By: Dave Abrahams
Ingolstadt, Germany - Each year the Volkswagen group builds some rather special machinery for the annual Wörthersee Tour enthusiasts' gathering on the second weekend in May and, because this is a party for performance junkies it's always a runner, not a static design study.
This year it's Audi's turn, and the Fellowship of the Four Rings have outdone themselves - not only is their Clubsport Turbo TT concept a serious performance car, it combines some genuinely new technology with iconic design cues (and sounds!) from the '80s.
This, according to Audi board member for technical development Ulrich Hackenberg, is the hottest TT coupé ever to turn a wheel, delivering 442kW and 650Nm from its 2480cc five-cylinder engine - that's 177kW per litre! - thanks to a biturbo combination using a conventional exhaust-driven compressor in tandem with a 'blower' driven, not by a power-sapping belt from the crankshaft, but by a 48-volt electric motor.
Hackenburg says the technology is close to production-ready for the group's TDI oil-burners, but the TT Clubsport is the first time it's been applied to a petrol engine.
THIS IS HOW IT WORKS
The electric compressor spins up to maximum revs almost instantly, completely negating turbo lag, and continues pushing charge pressure when there's too little energy left in the exhaust gases to drive the conventional turbo.
That provides instant charge pressure, right from idle - something not even the gynormous belt-driven superchargers on American drag-racing cars can do - and boosts torque output by up to 200Nm right at the bottom of the rev range, making it possible to use a full-tilt-boogie racing turbo set up specifically for top-end power.
Finally, a shorty racing muffler, designed for minimum back-pressure, leads to a big-bore side pipe that howls and crackles and spits purple flames on the overrun like the iconic Quattro rally cars of the 1980s.
The compressor motor gets its amps from a dedicated 48-volt electrical sub-system, with a compact lithium-ion battery in the boot that stores energy generated by recuperation when coasting; a DC/DC converter allows it to charge the car's conventional 12-volt electrical system as well.
The power is laid down through a six-speed manual gearbox and quattro permanent all-wheel drive, with its multi-plate centre clutch mounted on the rear axle for more even weight distribution.
AND THIS IS HOW IT GOES
The show car runs on 20-inch rims shod with 275/30 gumballs, over 370mm carbon-ceramic brake discs, and weighs only 1396kg ready for the strip, where it'll launch from 1-100km/h in 3.6 seconds and top out at 307km/h.
But its big advantage is in the first few metres. Instant boost gets it 16 metres off the line in the first 2.5 seconds - six metres (one and half car lengths) further than a comparable car with conventional turbo induction.
Coilover suspension all round enables precise adjustment of compression and rebound damping, as well as ride height (there's also an electric lifting function to guard against damage from kerbs and speed bumps) while electronic stabilisation control and torque vectoring take care of the understeer inherent in all-wheel drive performance cars.
The Clubsport Turbo TT is 4330mm long and runs 1736mm front and 1729mm rear track widths; at 1970mm overall it's 140mm wider than a standard TT. Its angular wings add a whole new dimension to the body shape, intentionally reminiscent of the Audi 90 IMSA GTO race car of the late 1980s, and they're open front and rear to channel cooling air over the brakes.
The manually adjustable rear wing has been developed from the standardised wing on the Audi Sport TT Cup series racers. It's 200mm wider, with revised side flaps featuring a four-ring motif, and it's made of carbon fibre, as are all the add-on bits: the air inlets and the large splitter at the front, the side panels and side sill trims as well as the large rear diffuser.
DRIVER-FOCUSED
The stripped out 'race car' cockpit has a rear suspension brace/roll-cage made of ultra-high-strength, super-lightweight titanium tubing, and it's trimmed in carbon fibre and black alcantara synthetic suede throughout, other than the lightweight race-spec bucket seats with four-point harnesses in coral orange.
The air vents and gear shifter have coral orange accents, and the aluminium gear shift lever travels in a Ferrari-style open shift gate.
The digital virtual instrument display is focused on the driver, who can control all key driving parameters from just four satellite buttons on the multifunction steering wheel.
And the best part? Other than that seriously authoritative exhaust note (and that could easily be sorted by extending the tailpipe to the rear) the Clubsport Turbo concept is street legal. Chew on that, Porsche GT3 RS fans.