Audi Q7 to Get 500-hp V-12 Diesel

The “race on Sunday, sell on Monday” mantra lives on at Audi AG, as the German auto maker prepares to unveil its new 500-hp Q7 V-12 TDI cross/utility vehicle at the Paris auto show later this month.

Benefiting from a marketing and development effort that earlier this year resulted in Audi becoming the first auto maker to win the prestigious 24 Hours of Le Mans endurance race with a diesel-powered vehicle, the new Q7 V-12 is the first production passenger vehicle to feature a 12-cyl. diesel.

Audi Q7 V-12 TDI is first 12-cyl. diesel passenger vehicle.

Rated at 500 hp and 738 lb.-ft. (1,000 Nm) of torque – available between 1,750 rpm and 3,000 rpm – the new 6L twin-turbo mill also is the most powerful production diesel engine ever produced, Audi says.

Initial figures for the 5,500-lb. (2,495-kg) CUV are impressive: 0-62 mph (100 km/h) sprints in 5.5 seconds; an electronically limited top speed of 155 mph (250 km/h); and a combined fuel economy rating of nearly 20 mpg (11.9 L/100 km).

Although relatively close in size and output to the 5.5L, 650-hp V-12 employed in the R10 TDI Le Mans racecar, the new Q7 engine actually is a member of Audi’s 6-, 8- and 10-cyl. diesel V-engine family.

A compacted graphite iron (CGI) engine block, opposed to the R10’s aluminum unit, donned with aluminum cylinder heads forms the basis for the new engine.

A 60-degree cylinder angle reduces inertia from internal components and is the main differentiator between the V-12 TDI and Audi’s other 90-degree turbodiesel V-engines.

CGI, which Audi already uses in its European market 3L V-6 and 4.2L V-8 turbodiesels, is 40% more rigid and 100% more fatigue-resistant than cast iron. The material also allows for a 15% weight savings over cast iron, the auto maker says.

Internally, a 16:1 compression ratio is achieved through forged aluminum pistons and connecting rods, which share the same bore and stroke measurements as Audi’s 3L V-6 TDI. Overall length for the V-12 is only 6.5 ins. (17 cm) longer than the 4.2L V-8 TDI.

A new chain-driven valvetrain assembly is employed, as is a new high-pressure, common-rail fuel-injection system utilizing piezo-hydraulic-electric injectors. For the V-12, injection pressures are up from Audi’s current 23,206 psi (1,600 bar) to 29,008 psi (2,000 bar).

Six-liter V-12 TDI makes 500 hp and 738 lb.-ft. of torque.

Other features include twin, variable geometry turbochargers producing up to 38 psi (2.6 bar) of boost; twin charge air coolers; and a double-flow exhaust system with twin particulate matter filters.

In addition to improving the common-rail injection system, Audi says it focused heavily on a new exhaust gas re-circulation system in an effort to meet Euro 5 emissions standards taking effect in 2010. It is not known if additional exhaust aftertreatment systems will be used to meet upcoming Tier 2 Bin 5 emissions regulations in the U.S.

Harnessing the V-12’s prodigious power is a strengthened 6-speed Tiptronic automatic transmission and Quattro all-wheel drive.

On the road, Audi says the new Q7 V-12 will have a unique and impressive exhaust tone. However, given the R10’s whisper quiet performance on the racetrack, visual cues – and gross displays of acceleration – likely will be the only ways to differentiate the V-12 TDI from lesser Q7s.

Major exterior changes include aggressive front and rear fascias; a chrome-plated, single-frame horseshoe grille; and larger brakes, wheels and tires.

Details about pricing and availability currently are unavailable, but a rollout in the 2008 timeframe is expected.

The Paris auto show is open to the public Sept. 30-Oct. 15.

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