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Audi Aluminum A5 Coupe Prototype - Click above for a high-res image

Audi is continuing the aluminum architecture tradition employed on the A8, R8 and TT with a new prototype of the A5 that sheds 242 pounds from the standard 2.0-liter model.

The Aluminum A5 Prototype uses the steel-bodied production vehicle as its base, then incorporates the Audi Space Frame (ASF) technology and a carbon fiber hood and trunk to bring the curb weight down from 3,130 pounds to 2,888 pounds. Compared to the V6 model, the 208 hp turbocharged 2.0-liter model has a power-to-weight ratio of 159-hp per ton, while the V6 variant trumps it by only 11 hp per ton.

While Audi's aluminum technology is sure to find its way into future models, including the A5, Audi doesn't plan to produce the current A5 using the ASF concept quite yet. That's likely to happen with the next generation model due out in a few years, but talk of an Ur-Quattro revival with the S5 (or RS5) could be the opening salvo with the coupe, and this is a good indication that work is well underway. Full details in the press release after the jump.



Lightweight construction pioneer highlights its technological lead

Dynamic and efficient: Audi – pioneer of lightweight design for enhanced performance and optimised efficiency
Aluminium-bodied A5 prototype aids development of the ASF concept
Over 550,000 Audi models with an aluminium body since 1994
New materials and technologies for the cars of tomorrow

A lightweight Audi A5 Coupe prototype has jettisoned over 100kg by swapping steel for advanced aluminium and carbon fibre construction in the interest of fuel economy, emissions reduction and handling agility. The A5 project is the latest example of the pioneering work undertaken by the Vorsprung durch Technik brand to extend efficiency optimisation measures well beyond the engine bay.

Taking an existing steel-bodied production car as its basis, the A5 project car clearly demonstrates the benefits of the aluminium Audi Space Frame (ASF) concept with which Audi broke new ground 15 years ago, and which test beds of this kind help to evolve and improve. Use of the ASF principle reduces the weight of a car body by at least 40 per cent compared with conventional steel construction, and this shows in a kerb weight of 1,310kg for the aluminium A5 prototype, versus a total of 1,420kg for the equivalent steel-bodied series production model.

Thanks to the significant weight loss, achieved by mounting aluminium and carbon fibre-reinforced plastics onto the aluminium Audi Space Frame (ASF), the A5 prototype is able to use a four-cylinder engine with its attendant economy and emissions advantages to deliver the performance of a higher output V6.

With the acclaimed 2.0-litre, 211PS Turbo FSI engine, the A5 achieves a power-to-weight ratio of 161PS per tonne. For comparison, the 'standard' A5 3.2 FSI V6 quattro with 265PS, which tips the scales at 1,540kg, shades it only by a fraction at 172PS per tonne.

The lightweight design of the test car not only enables a smaller engine to supplement a larger one with no impact on performance and gains in economy and emissions, but also has a knock-on effect on ancillaries such as the brakes and transmission, which can also be reduced in size and weight. It also enables the car to change direction noticeably more keenly and nimbly and, thanks to the reduction in unsprung weight, to ride with even more refinement.

15 years of lightweight construction experience
Over the past 15 years, Audi has employed the ASF principle in two generations of A8 luxury saloon, in the hyper-efficient, ahead-of-its-time A2 compact hatchback and in the celebrated R8 super car. ASF has also been re-interpreted in the creation of the latest TT Coupe and Roadster, which feature advanced steel and aluminium 'hybrid' construction that allows for outstanding weight distribution.

"One of our most enduring aims for the future is to reverse the weight spiral," says Michael Dick, Member of the Board of Management of AUDI AG responsible for Technical Development. "Lightweight design is the foundation of our entire approach to improving efficiency."

Lightweight design is a strategic responsibility at Audi. It makes a significant contribution to dynamic potential and efficiency, helping to conserve resources and reduce operating costs. The electric drives of the future will add additional weight to the car and will initially only offer a limited range, making systematic lightweight design all the more important.

ASF: the reversal of the weight spiral
The reversal of the weight spiral that Audi initiated with the ASF principle which began with the Audi A8 of 1993 has major efficiency advantages. Every 100kg saved reduces fuel consumption by 0.3 to 0.5 litres per 100 kilometres, corresponding to a reduction of 8 to 11 grams of CO2 per kilometre. A lighter body is also the starting point for weight reductions on other parts of the car, such as the chassis or the fuel tank.

