2010 Audi TT RS Roadster
Taking dynamics to a whole new dimension
Audi is once again building a five-cylinder – a very special one: Arriving at dealerships this summer, the TT RS has a turbocharged 2.5-liter engine with FSI direct gasoline injection; it produces 250 kW (340 hp) and 450 Nm (332 lb-ft) of torque. The potent five-cylinder engine provides outstanding performance. In conjunction with quattro permanent all-wheel drive and a high-performance chassis, the engine makes the compact Audi TT RS a top- notch sports car – available in Coupé and Roadster versions.
The Audi TT RS is the first classic sports car in the RS family. Like the RS 4 and the RS 6, the Audi TT RS was developed by quattro GmbH. Its key data are outstanding: 4.6 seconds for the sprint from zero to 100 km/h (62 mph) (for the Coupé) and 15.9 seconds from zero to 200 km/h (124 mph) on the way to an optional top speed of 280 km/h (174 mph) – the TT RS is the fastest production sports car in the compact class. And it is a purist driving machine – powerful, lightweight, efficient, conceived and implemented without compromise.
The 2.5-liter TFSI five-cylinder unit has two faces. When driven with restraint, the turbo conveys the composure that comes from having 450 Nm (332 lb-ft) of torque available in practically any situation – from the bottom of the torque curve almost to the very top, from 1,600 to 5,300 rpm. With this tremendous pulling power, the TT RS overtakes with casual ease.
When the driver pushes the five-cylinder he or she experiences its other side – the raw power of 250 kW (340 hp); the skin-tingling music as the engine revs enthusiastically up to 6,800 rpm; the unmistakable, throaty roar is the classic five- cylinder sound from Audi. A glance under the hood reveals the engine in all its glory, with no engine cover – an impressive piece of technology.
Winding rural routes or a few laps around a racetrack allow the superior handling to shine. The TT RS turns spontaneously, almost greedily, into curves and passes through them with aplomb, precisely guided by its responsive steering. As the car approaches its very high limits, it begins to understeer ever so slightly. This effortless controllability is another character trait of the compact driving machine from Audi.
As the car exits the curve, the quattro technology safely transfers the tremendous power to the road in situations where competitor vehicles with their two powered wheels struggle to find grip. All of these strengths and the stirring power of the engine make the TT RS the epitome of pure, essential dynamism.
Turbocharged gasoline engines are a traditional Audi domain, and the five- cylinder turbo in the Audi TT RS is a high-performance engine. With a displacement of 2,480 cubic centimeters, it produces 250 kW (340 hp) between 5,400 and 6,500 rpm. Peak torque of 450 Nm (332 lb-ft) is already available at 1,600 rpm and remains constant up to 5,300 rpm.
The basic concept makes an Audi five-cylinder unit an unusual engine. It has a firing interval of 144 degrees and a firing order of 1-2-4-5-3, alternately between directly adjacent cylinders and cylinders that are far apart. This produces the distinctive rhythm and musical sound, which are also the result of the intake and exhaust geometry. A specially designed torsional vibration damper at the front end of the crankshaft compensates for the free moments of the engine.
The 2.5-liter TFSI is extremely compact. Its cylinder spacing measures 88 millimeters (3.5 in); the external main bearings were moved inside. Only 494 millimeters (19.5 in) long, the long-stroke engine (bore x stroke 82.5 x 92.8 millimeters (3.3 x 3.7 in)) is suitable for transverse installation in the TT RS.
Its low weight of only 183 kilograms (403.45 lb) is also a top figure. It helps keep the total weight of the TT RS low and also offers significant advantages for the distribution of axle loads and thus for the car’s handling.
The crankcase is made of vermicular graphite cast iron. This high-tech material that made its name in the large TDI engines combines the ultimate in rigidity with low weight. Audi is the first automaker to use this material for a gasoline engine. Targeted reinforcements on the main bearing seat and the main bearing cover further increase the load-bearing capacity of the block.
The pistons are made of cast aluminum; each of them together with the rings and pins weighs only 492 grams (1.1 lb). Just like the forged connecting rods, they are designed to withstand the highest of loads; systematically minimized asymmetries and slightly angled box walls enhance their strength. Sodium-cooled exhaust valves and hardened valve seat rings are used in the cylinder head, which is cast from a high hot-strength aluminum alloy.
