http://www.autocar.co.uk/CarReviews/...totype/242969/
Audi A5 lightweight prototype
Test date Monday, September 07, 2009 Price as tested TBA
What is it?
Audi’s experimental lightweight version of the A5 coupe. The standard A5 is built around a conventional steel monocoque chassis, but this car is built around an aluminium spaceframe chassis, clad in aluminium panels. The boot and bonnet are made from carbonfibre-reinforced plastics.

Under the skin of the prototype is Audi’s familiar 2.0 TSI turbocharged engine, wound up to 208bhp and driving all four wheels.

Audi says this car points the way forward for the company. Aluminium construction will become more common, allowing future cars to benefit from all-round ‘downsizing’.

This means four-cylinder engines instead of sixes, smaller brakes, wheels and tyres, smaller fuel tanks, better economy and – most important – much-improved ride and handling.

This latter claim is said be a consequence of reducing unsprung weight and, for high-performance models, using lighter, shorter engines that sit further back in the engine bay.

Overall this car is 230kg lighter than a standard-issue A5 3.2 V6 quattro, the performance of which Audi says the lightweight coupe can match despite its power shortfall.

Company engineers say the A5’s aluminium spaceframe construction saves around 110kg over the standard car and the carbonfibre lids save around 50kg. Another 25kg is shaved off by using a four-cylinder engine. The final 45kg comes with ‘hybrid’ brake discs (which are made from gray cast iron, bolted to aluminium centres) and new lightweight wheels.

Audi has also embarked on a general programme of shaving back the weight of all under-skin components, introducing plastic clutch pedals and seats backs as well as detail refinements such as superlight exhausts and even aluminium bolts and screws.

What’s it like?
Autocar had a chance to try the two A5s back to back on a few quick laps of the Bosch test track at Boxberg.

The 3.2-litre A5 (thankfully without S-line suspension) was smooth, torquey, brisk and surprisingly agile on switchbacks, though that was partly thanks to the quattro drivetrain and its positive effect on the A5’s weight distribution.

The lightweight A5 was markedly different. Its weight advantage was starkly obvious, resulting in rather less of a GT feel and more that of a nippy hot hatch. And it did change direction more quickly, losing much of the slight ponderousness that remains in even the new-generation, longitudinally engined Audis.

However, the rougher four-cylinder engine and its gruffer soundtrack were at a marked disadvantage to the sweet V6 unit. Although future A5 buyers will appreciate the car’s newfound fleetness, they could miss the cultured response of a big engine and the luxury overtones that are a consequence of weighty chassis responses.

Audi engineers say they are well aware of this problem and promise the next generation of four-cylinder engines will have to be both much smoother and more aurally upmarket.

Sadly, the smooth Bosch track prevent us from making any definitive statement on the claimed improvement in ride quality, but the dramatic lighter brake discs and wheels will be a huge help on broken UK roads.

Should I buy one?
You can’t. At least not for another few years, until the A5 is replaced as part of Audi’s new aluminium platform strategy.

The big issue for the next A5 will be cost, because aluminium is a more costly material than even the most sophisticated steels, a hurdle that will only partly be offset by mass-manufacturing aluminium platforms.

The company could, though, further offset the extra cost of an aluminium body by dropping V8 engines and most of its V6 units, and fitting cheaper downsized motors.

However, the next-generation four-pot engines will have to be sufficiently smooth and burbling to deliver a premium feel. If Audi’s engineers manage that, the gains in agility, performance and fuel economy delivered by the switch to aluminium could become class leading.

Mysterious Audi Interior
Here are a few photographs of an intriguing new Audi interior. First thought to be the interior of the forthcoming A8, it is now believed to be a new version of the A4 interior. The most noticeable change to the standard A4 interior is the revised instrument panel featuring a large display between the tachometer and speedometer. While the Audi that the interior belongs to will remain a mystery for now, expect to see the new display and gauges coming to an Audi in the future.

Who says that wagons are uncool and slow?
BY MIKE SUTTON, PHOTOGRAPHY BY JORDAN BROWN
January 2010

Despite the popularity of station wagons in Europe, as well as their greater versatility compared with that of conventional four-door sedans, two-box cars like this Audi A4 2.0T Avant still don’t resonate with most U.S. consumers. Americans for the most part remain tied to visions of Clark Griswold trundling across the country in a puke-green, wood-paneled Ford LTD Country Squire and would rather drive something else. But this country has in fact been in love for the past 20 years with what are essentially wagons. Witness the rise of the SUV and the recent explosion of crossovers—all of which are basically five-door wagons with higher seating positions, greater (but often unused) towing and payload capacities, and cruddier fuel economy.

Move ’Em Out

This Audi, however, makes a great case for the traditional wagon. Although it’s no fire-breathing RS 6 Avant, our A4 Avant was far more maneuverable and exciting to pilot than those SUV and crossover mall cruisers. Based on the A4 sedan, our Avant was fitted with Audi’s excellent 211-hp, 2.0-liter turbocharged four-cylinder—the only engine in the A4 lineup for 2010—plus a six-speed automatic and Quattro all-wheel drive. It also had the optional S-line package, which includes a sport suspension, 19-inch wheels with summer rubber, front sport seats, various interior trim upgrades, and S-line bumpers and rocker panels. Thus equipped, the A4 Avant recorded a 6.3-second run to 60 mph and a quarter-mile time of 14.8 at 91 mph, times that beat all the players in our last comparison test of six-cylinder luxury crossovers. Perhaps more important, the Audi’s 0.92 g of skidpad grip blows away that group’s average of 0.80 g, as does its fun-to-drive quotient on back roads. And it’s the same with 70-to-0 braking ability: 159 feet for the A4 wagon versus an average of 174 for the crossovers.

