Audi is turning the Wörthersee 2013 into the “Home of quattro”. At the large gathering from May 8 to 11 in Reifnitz (Kärnten), the premium brand will unveil the Audi TT ultra quattro concept – which combines minimal weight and maximum sportiness. A wide range of high-performance cars will also give fans another taste of sportiness. In addition to the legendary Sport quattro S1, the very latest RS models and thoroughbred race cars are also on show. The Audi R18 e-tron quattro, which was the first hybrid car to win the 24 Hours of Le Mans last year, will also be part of the action at the lakeside.
At the start of May every year, the Wörthersee is the place to be for every car and Audi aficionado. Audi will therefore be showcasing a special highlight in 2013: the Audi TT ultra quattro concept. The showcar combines a lean 1,111 kilograms (2,449.34 lb) total weight with a 2.0 TFSI engine, whose 228 kW (310 hp) and 400 Nm effortlessly propel the coupé. From a standstill the TT ultra quattro concept is catapulted in 4.2 seconds to 100 km/h (62.14 mph). Its power-to-weight ratio of 3.6 kg/hp is on a par with thoroughbred super sports cars. And it is also worthwhile looking at the detail, not least because the concept car pays homage to automotive lightweight construction.
Even the current series-production car with a body weight of just 206 kilograms (454.15 lb) plus 98 kilograms (216.05 lb) for the detachable body parts is testimony to the outstanding lightweight construction expertise of Audi. The engineers from Ingolstadt and Neckarsulm concertedly fine-tuned the Audi Space Frame (ASF) in the current TT generation to come up with the body for the Wörthersee showcar, shedding another 43 kilograms (94.80 lb) from the body structure. Together with the optimized detachable body parts, the result is a weight saving of 100 kilograms (220.46 lb).
Audi has adopted an intelligent mix of materials according to the motto: the right amount of the right material in the right place. The Audi TT ultra quattro concept uses carbon-fiber reinforced polymer (CFRP) in the rear end, the center tunnel, in the B-pillars and in the roof. Magnesium components in the floor and as hinge reinforcement reduce weight even further.
The combination of lightness and sportiness is also reflected in the looks. Compared with the series-production model, the Audi designers have substantially honed the showcar’s contours even further. With its large spoilers, the TT ultra quattro concept proudly displays its motorsport genes. The base of the rear wing is manufactured as a supporting component from milled aluminum, while the wing, as a functional element, is made of visible carbon.
The concept car is painted in the special color crystal white. The CFRP used on the exterior adds a striking touch on the hood, the roof, the sides and the trunk. In the interior the same material also adorns the door trim, the center console and the cross-bracing that replaces the rear seat bench. The developers have also fitted the bucket seats from the R8 GT to the concept study; their chassis alone, made out of fiberglass-reinforced plastic (FRP), reduce weight by 22 kilograms (48.50 lb). The driver does not have to make any compromises when it comes to equipment and appointments: air conditioning, electric window controls and an electromechanical parking brake come as standard on the TT ultra quattro concept. A veritable highlight: the exterior mirrors are replaced by compact cameras which transfer the images directly into the digital cockpit.
To reverse the weight spiral, the Audi ultra lightweight construction concept is applied to all elements in the automobile. The developers have further optimized each component. The front brakes feature ceramic discs with an aluminum fixed caliper, the exhaust system made out of titanium ends in a single central tailpipe. The wheels also reduce weight by 20 kilograms (44.09 lb). Spokes made out of high-strength aluminum are bolted directly to the CFRP wheel.
Every gram counts, particularly on the suspension. Here the unsprung masses have been reduced, thus improving comfort and handling. On the TT ultra quattro concept the coil springs are not made out of steel but from fiberglass-reinforced plastic (FRP). The core of the all-new springs consists of long glass fibers twisted together and impregnated with epoxy resin. A machine wraps additional fibers around this core, which is only a few millimeters in diameter, at alternating angles of plus and minus 45 degrees to the longitudinal axis. These layers support each other and act in either compression or tension. The use of FRP at this point cuts weight by 40 percent while maintaining good characteristics – 6 kilograms (13.23 lb) in relation to the car as a whole.
To further hone the handling of the TT, the developers have taken away weight from the ends of the car and moved it into the middle. The lithium-ion starter battery, for instance, is located in the interior under the driver’s seat. It is much smaller than a lead battery and weighs as little as just under four kilograms (8.82 lb).
Overall, all these lightweight construction measures make the concept car about 300 kilograms (661.39 lb) lighter than the comparable sporty series-production model. All of which helps minimize the inertial mass that the 228 kW (310 hp) 2.0-liter TFSI engine contends with during acceleration. The modified high-end four-cylinder unit develops its maximum torque of 400 Nm between 1,900 and 5,000 rpm, putting it on a par with the power of the V8. Modifications to the crankcase, the crankshaft, the balancer shafts, the flywheel, the oil sump, the bolts and certain ancillary units that make the engine 25 kilograms (55.12 lb) lighter have all helped get the engine into tip-top shape.
Thus the Audi TT ultra quattro concept offers the kind of driving experience that automotive fans on the Wörthersee expect from a genuine high-performance model. Like the “Ur-quattro” from 1980 and more than five million series-production vehicles since, this year’s showcar is also fitted with the quattro permanent all-wheel drive. Grip is therefore always ensured despite the impressive performance. With its six speed transmission, the TT ultra quattro concept is 1.3 seconds faster than the series-production model when accelerating from 0 to 100 km/h (62.14 mph). The top speed is 280 km/h (173.98 mph).
The Audi showcar demonstrates the technical possibilities of an intelligent mix of materials. In this way considerable weight savings can even be achieved on an existing series-production model. Usage of these technologies is conceivable for future small-batch series.