TFSI – the winning technology from Le Mans
The powerful five-cylinder engine is surprisingly frugal, requiring an average of just 9.2 liters/100 km (25.57 US mpg) in the Coupé (Roadster: 9.5 l/100 km
(24.76 US mpg)). Its high efficiency can be attributed to the combination of FSI direct fuel injection and turbocharging, two of Audi’s core technologies. This TFSI pairing harmonizes perfectly in motorsports, the world’s most demanding test ground: It has powered the R8 race car to five victories in the 24 Hours of Le Mans and 63 victories in 80 other races. Loads are measured for the injection unit’s controller by means of a pressure sensor in the intake manifold – a particularly precise method of measurement. Pneumatically actuated flaps generate a controlled rotation of the inflowing air in the combustion chamber. The common rail unit injects the gasoline into this roller-shaped “tumble” at a pressure of 120 bar. The fuel is intensely swirled in the combustion chamber and cools the walls, solving a long-standing problem of turbo technology: the risk of knock during combustion. TFSI technology enables a high 10.0:1 compression ratio and correspondingly good efficiency.
The two camshafts also do their part to ensure that the combustion chamber is well filled: They can be hydraulically moved through 42 degrees of crankshaft rotation. They are driven by a two-stage chain drive comprising a particularly quiet sprocket chain, a roller chain and an intermediate timing gear.
The turbocharger is large, with its compressor wheel measuring 64 millimeters in diameter at the outlet. It can theoretically compress 335 liters (11.83 cu ft) of air at full load; the relative boost pressure can be up to 1.2 bar. The turbocharger casing has a separate oil supply and a cooling system serviced by a separate water pump. At full load, the intercooler reduces the temperature of the compressed air and achieves an efficiency of more than 80 percent. The entire admission tract has been optimized for minimal pressure loss and the development engineers succeeded in reducing the exhaust backpressure in the dual exhaust tract.
There is a flap in the left tailpipe. When it is closed, the exhaust is rerouted through the rear muffler and exits through the right tailpipe. The flap opens when accelerating at higher loads and engine speeds. The exhaust now takes the direct route to the outside, producing a fuller, more intense sound.
The driver can open and close the flap as desired by pressing the standard Sport button on the center tunnel, which also makes the engine response more direct or more comfortable. Audi also offers an optional sports exhaust system with black tailpipe trim, including the sound flap, for an even more distinctive sound.
A new manual six-speed transmission is responsible for transferring the power in the Audi TT RS. Its shafts and gears can easily accommodate the high forces. A constant-velocity joint able to withstand high temperatures replaces the usual Hardy disk between the bevel box and the cardan shaft. Gear changes are performed swiftly, with precision and ease – just as you would expect on an Audi. The gear throws were shortened, and the shift lever and knob have been matched to the interior design of the TT RS.
The version of the quattro permanent all-wheel drive for transverse engines is standard in the TT RS. The central component of this system is an electronically controlled, hydraulically actuated multi-plate clutch. To further improve the already good axle load distribution, the clutch is mounted on the end of the cardan shaft upstream of the rear axle differential, another newly developed, particularly compact component designed for high loads.
A package of plates running in an oil bath within the center clutch housing can be steplessly pressed together by controlled hydraulic power. The controller constantly analyzes the driving conditions. If the front wheels begin to slip, an electric-powered rotary piston pump instantly builds up oil pressure, which the clutch uses to divert a large portion of the torque to the rear wheels. Thanks to a high-performance pressure accumulator, this process takes just a few milliseconds.
In the TT RS, quattro permanent all-wheel drive offers all of the superior capabilities that have long come to characterize Audi – added grip, slip-free acceleration, driving dynamics, safety and straight-line stability. The TT RS driving machine is dynamic and confidently stable no matter what the driving style or weather conditions.
When it comes to the suspension, the TT RS takes advantage of all of the excellent qualities the basic design of the TT has to offer. The front wheel suspension, with a track of 1,555 millimeters (5.10 ft), is a McPherson structure with triangular lower wishbones. The pivot bearing, the subframe and the control arms are made of aluminum; the subframe is bolted to the body at six points for greater rigidity.
The modified characteristic of the variable-assist rack-and-pinion-steering matches the dynamic character of the TT RS. Because the electromechanical system does not require any energy when traveling straight, it is extremely efficient and saves approximately 0.2 liters of fuel per 100 km. The 16.9:1 ratio is sporty and direct.
Thanks to its sophisticated design, the four-link rear axle (track: 1,546 millimeters (5.07 ft) can provide longitudinal and lateral support separately. The longitudinal links absorb the driveline and braking forces, and their relatively soft mounts provides good ride comfort. On the other hand, the three wishbones per wheel – the spring link, the upper wishbone and the tie rod – are attached very rigidly to the subframe, for optimum handling characteristics.
