Reviews & Road Tests
Driven: 2004 Audi A8 4.0 TDI
By by: George Achorn, photos by author
Nov 16, 2004, 20:26

In a world where global energy reserves appear to be constantly dwindling, the world’s largest automotive market – the United States – sits at the center, pulled apart by two divergent philosophies on the best methods of conservation. In one corner, we have the Far East, specifically Japan, with their growing gasoline hybrid offerings. In the other corner is Europe, with its training in diesel a specialty and where a large chunk of the market of cars sold is now fuel-sipping diesels. With such heavy market penetration of diesel technology, it was only a matter of time before high-powered and even sporting offerings began to surface over there.

Enter the Audi A8 4.0 TDI. The pride of Ingolstadt, Audi’s Q-ship might be large in size, but its aluminum construction assures it remains light on its feet and floating like a butterfly on its adjustable air-suspension. However, the heart of this champ – Audi’s new 4.0 TDI powerplant – focuses more on stinging like a bee, with the conservation to make it last round after roundtrip, ranging from weekend getaway to grocery store alike before even thinking of stopping for a refuel.

When one thinks of a toned boxer in the automotive world, the traditional first thought hasn’t been of diesel. Even in Europe, where the range of diesel products has grown most, diesel automobiles were chosen for rational conservation with little other thought of performance or sexiness as recently as just a couple years ago. Diesels used less fuel and offered healthy tax breaks to those who chose them in many of the European markets and as such, performance was a low priority, if a priority at all, for buyers.



However, technologies are improving, engine design and components such as Bosch’s second-generation common rail system have augmented them to a much more desirable place.

Audi’s svelte new engine starts with a 4.0-liter V with four valves per cylinder head and Bosch common rail system, with one rail per cylinder bank. This new common rail system injects fuel through seven-hole nozzles at a formidable 1,600 bar of pressure, with the ability to inject fuel several times per combustion cycle, resulting in reduced exhaust emissions and engine noise. At low speeds, the engine operates with double pilot injection (for improved power?), while at higher speeds it goes to single pilot injection (for improved economy?).

To augment power even further, Audi has added two turbochargers, one at each cylinder bank. Each turbo has a variable geometry turbine allowing for exhaust optimization depending on engine speed. Output from each turbo is cooled by two air-to-air intercoolers. For a diesel, boost builds to a surprisingly lofty 2.2 bar, managed by Bosch’s EDC16 engine management.

Audi’s 4.0 TDI is a technological tour-de-force, packing a punch with 272 bhp at 3750 rpm and 479 lb-ft of torque from 1800 to 2500 rpm. Power is transmitted through Audi’s latest 6-speed Tiptronic transmission mated to their bulletproof Torsen-based quattro system, allowing the A8 to pack a wallop and dance away from any stoplight in the kind of hurry one wouldn’t initially expect from a big diesel-powered car.



With the new Tiptronic, drivers can indulge in other features Audi sportingly allows with their 4.0-liter diesel, such as Sport-mode shift patterns and steering wheel-mounted butterfly shift controls (North American RS6 and TT DSG owners will find thes familiar) Not exactly frugal and conservative, eh?.

Zero to 100-km/h (62mph) comes in a claimed 6.7 seconds, bettering the gasoline-powered likes of the BMW 735i, the Mercededes-Benz S430, Volkswagen Phaeton 4.2 and even the Phaeton with Volkswagen’s own 5.0-liter V10 TDI. The diesel-powered A8 will pull hard up to triple digits with ease and bounce off of the 155 mph governed top speed limiter.

Like all good fighters, the A8 is deceptively fast. Drop the hammer and the car hunkers down, pulling hard and steadily on up to heavy-weight speeds in a fashion that you’d expect from a German-luxo Q-ship and often don’t get from the diesel side of the ring.



With performance cars such as the TDI-powered SEAT Ibiza Cupra on the European market as well as Volkswagen’s stump-pulling Touareg V10 TDI now available in the States, serious performance figures out of Audi’s 4.0 TDI probably aren’t that hard to fathom and might even be assumed by those more familiar with other-market diesels. However, one of the truly enticing qualities of the 4.0 TDI might not be how hard it pulls, but how refined it remains in the process.

We were pleased to find that starting our European-market A8 with its uber-cool center-console mounted keyless start button offered no rumble to life as with the typical diesel gutteral clatter. Also, there’s no foot-massage vibrating gas pedal as is common on even higher-end diesels such as BMW’s latest generation 3.0d. Instead you get a refined pedal feel and audible bass-like humming that gives way to what might even be called a menacing growl with just a hint of diesel chatter under more aggressive acceleration. While it might fall a bit short of the svelte and sexy song of a 4.2-liter S4, it’s much more impressive than other diesels we’ve seen before. Even better, settling in on the highway, one hardly notices much of an engine note at all.

To the competition, Audi can take a line from a previous champ – Mohammed Ali.

“Rumble young man rumble.”

In the luxo-diesel segment, Audi has certainly drawn the line in the sand for its competitors.

