2009 Audi A3

Powertrain

The Audi A3 and the A3 Sportback will be launched with eight powerful and efficient engines, six of which are state-of-the-art four-cylinder direct injection engines with turbocharging. Their abbreviations, TFSI and TDI, stand for the strengths of Audi engine technology – for performance and tractive power, for dynamics, smooth running characteristics and efficiency.

The range of power transmissions has been further expanded and is therefore even more attractive: Five of the eight engines leave the assembly line with standard six-speed transmissions. The high-tech S tronic transmission is available for all variants, in a new seven-speed version for certain variants. The quattro four-wheel drive system is available – in a further improved evolutionary stage – for five engines.

The five gasoline engines cover a wide range in terms of output. The entry-level assembly is the tried-and-tested 1.6-liter engine with aluminum crankcase and variable intake manifold. It has an output of 75 kW (102 hp) and offers 148 Nm (109.16 lb-ft) of torque at 3,800 rpm. This refined short-stroke engine actuates its valves with low friction via roller rocker fingers; a range of other components have been frictionally optimized to achieve low fuel consumption.

Agile performance: Result of lightweight design

In combination with the new seven-speed S tronic transmission, the three-door A3 sprints to 100 km/h (62.14 mph) in 11.7 seconds, continuing up to its top speed of 185 km/h (114.95 mph). This agile performance is also thanks to its low weight of just 1220 kg (2689.64 lb) – consistent lightweight design is one of the major strengths of the entire model range. The A3 1.6 consumes an average of 6.7 liters of fuel per 100 km (35.11 mpg). It is fitted with a five-speed manual transmission as standard, and is driven via the front wheels.

At the other end of the gasoline engine range is the V6 with a displacement of 3189 cm3. It offers maximum torque of 320 Nm (236.02 lb-ft), which is available between 2,500 and 3,000 rpm, and output of 184 kW (250 hp). The particular characteristic of this long-stroke engine is its extremely low cylinder angle of just 15 degrees – enabling it to be fitted with two camshafts. Both can be continuously adjusted, by 52 degrees on the intake side and 42 degrees on the exhaust side. The 3.2-liter V6 is a high-torque, sonorous and free-revving engine. It accelerates the A3 from 0 to 100 km/h (62.14 mph) in 6.1 seconds. Its top speed is 250 km/h (155.34 mph) (governed), with average consumption of 9.4 liters per 100 km (25.02 mpg). The V6 is always coupled to the six-speed S tronic and quattro fourwheel drive.

TFSI: Superior engine technology

The three medium-sized gasoline engines in the A3 and in the A3 Sportback are four-cylinder TFSI engines – with which Audi is again demonstrating its leading position in engine construction. They ideally combine the superior technology of FSI gasoline direct injection with charging via a turbocharger.

In direct injection, the fuel is injected directly into the combustion chambers at high pressure; valves in the intake tract specifically cause it to swirl together with the air blown in by the turbocharger. Fuel evaporation lowers the temperatures, solving the old, basic problem of all turbocharged engines – high heat development and the tendency to knock. Despite charging, the engineers have succeeded in providing these engines with high compression, making a vital contribution towards highly efficient combustion.

The smallest TFSI engine is a perfect example of another of Audi’s successful efficiency strategies – downsizing, which replaces displacement via charging. This short-stroke engine has a displacement of just 1,390 cm3, but offers an impressive torque of 200 Nm (147.51 lb-ft), which is additionally available over a wide engine speed range from 1,500 to 4,000 rpm. 80 percent of this torque are practically available as of idle speed, at 1,250 rpm – a top value in this class. The 1.4 TFSI also sets standards with its smooth running and pleasant sound profile.

The small four-cylinder engine, which always drives the front wheels, offers impressively agile performance, particularly when the vehicle is fitted with the seven-speed S tronic instead of the six-speed manual transmission. With this, the three-door Audi A3 1.4 TFSI sprints from 0 to 100 km/h (62.14 mph) in just 9.3 seconds, continuing up to 203 km/h (126.14 mph). However, its average consumption is a mere 5.6 liters/100 km – the equivalent of only 133 grams of CO2 per kilometer (214.04 g/mile).

The next largest turbocharged gasoline engine, the 1.8 TFSI, also combines all of the features of cutting-edge engine technology. It is very light, weighing just 135 kg (297.62 lb). One intake camshaft, which can be adjusted by a crank angle of 60 degrees, improves combustion chamber filling; two balancer shafts compensate the second-order inertia forces, thereby ensuring highly cultivated running. With its volumetric flow regulation and two-stage pressure control, the oil pump reduces fuel consumption by 0.2 liters per 100 km. Complex fine-tuning on the pistons, the cylinder bores and the crankshaft bearings reduces internal friction.

The water-cooled turbocharger is designed for a spontaneous response – at an engine speed of 2,000 rpm, the engine only requires 1.2 seconds to offer its maximum torque. The four-cylinder engine is spontaneous, fleet-footed, freerevving and high-torque. From its displacement of 1,798 cm3, it generates a similar amount of power as a naturally aspirated V6 engine a few years ago: It offers an output of 118 kW (160 hp), with a high maximum torque of 250 Nm (184.39 lb-ft) from 1,500 to 4,200 rpm.

