First introduced as a concept at the 1995 Frankfurt Auto Show, Audi’s mighty, yet compact TT sport-coupe has changed little since its inception. But with its war-on-weight campaign, Audi decided the already lightweight TT could use a trim. So off to the fat farm went the Ultra Quattro Concept, and when all was said and done, a 300 kg (661 lb) lighter vehicle remained.

The diminutive TT, which stands for “Tourist Trophy” from the Isle of Mann race series, may be highly impractical as a family vehicle but has received kudos over the years for its contemporary, iconic styling and high fun-to-drive factor. With little to improve on from a mechanical or engineering perspective Audi set out to lighten the load.

Significant structural and material revisions are to thank for much of the pound shedding. The Ultra Quattro Concept tips the scales at a seriously svelte 1,111 kg (2,450 lb), which makes for an impressive power-to-weight ratio of around 275 hp per ton through a 2.0-liter TFSI engine.

Naturally, the TT’s body and chassis were the first places Audi’s fitness gurus went to work. A production TT, with a low body weigh-in of 206 kg (454 lb), is already a fit street fighter, but thanks to the concept’s new body revisions and materials, another 43 kg (94.8 lb) was shed from the package. When figuring detachable body parts into the equation, a total of 100 kg (220 lb) was shed from the body alone. Carbon fiber-reinforced polymer (CFRP) in the rear end, center tunnel, B-pillars and in the roof also contributed to the weight-loss program.

Weight reduction measures to the four-cylinder powerplant come in the form of modifications to the crankcase, crankshaft, balancer shafts, flywheel, sump, bolts and select ancillary units. All these tweaks helped reduce engine weight by 25 kg (55 lb). Chopping this type of weight from an engine is an impressive engineering feat in itself. Again, lower engine weight means less to manage under extreme driving situations thanks to quicker transitional abilities and better handling characteristics.

Unsprung weight, anything not supported by the vehicle’s suspension, is an important weight detail often overlooked during performance upgrades. In the case of the TT Ultra, suspension weight-loss came in the form of fiberglass-reinforced polymer (FRP) coil springs, which replace conventional steel coil springs.

The core of these new hi-tech, lightweight springs is made up of long glass fibers, twisted together, then impregnated with epoxy resin. A machine then wraps additional micro-fibers around the core at alternating angles of plus/minus 45 degrees to the longitudinal axis. These layers in turn support each other and provide the necessary compression/ decompression functionality. According to Audi, this FRP suspension modification reduces unsprung weight on the TT by 40 percent.

Revised front brakes with ceramic discs, aluminum fixed calipers, a titanium exhaust system and CFRP wheels with high-strength aluminum spokes, all played a part in shaving another 20 kg (44 lb) from the TT.

Not only will the TT Ultra Quattro Concept see handling and braking improvements from the strict diet, but performance will also benfit. With a power upgrade to roughly 305 hp and 400 Nm (295 lb.ft) of torque, the TT can now do the 0 – 100 km/h (62 mph) sprint in 4.2-seconds. A significant jump from its heftier brethren. Top speed for the TT Concept is rated at 273 km/h (170 mph).

The Audi Ultra Quattro Concept will be on show at next month’s Wörthersee festival in Germany.

Source: Audi

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