The German automaker Audi has just revealed details about an aluminum prototype lightweight A5 Coupe that uses the same space frame architecture that is used in the Audi R8 super car and TT sports coupe. Audi’s goal is to improve the overall performance of the midsize coupe by reducing its curb weight, by 242 lbs to be exact. When Audi’s engineers reduce the mass of the A5 coupe, they allow the engine to to breathe easier, the brakes to work less and the suspension to be tuned more precisely; making the four ringed luxury car a better all around performance machine.

Audi RS5 renderings
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The prototype Audi A5 is based on the steel bodied production car, replacing the bulkier design with the bespoke aluminum Audi Space Frame that reduces the weight of the prototype from 3,130 lbs to 2,888 lbs. While it’s currently powered by a 2.0 Liter TFSI four cylinder that makes 211 HP, in the interest of weight and economy, the lightweight chassis would make a great candidate for the foundation of a very nice future super car from the 100 year old four ringed automaker.

With all the current talk of Audi RS5s in America in the near future, it looks like this prototype is a test mule for a 450 HP V8 powered 2011 RS5. Not only would the lightweight construction make the future RS5 an even better handling machine, but hopefully Audi’s power train engineers have sorted out the new A5’s transaxle layout so that the engine can sit a bit further back in the body. Just imagining an aluminum Audi RS5 with its blistered fenders and gills in the front bumper only hint subtly at the beast that would lie beneath. Another interesting fact about an aluminum bodied FSI V8 sports car would have over twice the horsepower, so an aluminum B segment RennSport would have twice asa much potential to push around all that weight.

Press release after the jump.

  • 2009 Audi A5 aluminium bodied prototype
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Press release

2009 Audi A5 aluminium bodied prototype
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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.

What do you think?
Show Comments


  (858) posted on 10.11.2010

240Lbs? Isn’t this an average weight for a typical American woman?

  (345) posted on 10.6.2010

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.

  (512) posted on 02.11.2010

@ Euginewoods - yes it does affect the handling, audi know how to handle that problem if you want more grip change you rubber and make your tire wider also make the spring stiffer to cut easily through tight corners.

  (570) posted on 02.3.2010

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.

  (555) posted on 01.27.2010

if they make the body all aluminum, I think the handling of the car will be affected, because the body will be lighter.

  (1023) posted on 01.18.2010

aluminum is light and tough plus it decays less than the regular car steel body, and it can accelerate faster than the regular a5 plus make it’s handling superb.

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