9-litre "brother" not only by its larger capacity, but above all by the new cylinder head with four valves per cylinder. The crossflow cylinder head with two tangential intake ducts on either side and a twisted valve star ensures an optimum combination of fuel/air mixture tumble and cylinder charge.
Two overhead camshafts and low-friction roller-type followers with hydraulic valve control help to optimise the valve management process. The pump-injector units, in turn, are operated by roller-type rocking arms running on the exhaust camshaft.
The centrally positioned six-hole injection unit with flow-optimised injection jets and the central trough in the combustion chamber with new geometry interact with the recirculation of exhaust gas featuring integrated cooling in order to reduce emissions right from the start within the engine itself.
The pump injector has also been developed specifically for the new four-valve TDI. Compact dimensions and various measures of optimising the noise level in the injection and combustion process are just some of the new system's advantages.
Seeking to refine engine-running conditions, the development specialists focusing on the power unit have also worked carefully on the pistons, on the cylinder head reinforced at several points, and on the toothed belt guard.
A further innovation featured on the 2.0 TDI is the rapid-starting diesel system allowing the driver to start the engine immediately without a long preheating process under all climate conditions.
The A3 2.0 TDI comes with front-wheel drive in combination with Audi's six-speed manual gearbox. At a later point in time the top-of-the-range TDI will also be available with quattro drive and DSG Direct Shift Gearbox.
New DSG Direct Shift Gearbox
The revolutionary DSG Direct Shift Gearbox combines the advantages of a conventional six-speed manual gearbox with the qualities of modern automatic transmission, thus providing a drive concept superior in every respect. The driver benefits from supreme agility and driving pleasure combined with smooth, harmonious and dynamic acceleration without the slightest interruption of engine power. Further features are superior economy provided by good fuel efficiency and outstanding ease of control.
This new development is based on a three-shaft six-speed manual gearbox offering a high degree of variability in choosing the right transmission ratio. Featuring a twin multi-plate clutch with sophisticated electrohydraulic control, DSG is able to hold two gears in mesh at the same time.
How does DSG work? While driving, one gear is obviously always in mesh. Then, when approaching the next gearshift, the appropriate gear is preselected in advance with the clutch open or disengaged. When actually shifting gears, the clutch of the gear currently in mesh is disengaged and the other clutch engages at the same time with a certain overlap, allowing gears to shift under load with a permanent, ongoing flow of power.
Incorporating optimum gearshift strategies, the control logics integrated in the transmission housing provide an instantaneous, comfortable and smooth gearshift virtually free of any jolts or shudder.
And moving the gearshift lever in the manual lane or operating the paddles behind the steering wheel fitted as standard like in a racing car, the driver can actively influence the choice of gears and the gearshift point at any time.
Driving in the automatic mode, the driver can switch over to the particularly sporting S gearshift program with gears shifting up much later than usual, shifting down at an earlier point, and reducing gearshift times to a minimum. In automatic modes D and S, a tip-in function using the paddles on the steering wheel serves additionally to switch over to the manual gearshift mode for a certain, limited period.
Finished with a highly attractive and sophisticated aluminium surface, the gearshift gate follows the design of the tiptronic or multitronic gates so characteristic of the brand.
Apart from its high standard of efficiency and the ability to transmit high torque, the big advantage of this special kind of clutch is the various options it offers the driver when setting off. The driver is able to control the multi-plate clutch as he desires, varying from a particularly gentle acceleration process on slippery ground all the way to sporting, full-power acceleration, and with countless variants in between.
Gears are shifted spontaneously and crisply, as if the driver were just pressing a button. Electronically controlled throttle blip in the manual and S-modes adds to the special feeling of supreme dynamic performance.
DSG will be available on the two highest-torque versions of the Audi A3, the 3.2 quattro and 2.0 TDI.