Its performance is accordingly superior: 0 – 100 km/h (62.14 mph) in 7.5 seconds, top speed of 220 km/h (136.70 mph) – with an average consumption of just 6.6 liters/100 km (35.64 mpg). These values apply to the three-door vehicle with front-wheel drive and seven-speed S tronic. A six-speed manual transmission is fitted as standard. The A3 1.8 TFSI can also be optionally fitted with quattro drive.

Subscription to victory: The 2.0 TFSI

The most powerful four-cylinder engine fitted in the A3 family is the 2.0 TFSI. Technically related to the 1.8 TFSI, it is a particularly successful model: Since 2005, an international jury comprised of journalists has voted it "Engine of the Year" four years in a row. The two-liter engine also operates with an adjustable intake camshaft and two balancer shafts. Audi has given it a high compression of 10.5:1, previously reserved for sporty naturally aspirated engines; thanks to this, thermodynamic efficiency is improved still further.

The four-valve engine has a displacement of 1,984 cm3; it combines superior tractive power with high peak output. In the manner of a powerful diesel engine, it transmits 280 Nm (206.52 lb-ft) onto the crankshaft at just 1,700 rpm; this maximum torque is constantly available up to 5,000 rpm. Its output peaks at 147 kW (200 hp).

The 2.0 TFSI engine accomplishes all of its tasks with absolute ease. Together with the six-speed S tronic, which is optionally available in addition to the sevenspeed manual transmission, it accelerates the front-wheel-drive three-door A3 to
100 km/h (62.14 mph) in 6.8 seconds, reaching a top speed of 238 km/h (147.88 mph). An average of 7.0 liters of fuel/100 km (33.60 mpg) suffices. Optionally, the A3 2.0 TFSI also leaves the assembly line with the high-tech powertrain combination of S tronic and quattro.

TDI: The modern embodiment of sportiness

Audi’s TDI engines also set the standards amongst the competition. The brand with the four rings introduced this technology back in 1989, and has been gradually extending its lead ever since. The Audi diesel engines are the modern, smart embodiment of sportiness – the two Le Mans victories celebrated by the R10 TDI racing car in 2006 and 2007 demonstrated the power offered by the TDI engine. In the three four-cylinder engines which Audi fits in the A3 and A3 Sportback, high outputs, high torques, low consumption values and refined running come together to form a rounded overall picture.

The 1.9 TDI is a modern classic – high-torque, powerful and extremely efficient. The two-valve engine with its displacement of 1,896 cm3, which is supplied by a unit injector, has an output of 77 kW (105 hp) and transmits 250 Nm (184.39 lb-ft) of torque onto the crankshaft at just 1,900 rpm. As in the case of all Audi TDI engines, its exhaust gas is cleaned in a particulate filter. The 1.9-liter engine is available in both the conventional variants of the A3 and A3 Sportback and in the particularly economical e models.

It always drives the front wheels; a five-speed transmission is fitted as standard, whilst the six-speed S tronic is available as an option (not in the e model). The three-door A3 and the A3 Sportback 1.9 TDI e consume just 4.5 liters of diesel per 100 km (52.27 mpg) – corresponding to CO2 output of 119 g/km (191.51 g/mile) and a range of over 1200 km (745.65 miles) with one tank of fuel. In the e models, the engine electronics are specifically and extensively coordinated to achieve low consumption. A longer gear ratio for gears three to five, rolling resistance-optimized tires and specific fine-tuning measures on the body help to achieve this high efficiency. Typically of Audi, driving pleasure does not suffer as a result – quite the opposite: With a top speed of 194 km/h (120.54 mph), the three-door A3 1.9 TDI e is actually 7 km/h (4.35 mph) faster than the entry-level version. Acceleration from 0 to 100 km/h (62.14 mph) remains the same at 11.4 seconds.

The intensively redeveloped four-cylinder TDI engine, which has a displacement of 1968 cm3, builds on the characteristic strengths – driving pleasure, economy and smooth running characteristics – of its predecessor, the most frequently built diesel engine in the world. The piston geometry has been modified. Two balancer shafts further reduce vibrations. The toothed belt drive has additionally been redeveloped in terms of acoustics. The turbocharger is also of a new generation; it operates with adjustable guide vanes to build up torque rapidly. Electric motors control the position of the swirl flaps in the intake manifold to adapt the inflowing air to the load and engine speed.

Smoother running characteristics: Common rail injection

Important progress has also been achieved in the injection system: A common rail system has replaced the previously implemented unit injectors. The rapidly switching piezo injectors, with their eight-hole nozzles, are able to inject fuel up
to five times per working cycle – this precise modulation audibly reduces the noise level. The system pressure of 1,800 bar equates to extremely fine fuel atomization and efficient combustion.