Meanwhile lightweight bodies are an absolute prerequisite for the electric drive systems of the future with their heavy batteries. The performance and range expected by customers cannot be achieved without them.

Audi has already built more than 550,000 vehicles with an aluminium body. Added to this are roughly 9,000 Lamborghinis – no other manufacturer in the world can even come close in terms of the number of vehicles or their diversity.

The ASF technology is an unparalleled success story. Audi has increased its lead step by step: in alloys, in the reduction of the number of parts and in production efficiency. Numerous innovations in development and production have raised the level of automation from 25 to over 80 percent, which is nearly on par with steel body construction.

In fabrication, traditional spot welding is being replaced by joining methods developed by Audi, including punch riveting, bonding or laser-MIG hybrid welding. In the TT and the R8, self-tapping screws are used to join many of the components. Another innovation is the laser-welded invisible seam on the roof of the TT.

A8, R8, TT and TT Roadster: the state of the art
The second generation of the A8 and the R8, TT Coupé and TT Roadster sports cars document the current state of the ASF technology. The superstructure of the current A8 weighs 218kg while the aluminium body of the R8, whose co-supporting engine frame is made of ultra light magnesium, tips the scales at 210 kg.

The TT Coupé and Roadster bodies weigh 206 kg and 251 kg respectively while the TT "family" also features an additional innovation. To ideally balance the axle loads between the front and back, Audi developed an innovative hybrid construction for its compact sports cars: Most of the body is made of aluminium, but steel is used in the rear.

Depending on the model, the kerb weight of the TT has been reduced by between 20 and 90 kg compared to the previous model which had an all-steel body. At the same time, the static torsional rigidity of the Coupé increased by 50 percent and that of the Roadster by an even more impressive 100 per cent.

The ASF provides the foundation for precise handling and a high level of passive safety. A lighter car has to dissipate less kinetic energy and is also does less damage to others involved in an accident. The lightweight design combines chassis responsiveness and efficiency in typical Audi fashion.

Foundations were laid almost 100 years ago
NSU built the Type 8/24, featuring a body made entirely of aluminium, in 1913, and 10 years later, the Audi Type K wore an experimental streamlined skin of this same material. In the 1930s, specialists from the Racing department of Auto Union manufactured aluminium panels by hand and used them to build the bodies and streamlining panels for their spectacular racing cars and land speed record cars.

Lightweight design advanced to the level of a strategic project at Audi in 1982 to invent a self-supporting body with a material roughly two-thirds lighter than conventional steel and also with a new geometry tailored to this material – the Audi Space Frame.

In 1985, Audi presented the body of an Audi 100 made of aluminium but still using a conventional monocoque design. The legendary concept sports cars of 1991, the Audi Avus quattro and the Audi quattro Spyder, had skins of the light metal but underneath were still supporting frames.

The new technology was ready for series production in 1993. A shining silver showcar with an unpainted body of polished aluminium was on display at the Frankfurt Motor Show. The predecessor to the A8 bore the designation ASF, the abbreviation for Audi Space Frame. The production model that debuted the following year was a milestone – the first large-volume production car with a self-supporting aluminium body.

The A8 paved the way for Audi into the premium league and it also sparked new developments for the traditional material of steel. The principle embodied by the first A8 still applies today: Die castings and extruded sections form a framework-like skeleton that incorporates aluminium panels as co-supporting elements. The components with their various cross-sections and shapes combine optimal function with low weight.

The Aluminium and Lightweight Design Centre
Audi established a special Aluminium Centre in Neckarsulm for development, production planning and quality assurance in 1994. The Aluminium and Lightweight Design Centre experiments with high-strength steels, tailored blanks, fibre-reinforced plastics and magnesium.

Heinrich Timm, the Head of the Aluminium and Lightweight Design Centre, says: "Aluminium remains the primary material, but we are intensively investigating the other materials, with our primary focus on fibre-reinforced composites."

