Hyundai Motor Co. Ltd. has big plans for its new 4.6L Tau V-8.

Representing a $260 million investment and the work of 100 engineers over 48 months, some critics have questioned why the South Korean auto maker needs a V-8 at all. Now, the rationale is becoming clear, and it runs to the core of the auto maker’s aggressive global ambitions.

The Tau’s destiny is not just to be an option for Hyundai’s Genesis luxury sedan and Kia Borrego SUV; it is the auto maker’s launching pad into the world’s luxury and performance markets and into the U.S. light truck segment – if that beleaguered sector ever recovers.

Still viewed as a small producer of entry-level cars by many U.S. consumers, Hyundai actually is a global powerhouse. Together with its Kia brand, it is the sixth best-selling brand in the world and has a commanding 75% share of the domestic market in Korea.

The auto maker employs 8,000 engineers and scientists at its Namyang research-and-development center outside Seoul. Its engine development center boasts 250 dynamometers, one of the largest clusters of such testing equipment in the world.

Hyundai now badly wants not just the revenue but also the respect that goes with producing a world-class luxury car and V-8.

The highly praised 4.6L V-8, which recently marked Hyundai’s first appearance ever on the Ward’s 10 Best Engines list, is the first member of a growing engine family based on the same architecture, says Hyundai Vice Chairman H.S. Lee.

A 5.0L version of the V-8 goes into production in June alongside the 4.6L in Ulsan, South Korea. A supercharged 450-hp variant of the 4.6L also has been developed for performance applications, and a larger 5.5L member of the same engine family is waiting in the wings.

The 5.0L will power a long-wheelbase version of Hyundai’s new Equus sedan, which debuts in South Korea later this year, following a standard-size Equus bowing at the end of February. Based on the Genesis rear-drive platform, the stretched “limo” is similar in size to a BMW 750Li or long-wheelbase Mercedes S-Class.

Unknown in the U.S., the Equus is Hyundai’s flagship in South Korea. Often used as a limousine to transport captains of industry and heads of state, it is a key part of the auto maker’s corporate self image.

A notch above the Genesis, it will be sold around the world, including Europe, China and the Middle East. In about two years, the auto maker will offer the car in America, as well, Lee says.

The outgoing Equus has been out of date for some time. Its aged V-8, based on an old Mitsubishi Motors Corp. design, has been a sore point for Lee and his colleagues for years.

Lee is an engine designer who has overseen the development of the auto maker’s recent powertrains and still has gasoline in his blood.

He was president of Hyundai’s corporate R & D division before recently being promoted to vice chairman and headed powertrain development before that. “I no longer design engines myself, but even these days I drop by the design office or test lab to give them some idea of what I am thinking,” he says.

For years, Lee dreamt of creating a world-class V-8 to replace the dated engine in the Equus.

“As a global manufacturer, we were using a Mitsubishi design in our flagship vehicle, which doesn’t make sense,” Lee says. “The engine was very old and underpowered, 270 hp from 4.5L.”

“Since we needed a V-8 engine, we needed to do our best to make it a world leader, so we tried that and we were very successful,” he says with a smile.

Hyundai likes to point out the Tau’s 375 hp bests the output of comparatively sized V-8s in Lexus, Infiniti and BMW brand models priced thousands more than the base price of the $38,000 V-8 Genesis.

The Tau also trounces the specific output of V-8s offered in more moderately priced products from Detroit, such as the 5.7L Hemi in the Chrysler 300C and the 6.0L V-8 in the Pontiac G8. It can burn regular grade gasoline, too, at a sacrifice of 7 hp and 9 lb.-ft. (12 Nm) of torque.

U.S. acceptance has been strong. Until the new-vehicle market collapsed during the final two months of 2008, the take rate for the V-8 option on the Genesis was running 30% to 40%, instead of the 20% Hyundai marketers were anticipating.

Winning the North American Car of the Year Award in January has added credibility, as well.

Performance vehicles and the light-truck market are other areas where the Tau will be tapped to create growth. Lee will not say what future vehicle (or vehicles) will get the supercharged engine. “It depends on the market and whether we can justify the additional cost and power,” he says, adding the U.S. likely would be the main market for such a big, brawny engine.At the Specialty Equipment Market Assn. show last fall, Hyundai showed off an RKSport Genesis sedan concept powered by a supercharged version of the Tau, producing 460 hp and employing cylinder deactivation.The 5.5L variant primarily was designed for a U.S.-built pickup truck that now is on hold, Lee says.

“We postponed the pickup truck project. We don’t know when we can resume it.”

Direct gasoline injection, variable valve lift and cylinder deactivation all are expected to be added to future versions of the engine, but insiders will not say exactly when.

Asked what he is most proud of about the engine, Lee says it is the successful combination of power, efficiency and smoothness. That was accomplished with a relentless focus on reducing friction and weight within the engine, he says, noting numerous coatings were used on pistons and other parts to minimize friction.

“We tried many things to make the engine light,” Lee says. “Hollow crankshaft, hollow cams; you name it. And everything was optimized with CAE (computer-aided engineering) to keep piston mass and connecting rods very light.”

For controlling cost, Hyundai has a philosophy of putting more effort into engineering than trying to solve problems with advanced materials.

“With very precise engineering, we can eliminate special materials, which usually are very costly,” Lee says. (Hyundai) engineers have to work a little more than our competitors, but then we can save and end up with better performance.”

Despite Hyundai’s move into powerful luxury vehicles, Lee says the auto maker’s recently announced goal to achieve corporate average fuel economy of 35 mpg (6.7 L/100 km) by 2015 will not be affected.

“That is a tough target, five years ahead of the (current U.S.) regulation. We are working very hard to improve our fuel efficiency.”

In addition to developing hybrid-electric, plug-in hybrid and fuel-cell vehicles, a move to more efficient gearboxes is in the works, including 8-speed automatic transmissions coming shortly for both the Genesis and Equus.

dwinter@wardsauto.com