With various trips to Europe and exposure to Capitol Hill diesel ride and drives, we’ve yet to see a diesel that is more refined and less a rumbler than Audi’s 4.0 TDI. Though not as powerful as Volkswagen’s V10 TDI, the 4.0 feels almost as muscular and is more refined.



With all of this technology, sporting hardware and refinement, one might lose sight of the core reason for diesel ownership. Lest we forget, diesel technology has been adopted for its conservative appetite for fuel. Audi claims combined fuel consumption of 28.8 mpg, compared to the 23.5mpg combined mileage for the 4.2-liter gasoline-powered A8L currently offered in the United States.

And, back in the USA where the gasoline-powered A8 is the reigning champion in Audi's four-ringed lineup, one has to wonder just how long it might be before we get an offering like the 4.0 TDI. Currently, Japanese hybrids tend to draw all of the fuel conservation attention. However, there’s an active lobby for diesels as there’s a core competency that the Europeans would like to cash in on. If Bosch and other suppliers can engineer a way to make diesels meet stringent US particulate emissions laws – a typical drawback for diesel technology – the way could be paved for cars like the A8 4.0 TDI to come to our market. With large size and boatloads of power and torque, one can assume they’d be much more attractive to mainstream American consumers than econoboxes like the Toyota Prius. After all, it was the larger and more powerful cars such as the A8 4.0 TDI, Touareg V10 TDI and BMW 730d that drew the most attention from Senate staffers at the aforementioned Capitol Hill ride and drives.

With particulate level emissions coming down and fuel prices going up, one can easily see how the bell has rung for the first round of diesel-powered automobiles to seriously enter the US market. Progressing into following rounds, the A8 4.0 TDI stands ready to dance into the ring and ready for a fight.



Cirrus SR-22 Single-Engine Personal Aircraft

Another fast mode of transportation that could also be called a revolutionary champion of its segment is the SR22 single-engine aircraft sold by Cirrus Design Corp. Introduced in 2000, the plane has been the best-ever selling model for the relative newcomer of a company in the personal aircraft industry.

Cirrus’ SR22 sets new standards in the single-engine personal aircraft segment and features advanced avionics, a 310-hp engine, power redundancy and even a parachute that brings the entire plane down at a survivable speed in an emergency.

Powered by a Teledyne Continental Motor IO 550, the plane, as mentioned, has a dual 24-volt electrical system which provides redundancy to the control panel without air-powered gyro instruments – not typically standard fare in the single-engine plane market. That means two alternators, two regulators, two batteries and two electrical buses. You’d have to lose main alternator, main battery and secondary alternator before you go to the final battery, which would still mean 45 more minutes of power.

Essential bus-powered equipment include an electrically powered attitude indicator, turn coordinator, S-Tec System Fifty Five X autopilot, and primary navigation computer. All this redundancy provides ample peace of mind.

Inside, there's a well-designed cabin, with comfort in mind. Virtually anything the pilot might need is within easy reach of the left seat. The Cirrus’ side-mounted yoke – with its entire grip rotating around the axis of the control column for roll control, the column moving forward and backward for pitch – is also somewhat unique to its segment. The design keeps the instrument panel relatively uncluttered and lends to the functionality of the interior’s design.

Rear seat legroom is good for its class. There’s also 32 cubic feet of luggage space and, since we’re talking airplanes, that space is rated for 130-pounds of baggage.

The SR22 itself weighs in at 2,250 lbs., though on the tarmac its maximum gross weight is 3,400 lbs. and most of the additional weight comes from 646 lbs. of fuel. The rest of the weight is factored in for a couple of adults, a couple of children and the aforementioned baggage.

Up in the air, the Cirrus will cruise at just over 180 knots – roughly 197 miles per hour, getting 10.5 nautical miles per gallon according to Cirrus.

One of the most unique aspects of the Cirrus SR22 and another added safety feature is the Cirrus Airframe Parachute System (CAPS). Designed, tested and certified by Ballistic Recovery Systems, Inc. (BRS) of South St. Paul, MN, CAPS uses a small rocket motor to break through a thin section of the fuselage and jettison the parachute from its container.

In an emergency, a pilot need only open an overhead cover, remove a safety pin and pull a handle. Within 1.5 seconds of pulling the handle, Cirrus claims the chute will be at full stretch, with the canopy opening within a few more seconds. Deployed, the aircraft will descend at about 1,700 feet per minute.

Impacting with the ground, the plane has been designed to crumple and save the lives of its occupants. Landing gear deforms first, followed by the intended crushing of the seats. Total impact forces have been designed in order for passengers to walk away from a crash, perhaps with some bruises, but on their own two feet. The plane on the other hand will be totaled.

If you’re in the market for a high-performance single-engine aircraft, the Cirrus SR22 is most definitely a strong contender. Considering the planes power, ergonomics and safety, there are few competitors in the market that offer the value of the Cirrus and none offer a parachute safety system like the SR22.

More info:
Cirrus Design

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