The lessons learned at the Aluminium and Lightweight Design Centre innovation foundry, which employs 150, have already served as the basis for a three-digit number of patents in development and production – a balance they can be proud of. The European Patent Office named Audi "European Inventor of the Year 2008" for its achievements with the ASF technology.

Lightweight design in the rest of the vehicle
Audi also makes systematic use of lightweight design in the drive chain and the chassis. Many engines uses aluminium and vermicular graphite cast iron, which is the result of a high-tech production process, to reduce the weight of the crankcase. Many models have chassis with predominately aluminium parts.

Carbon fibre-ceramic brake discs are available as an option in the high-performance models. Other highlights of lightweight design include brake callipers, bonnets and boot lids, side panels or cover components made of aluminium and steering wheel rims or instrument panel mounts made of magnesium.

Experience from the world of motor sports flows back into the development work – the reduction and distribution of weight are extremely important for Audi's pioneering diesel-engined Le Mans sports-prototypes and its DTM (touring) cars. The race cars provide the production development engineers with important information about carbon and its combination with metal.

Research continues into new materials and alloys, with the focus on minimal weight with maximum durability as well as design and fabrication compatible with the materials.

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    • 1 Second Ago
      • 5 Years Ago
      Wow that's quite a remarkable reduction. This is a pretty big car and I'm amazed it weighs about the same as an old Fox body Mustang coupe. But the added initial cost, as well as potential cost for body repairs, might outweigh the weight savings. If that makes sense.
        • 5 Years Ago
        It's not really that remarkable given what they used. An aluminum spaceframe and carbon fibre parts is going to cost a ton. Plus CFRP pieces that need to be crash tested end up costing a fortune to replace (ie. $17000 Shelby hood fiasco).
      • 5 Years Ago
      Now you can haul two extra supermodels for the same amount of fuel.
      • 5 Years Ago
      Did you guys miss a 1 in there somewhere? You said 159 hp per ton and then 11 hp per ton for the V6...

      "Compared to the V6 model, the 208 hp turbocharged 2.0-liter model has a power-to-weight ratio of 159-hp per ton, while the V6 variant trumps it by only 11 hp per ton."
        • 5 Years Ago
        Jason, I don't think I am an idiot. I was making the point that German luxury-performance cars are overweight. A point which they recognize. Also, looking at power to weight is just one measure of performance, since cars need to slow down and go left and right. A lighter car is just more fun, eg those British sports cars like Lotus that get their handling at least partially from 'lightness.'
        • 5 Years Ago
        They're saying the V6 has 11 HP-per-ton more than the 2.0T, which has 159, not that it has 11.
        • 5 Years Ago
        As in the V6's ratio is 170-hp per ton. 159 + 11, well, you get the picture
        • 5 Years Ago
        I'm pretty sure they mean the V6 model has 170-hp per ton.

        159 + 11 = 170

        get it ?
      • 5 Years Ago
      Honda Civic coupe weighs ~2500lbs. Don't worry Audi, you'll catch up. Ja Wir konnen!
        • 5 Years Ago
        The Evora is a fat pig so I don't think that would be much help here.
        • 5 Years Ago
        See...this is where Lotus could come in. Maybe a modified Evora frame? Save Audi the r&d money and probably build a better product.

        It would be great if Lotus built a sedan chassis based on the extruded then bonded technique, not for their use, but for other companies.

        Then, with all the extra money they have coming in, Lotus could lower the price of the Exige.
        • 5 Years Ago
        Wheatstraw , that would be too expensive.
        • 5 Years Ago
        You are really trying to compare a Civic to an A5? Are you an idiot?
        Guess what. A Tata Nano is lighter than a Civic. Guess they have a lot of catching up to do, huh?
      • 5 Years Ago
      Nice, a A5 that weights the same as my VW with more than double the horsepower, sounds like a fun ride.
      • 5 Years Ago
      Me likey!
      • 5 Years Ago
      Problem-the cost of that aluminum body probably places the cost of the whole car at near the V6 model. The savings are at the pump, but...
        • 5 Years Ago
        Yeah, you beat me to the post about cost.