The elastokinematics of the rear links – all made of high-strength steels – are slightly modified from the technical foundation. Separate coil springs and newly developed dampers provide vertical support. The TT RS is 10 mm (0.4 in) lower than the high-volume TT. The developers perfected the setup in exhaustive testing, including many fast laps around the North Loop course at the Nürburgring.
The top-of-the-line TT is available with an optional electronic controller for the shock absorbers – the high-tech Audi magnetic ride system. Circulating within the damper pistons is a synthetic hydrocarbon containing tiny magnetic particles between three and ten micrometers in size. When a current is applied to a coil, a field is generated in which the alignment of the particles changes. They align perpendicular to the flow of the oil and thus prevent it from flowing through the piston channels. The characteristic of the damping thus changes within just a few milliseconds.
The system’s controller analyzes the driver’s style and the condition of the road constantly and adapts the function of the system accordingly. The driver can use the Sport button to switch between the normal characteristic and Sport mode. In standard mode, when oil viscosity is high, the TTS offers a well-balanced, comfortable ride. In Sport mode – with restricted flow – the ride is uncompromisingly stiff with practically no lateral roll. The targeted support of the wheels provides for more neutral self-steering behavior and more precise steering response.
A solid basis: 18-inch to 20-inch wheels
TT RS comes standard from Audi with large, 5-twin-spoke cast aluminum wheels in the size 9J x 18 shod with 245/40 tires. A number of wheels in various designs and sizes up to 20 inches are optionally available. The 19-inch wheels with 255/35 tires are optionally available in high-gloss silver or titanium look.
The large wheels have room for powerful brakes. All four disks are internally ventilated and measure 310 millimeters in diameter at the back and 370 millimeters up front. The front friction rings are perforated for maximum heat dissipation and connected by hollow pins to the aluminum brake disks. Four- piston calipers, painted black and decorated up front with RS logos, firmly grip the disks. These are also manufactured of aluminum to reduce the unsprung masses.
The ESP electronic stabilization program is designed for dynamic driving and can be deactivated in two stages. In Sport mode, the engine does not intervene to control traction, and the brakes engage later than otherwise. In the second mode, the ESP is fully deactivated.
From a purely visual standpoint, the TT RS Coupé and Roadster are both charismatic athletes. When standing still, they both appear to be pushing forward. The strong sheet-metal body and the tautly curved surfaces, delimited by sharp lines, give the impression of a sculpture in motion. A series of design highlights impart the TT RS with that air of concentrated power that characterizes a top-ofthe- line model.
As always with Audi, the front end is characterized by the single-frame grille, which is encircled by a matt aluminum-look frame. The grille insert, which bears a TT RS badge, features a shiny black rhombus design – a design mirrored by the large side air intakes. Their widely extended edges draw air into the engine compartment – the left intake routes the air across the gearbox; the right intake routes air to an additional water cooler. The turbocharger draws its intake air through the upper section of the single-frame grille, while the intercoolers sit behind the lower segment of the grille.
The front skirt has been redesigned. Its splitter and the rear spoiler work together to provide perfect aerodynamic balance. Audi offers the splitter, the lip of the diffuser insert and the mounting for the rear spoiler in aluminum look as an option.
The headlamp design is an identifying feature of all current Audi models. Xenon plus lamps are standard on the TT RS. They are accentuated by daytime running lights, whose 12 light-emitting diodes form a straight line. Together with the “wings” (dual plastic wings), the LEDs make the headlamps seem like little technical works of art.
The most striking aspects of the Audi TT RS when viewed from the side are the 18-inch wheels with the large brakes and the flared side sills. The outside mirror housings come standard in matt aluminum look, and optionally in the body color or carbon. Those looking for something special can choose the black styling package, in which the frame of the single-frame grille is also black.
The rear bumper includes an integrated diffuser insert that surrounds the two large, oval tailpipes. A TT RS logo also adorns the rear of the car. The TT RS comes standard with a wide, stationary spoiler that increases the downforce on the rear axle and thus improves stability at high speeds. The spoiler of the high- volume model, which automatically extends at 120 km/h (75 mph) and retracts again at 80 km/h (50 mph).