This combined progress leads to a high maximum engine speed of 5,000 rpm and improved thermodynamics in the combustion chambers. These enable the 2.0 TDI to be operated with up to 60 percent recirculated and cooled exhaust gas, significantly reducing untreated nitrogen oxide emissions.

Audi is equipping the A3 model series with two versions of the further developed 2.0 TDI engine, generating 103 kW (140 hp) and 125 kW (170 hp). Both can be combined with three drive variants – front-wheel drive with six-speed manual transmission, front-wheel drive with six-speed S tronic or quattro with manual transmission.

In the 103 kW (140 hp) version, the two-liter engine provides torque of 320 Nm (236.02 lb-ft), which is available from 1,750 to 2,500 rpm. With 8.9 seconds for the standard sprint and a top speed of 207 km/h (128.62 mph) (three-door version with front-wheel drive and S tronic), the diesel engine offers sporty performance. It consumes an average of 5.1 liters of fuel/100 km (46.12 mpg).

In the more powerful version, the 2.0 TDI offers an impressive 350 Nm (258.15 lb-ft) of torque from 1750 to 2500 rpm. The three-door version with frontwheel drive and S tronic reveals dynamic key values of 7.8 seconds for the standard sprint and a top speed of 222 km/h (128.62 mph). In view of this performance, its low standard consumption of just 5.6 liters/100 km (42.00 mpg) is particularly impressive.

High-tech from Audi: Power transmission

Front-wheel or four-wheel drive, manual transmission or S tronic – in the A3 family, Audi offers a range of power transmission systems unlike any other competitor in the premium compact class. The six-speed manual transmissions, which are fitted as standard with all engines except the 1.6, the 1.9 TDI and the 3.2 engines, have particularly light magnesium housings. They can be shifted precisely and smoothly over short distances, and are extremely efficient.

One of the highlights which lends the A3 and the A3 Sportback their exceptional position amongst the competition is the optional S tronic (standard in the 3.2 quattro). Audi’s dual-clutch transmission combines the comfort of an automatic transmission with torque converter with the dynamics and efficiency of a manual transmission.

The driver can control it manually via a one-touch lever or with paddles on the steering wheel. Two fully automatic operating modes are additionally available – D for Drive and S for Sport. In N mode, the transmission management system ensures that the engine runs at low speed whenever possible, in order to save fuel. The extremely compact S tronic is able to change its gears at lightening speed without any interruption in tractive power. The so-called mechatronics – a block consisting of the central processor and the hydraulic actuator complex – control its operation. Two gear train halves are integrated into the S tronic housing; the first consists of the gear set for the odd gears, the second of the gear set for the even gears. The two clutches are positioned in series; they operate two input shafts on a common axle. Clutch 1 is connected to a full shaft, which acts on gear train half 1, clutch 2 to a hollow shaft, which encapsulates the full shaft and operates gear train half 2.

The two gear train halves are permanently active, but only one is frictionally connected to the engine. When, for example, the driver accelerates in third gear, which lies in the first gear train half, the fourth gear is already engaged in the second gear train half. Shifting gears takes place by switching clutches – whilst clutch 1 opens, clutch 2 closes. This process is so smooth and comfortable that the driver barely notices it. It takes only a few hundredths of a second and is carried out with no noticeable interruption in tractive power.

Completely new: S tronic with seven gears

Audi fits two different versions of the S tronic system in the A3 and the A3 Sportback. The familiar six-speed version, which is able to cope with high torques, is installed in the 2.0 TFSI, the 3.2 quattro and the TDI engines. For the 1.6, the 1.4 TFSI and the 1.8 TFSI engines, a newly developed, particularly lightweight seven-speed assembly has been implemented. Unlike the six-speed S tronic, its two clutches are dry. Discontinuation of the oil supply offers progress which further enhances the transmission’s already high efficiency. A further solution helps to attain low fuel consumption: Six of the seven gears are short and sporty, whereas the seventh reduces the engine’s speed thanks to its relatively long ratio.

Further technology which is superior to that of the competition, and which Audi offers in the A3 model line, is the quattro four-wheel-drive system. It is optionally available for the four-cylinder TFSI (as of 118 kW/160 hp) and the two 2.0 TDI engines; it is fitted as standard with the six-cylinder 3.2-liter engine. The quattro drive provides the A3 and the A3 Sportback with a vital advantage under all conditions, both in summer and in the winter – the high, additional grip, slip-free acceleration, vehicle dynamics, stability and straight-line stability make the difference.

The core element of the quattro drive is an electronically controlled multi-plate clutch. It is mounted at the end of the propshaft in the rear end – a location which improves the distribution of weight in the vehicle. Under normal driving conditions, the clutch transmits the engine’s power to the front wheels; when required – i.e. when the front wheels move onto a slippery surface – it diverts this power continuously to the rear wheels. On switching over, the plates in the interior of the clutch are compressed by means of high oil pressure. A new pressure reservoir for the pump now makes this process even faster – it only takes a few milliseconds.

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