        The price of aluminum for an entire car is ridiculous. Do this to the 2.0L A5 and suddenly you don't have a cheaper priced A5 for people to get into. Sure you get a performance improvement in all the dynamic kinetic measurements, but how are you going to price this competitively? It costs money to go out and design a smooth running 1.5L turbo to put in a luxury coupe.
        • 5 Years Ago
        Good point but you're forgetting the economies of scale. If Audi were to take this technology and then spread out the cost of it over several vehicle platforms in addition the increase of production the cost will come down.
        • 5 Years Ago
        quote from Art:
        - "Well, they have an aluminum A8. it's just a pricey car, and there's no two ways about that" -

        and yet it's right in line with its competition, the M-B S-Class and BMW 7-Series.
      • 5 Years Ago
      Alu framed A3, please. Am willing to offer either kidney or first-born, take your pick.

      (Doubt I could afford it otherwise...)
        • 5 Years Ago
        240Lbs? Isn't this an average weight for a typical American woman?
        • 5 Years Ago
        Audi quotes 3375 pounds for an A5 2.0t, so why is acticle claiming curb weight is 3130??
        • 5 Years Ago
        Remember this article posted some months ago:

        Audi claimed they made a prototype weighing 800 lb less than the production model. I made a skeptical comment then. Well, now the prototype is out of the lab, and weighs 200 lb less (not 800lb) and it is still not a production car.

        Take a guess and say how big will be the weight reduction by the time it will reach production.
      • 5 Years Ago
      So... reading between the lines... the RS5 won't need a power hike because it'll be lighter than the M3 while keeping awd? awesome. wait... 450 hp u say? more power and lighter? Even better. I'm quite looking forward to the RS5 now.
      • 5 Years Ago
      3130 lbs ???? Haha, more like 3737 lbs for the 2009 Audi A5. There is NO way the starting weight is at 3130, false information.
      Get the facts straight Autoblog.
        • 5 Years Ago
        That 3100 figure bugged me too. That's the weight of a GTI, and this is a considerably larger car than a GTI. I looked it up, and audi.co.uk has 3150 lbs for the FWD 2.0T (which must be what autoblog referenced). For the AWD 2.0T, its 3300 lbs. For the AWD 3.2L, it has 3400 lbs.

        The audiusa.com website says 3600-3700 lbs for the 2.0T models, and 3800 lbs for the 3.2L. Europe has much lower base specs than US, so all of the stuff that is standard here must add all the extra weight.
        • 5 Years Ago
        The dry-weight of the european front wheel drive A5 2.0 T really is 3130LBS. Add driver and liquids to that and it would come out at about 3350LBS.
      • 5 Years Ago
      doesn't Audi have a 2.0T in the S3 putting out 261HP? wouldn't that work better on the aluminum A5, then having the V6?
        • 5 Years Ago
        Ya thats what I was thinking.

        If they put the R20 engine in the aluminum A5, this would be a sweet car !
      • 5 Years Ago
      @john: what's "COMPOSITS"? do you mean "Composite materials"?'
      technically, straw and mud together make a composite material... man, that would an interesting car, you couldn't drive it n the rain though.
      but I kid.... Yes, composite materials would be lighter, but how much does that Aston Martin one-77 cost?
        • 5 Years Ago
        montoym , i know about that , i'm into planes and my best friend is an aerospace engineer and pilot. i meant structural parts in an aircraft, you can't replace those and the high altitude planes and fighter jets are exposed to extreme temperature variations and high stress. you can't replace those parts at a maintenance , those structural are made to last for the entire life span of said aircraft.
        • 5 Years Ago
        Vision7 , interesting , but aren't those composite materials used in the aircraft industry ? aren't planes and helicopters exposed to the same (or even worse) conditions as cars ?
        • 5 Years Ago
        quote from sparrk:
        - "aren't planes and helicopters exposed to the same (or even worse) conditions as cars ?" -

        Yes. However, planes and helicopters also have much more rigorous maintenance schedules. I'm not fully involved in the aviation industry, but I have been somewhat involved this summer and have learned a lot about it over this short time in speakign with a number of pilots with vast experience.

        Here's a link that explains(very briefly) about the maintenenace checks that all aircraft undergo.


        Particularly note the intensive nature of a D Check and make note that it occurs every 4-5yrs. Have you ever owned a vehicle which underwent even remotely the same type of check ever in its life, much less every 4yrs?

        If you wish to read more about the D Check, they also provided another link at the bottom of the wikipedia link,

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