2014 Audi S5

2014 Audi S5

2014 Audi S5

2014 Audi S5

The current Audi S5 coupe is gorgeous, fast, and luxurious, but at over 3800 pounds, it's not dainty. And the upcoming 2010 S5 cabriolet will weigh about 4300 pounds--more than a lot of mid-size SUVs--so forgive us for thinking Audi product planners were being intentionally ironic when they spoke at the car's launch about their green philosophy and success in downsizing. They conveniently neglected to mention weight and focused on their powertrain strategy: a far more efficient supercharged 3.0-liter V-6 replaces the naturally aspirated 4.2-liter V-8 in the S5 cabriolet and S4 sedan for 2010, with the S5 coupe getting the new engine for 2011. These cars are claimed to achieve the same acceleration as the V-8 models while using 20 percent less fuel.

Still, any idiot knows you can only get so far with engine downsizing in a performance car that weighs more than two tons. So we sat down with Michael Dick, Audi's global head of product engineering, and asked him about how he squares the company's stated smaller-is-better credo with the reality of its hefty cars.

We expected to hear some mumbo-jumbo about how safety standards and consumer expectations for features and refinement dictate ever-growing curb weights, but Dick's response shocked us: Audi is currently testing a prototype of the next-generation S5 that weighs 880 pounds less than the current car. He outlined the ongoing increase in the use of aluminum, magnesium, and high-strength steel as a main reason behind the mass reduction. The current TT's chassis is 69 percent aluminum, and the next-generation A6 (probably due in 2011 or 2012) will have an even higher proportion, Dick says. The amount for the next A4/A5/S4/S5 will be higher still when they debut, likely as 2014 models.

Dick also said that the supercharged 3.0-liter V-6 is an "intermediate step" for Audi. The next S4 and S5 will have lighter turbocharged four-cylinder engines. We can look at the TT lineup for direction: the base TT in the U.S. has a 2.0-liter turbo four that makes 200 hp. The TT S has the same basic engine, but makes 265 hp with beefed up internals and a bigger turbo. Future S4 and S5 models will have about 20 percent less weight and up to 30 percent less engine displacement than the current S5, making combined fuel economy in the mid to high 20-mpg range likely.