Regardless of which rear spoiler is chosen, the TT RS has a drag coefficient of approx. 0.32 (Roadster: 0.34). The front face measures 2.09 square meters (22.5 sq ft) in all versions – a low value that contributes to the high dynamism in the upper speed range. The Coupé and Roadster are 4,198 millimeters (13.77 ft) long and 1,842 millimeters (6.04 ft) wide. The closed TT RS is 1,342 millimeters (4.4 ft) high; the open version 1,348 millimeters (4.42 ft).
A classic lightweight: The Roadster’s cloth top
An open-topped Audi always has a classic cloth top. Why? Because it is lighter than a folding steel roof, lowers the center of gravity, takes up less room in the trunk and flows harmoniously into the design line. The cloth top of the performance driving machine TT RS Roadster is powered as standard by an electrohydraulic drive.
The top, which includes a large glass rear window, opens and closes in twelve seconds, even while driving at speeds up to 50 km/h (31 mph). When opened, it folds into a Z-shape with its frontmost element forming a fixed cover, eliminating the need for a cover flap or tonneau cover. A mat between the headlining and the outer skin provides good acoustic and thermal insulation. The wind deflector is also very convenient – it opens and closes automatically at the push of a button.
The cloth top is available in two sporty colors – dark grey or black. There are eight paint colors available for the body. Four of them are familiar from the TT family – Ibis White; Misano Red, pearl effect; Monza Silver, metallic; and Phantom Black, pearl effect. The following colors are offered exclusively for the TT RS: Daytona Gray, pearl effect; Mugello Blue, pearl effect; Sepang Blue, pearl effect; and Suzuka Gray, metallic.
A true sports car is always a light car, and the TT RS shines in this discipline as well. The Coupé weighs only 1,450 kilograms (3,197 lb); the Roadster 1,510 kilograms (3,329 lb). The power-to-weight ratio of 4.3 and 4.4 kilograms (9.5 and 9.7 lb) per hp speaks volumes about the dynamic potential.
The decisive factor is the construction of the two bodies. Up front they are made of lightweight aluminum components assembled using Audi Space Frame ASF technology. Extruded sections, die-castings and aluminum sheets form an impact- resistant structure of exceptional strength. The joint between the roof and the sidewalls of the Coupé are laser-welded as an invisible joint – a visual expression of the precision demanded by Audi. Steel is used at the rear of the floor pan, the doors and the trunk lid. This hybrid construction results in excellently balanced weight distribution.
The body-in-white of the Coupé weighs only 206 kilograms (454 lb), comprising 140 kilograms (309 lb) of aluminum (68 percent) and 66 kilograms (146 lb) of steel (32 percent); an all-steel structure would have weighed almost half as much again. The superstructure of the TT RS Roadster adds only 45 kilograms (99 lb). Components such as the steel bulkhead partition between the passenger cell and severely ribbed side sills provide added rigidity. The windshield frame and the two rollover bars protect the passengers if the car should roll over.
The Roadster and the Coupé are equipped with front airbags that discharge in two stages depending on the severity of the accident. Belt tensioners and force limiters protect the driver and passenger. In the event of a rear-end collision, headrests support the back of the head; head-thorax side airbags stand at the ready in case of a side-impact collision.
The neatly sporty interior design, the perfect ergonomics and the unique selection and build quality of the materials are hallmarks of an Audi. In the TT model series, special features provide that extra emotional touch – the curved cupola above the instruments, the instrument faces recessed into tubes, the large control knobs of the automatic air conditioning system and the round air vents.
The TT RS includes additional, lovingly arranged details. A special menu including digital displays for boost pressure and oil temperature as well as a lap time for recording lap times on the racetrack is integrated into the standard driver information system. The display of the optional navigation system plus greets the driver with a special TT RS screen when the ignition is turned on. The leather multifunction sports steering wheel has three spokes and an extra thick ring. It is flattened at the bottom like in a racing car and is wrapped with perforated leather with silver seams.
The sport seats are mounted low. Their large side cushions provide perfect support, and the seats are infinitely adjustable and heated. They come standard in a combination of leather and Alcantara, accented with contrasting silver seams and embossed TT RS logos in the front backrests.
The entire interior is dressed in dynamic black. Matt brushed aluminum inlays are standard; the footrest and pedals are in aluminum look. TT RS logos adorn the door sill trims, the tachometer and the steering wheel, silver welts frame the floor mats, and the door openers – typical for an Audi RS model – comprise two narrow bars.