Credit the A4’s lower center of gravity and lighter weight for much of its dynamic ability. At 3840 pounds, it’s less bulky than most luxury all-wheel-drive crossovers with similar interior volumes, a characteristic that also lends the A4 Avant respectable fuel-economy ratings of 21 mpg in the city and 27 on the highway. Although our 18-mpg average is closer to an SUV’s, that was the result of extended bouts of spirited, high-speed driving; we’re averaging a more representative 26 mpg with our long-term A4 2.0T sedan, which is only 177 pounds lighter.

Load ’Em Up

Aside from its reduced heavy-hauling ability, the A4 Avant scores high against SUVs and crossovers in practicality, too. Although it probably will never tackle anything more than a dirt road—it’s not as if most crossovers were any different—the five-door A4 is all-season capable and rather spacious. The Audi’s lower ride height makes loading and unloading cargo a snap, and there’s a generous 28 cubic feet of space behind the back seat and 51 cubes with it folded flat. That capaciousness puts it about on par with an Audi Q5 or Mercedes-Benz GLK-class, but it’s slightly less than that of, say, a Lexus RX. Other, larger crossovers can sport a third row of somewhat inhabitable seats, but the A4 Avant’s two rows should suffice unless what you really need is a minivan or a Chevy Suburban.

Break the Bank

In terms of pricing, the A4 Avant is about $3000 more than a comparable A4 sedan. Well equipped to start at $36,175, our example had that S-line package ($2450) and the $9200 Prestige package—navigation, a Bang & Olufsen sound system, a power liftgate, xenon headlights, LED running lights, heated front seats, Bluetooth, iPod connectivity, and keyless access and ignition, among other bits—bringing the as-tested total to $48,300. That’s not cheap, but the content and the dollars are comparable with those of premium crossovers of similar size. And there’s that whole driving enjoyment thing, which we can’t really put a price on.

For an apples-to-apples comparison, the similarly sized Cadillac CTS sport wagon with all-wheel drive and the 3.0-liter V-6 starts at $40,990. However, the rear-wheel-drive model we previously tested with the 304-hp, 3.6-liter V-6 started at $44,055, was optioned to nearly $55,000, and significantly trailed the Audi in every performance category except 70-to-0 braking, in which it tied the A4’s figure at 159 feet. BMW’s fine 328i sport wagon is comparably priced and the Volvo V70 with a 3.2-liter inline-six starts at $34,400, but the latter is front-drive only and is about as exciting as potting soil.

Win-Win

Unfortunately, premium wagons’ relatively high sticker prices and resulting low volumes aren’t much help in convincing Americans of the body style’s inherent goodness. (Affordable mainstream models would help, but the Toyotas and Fords of the world stopped building them some time ago.) That’s too bad, because this Audi certainly does present a compelling argument in the form of its attractive five-door package—especially with the 19-inch S-line wheels—and great usability and refinement. Tack on the greater efficiency, performance, maneuverability, and driving fun against most traditional crossovers or SUVs, and we’re surprised more people aren’t swayed. Besides, unlike Clark’s old Country Squire, the A4 Avant actually could keep up with a hot blonde in an old Ferrari.



Highs: Sharp looks with S-line package, wonderful interior, five-door versatility with sport-sedan performance.

Lows: Pricey with options, heavy feet make for poor fuel economy, station-wagon stigma.

Top Competitors

BMW 3-series sports wagon
Infiniti EX35
Saab 9-3 SportCombi
Volkswagen Passat wagon
Volvo V50

Specifications

VEHICLE TYPE: front-engine, 4-wheel-drive, 5-passenger, 5-door wagon
PRICE AS TESTED: $48,300 (base price: $36,175)
ENGINE TYPE: turbocharged and intercooled DOHC 16-valve inline-4, iron block and aluminum head, direct fuel injection
Displacement: 121 cu in, 1984cc
Power (SAE net): 211 bhp @ 4300 rpm
Torque (SAE net): 258 lb-ft @ 1500 rpm
TRANSMISSION: 6-speed automatic with manumatic shifting
DIMENSIONS:
Wheelbase: 110.6 in Length: 185.2 in
Width: 71.9 in Height: 56.5 in
Curb weight: 3840 lb
C/D TEST RESULTS:
Zero to 60 mph: 6.3 sec
Zero to 100 mph: 18.6 sec
Zero to 120 mph: 33.8 sec
Street start, 5–60 mph: 7.8 sec
Standing ¼-mile: 14.8 sec @ 91 mph
Top speed (governor limited): 130 mph
Braking, 70–0 mph: 159 ft
Roadholding, 300-ft-dia skidpad: 0.92 g
FUEL ECONOMY:
EPA city/highway driving: 21/27 mpg
C/D observed: 18 mpg