The TT RS is a sports car with good everyday usability – a major strength of the entire model series. The backs of both rear seats fold down in the Coupé, increasing trunk space from 290 to 700 liters (from 10.24 to 24.72 cu ft). The Roadster, which offers 250 liters (8.83 cu ft) of storage space, can be optionally equipped with a load-through hatch with a removable ski sack.
The TT RS is sportily and generously equipped by Audi. Among the highlights of the standard equipment are quattro permanent all-wheel drive, the large 18-inch alloy wheels, the xenon plus headlamps with LED daytime running lights and, in the Roadster, the electrohydraulic top with power wind deflector. The interior is dominated by the leather multifunction sports steering wheel and the sport seats with their leather/Alcantara surfaces. An automatic air conditioning system and concert audio system with CD player are also standard equipment in the German market.
Audi also offers a broad range of convenient optional extras. These include two navigation systems with refined software, a Bose sound system, a parking assistant, a hill-start assistant, cruise control, an interior lighting package with LED lamps and the adaptive light dynamic cornering light system.
Additional features are exclusive to the TT RS, such as the bucket seats with fold- down backrest. They are covered in black Fine Nappa leather with contrasting silver seams. The inserts of the seat side sections and the top center strip of the backrest are perforated in the shape of the letters TT. Audi offers the standard sport seats in Silk Nappa leather with perforated embossing – in either black or silver with contrasting seams and perforated inserts in the center strips and on the seat side sections.
Floor mats with TT RS logos, control elements covered in suede and painted inlays in phantom black or ibis white impart the interior with an even more individual note. The Audi exclusive program from quattro GmbH accommodates the wishes of those who are after that extra-special touch.
Audi is scheduled to begin delivering the TT RS this summer. The Coupé is Priced at €55,800 and the Roadster at €58,650.
The five-cylinder model from Audi
The 2.5-liter engine in the Audi TT RS follows a long tradition: Audi was the brand most noted for its five-cylinder engines in the 1980s. The powerful engines sharpened the new, sporty profile and made a decisive contribution to Vorsprung durch Technik.
The five-cylinder unit was a stroke of engineering genius, unifying the efficiency of a four-cylinder with the cultivation of a six-cylinder at a lower weight and compact dimensions that permitted transverse mounting in front of the front axle. It debuted in spring 1977 in the Audi 100 5 E and was a hit from the very beginning. Fed by a hypermodern fuel injection system, the 2.1-liter engine produced 100 kW (136 hp) to offer strong performance with good fuel economy.
The family grew quickly. A five-cylinder, normally aspirated diesel with a displacement of two liters and producing 51 kW (70 hp) was released in the fall of 1978. A year later saw the debut of the first turbocharged, five-cylinder gasoline engine – another pioneering feat from Audi. With an output of 125 kW (170 hp) and 265 Nm (195 lb-ft) of torque, the new top model, the Audi 200 5 T, was one of the fastest sedans of its day. The principle of downsizing – the use of turbocharging to replace displacement – already resulted in good power and high efficiency 30 years ago.
High-flying engine: The five-cylinder unit in the Audi quattro
A year later, the new engine had its biggest impact yet – in the 1980 Audi quattro. The two technologies, turbo and all-wheel drive, quickly formed a dynamic duo of success on the road and on the racetrack. The turbocharged five-cylinder produced 147 kW (200 hp) when it first went on sale. In the 1984 Sport quattro, a direct motorsports derivative, it produced 225 kW (306 hp) – and was thus the high-flying engine of the 1980s.
The strength and ruggedness of the Audi design was proved in the World Rally Championship competition cars, where the highly-boosted five-cylinder churned out a good 350 kW (476 hp). The high point in the motorsports career was marked by two extreme racing cars. The Audi Sport quattro S1, with which Walter Röhrl won the Pikes Peak (USA) mountain race in 1987, produced roughly 440 kW (approx. 600 hp). And the IMSA-GTO, a touring car based on the Audi 90, dominated the US racing scene with 530 kW (approx. 720 hp) from only 2.2 liters of displacement.
In series production, Audi continuously refined its range of five-cylinder gasoline engines, which had displacements ranging from 1.9 to 2.3 liters. The engine concept also enjoyed great success in the diesel sector. The 1989 Audi 100 TDI, a 2.5-liter model putting out 88 kW (120 hp) and 261 Nm (193 lb-ft), is a milestone of automotive history.
In the mid-1990s, the five-cylinder engines were gradually replaced by the new V6 units, but not without one last hurrah: The 1994 RS 2 produced 232 kW (315 hp). As a sophisticated Avant with the power of a sports car, it established an entirely new class of automobile.