GM Shows V-12, New Six, And More

October 8, 2002

MILFORD, Mich. — For the second time in three years, General Motors has unveiled some of its most important future powertrain products and technologies to let the world know exactly where it’s going. Why? To improve its image and head off criticism that many of its engines and transmissions are not yet world-class competitive.

In an Oct. 4 international media briefing at the company’s Milford, Mich., Proving Grounds, group vice president, GM Powertrain, Tom Stephens and vice president and general manager Powertrain Engineering Operations Ned McClurg pulled the wraps off a 500-plus-hp V-12, a new global family of “high feature” V-6 engines, upgraded OHV V-6s, expanded Displacement on Demand (DOD), six-speed automatic transmissions and a whole lot more.

It was reminiscent of another media-wooing event a few years back that previewed some of the GM technology and engines we have now. In 1999, GM Powertrain previewed its ECOTEC global four-cylinder and VORTEC engine families, the Duramax Diesel and Opel Family II Turbo and both five-speed and auto-shift automatic transmissions -- all in or very near mass production today.

Goal: global best

Stephens began by explaining his ambitious global mission (“World’s Best Powertrains”) and product and technology strategies. The product strategy involves three categories of engines: “image” (Corvette Z06, the coming V-12), “high feature” (high-tech, overhead cam, multi-valve) and “high value” (lower-cost, cam-in-block, overhead-valve).

Since research shows that 70-80 percent of buyers value performance, smoothness, quietness, economy, reliability and durability at a reasonable price -- and don’t know or care about high-tech features -- 70-80 percent of GM’s engines (by volume) will be the more affordable “high value” variety. But since the other 20-30 percent read enthusiast magazines, compare notes with others and care very much about the latest hardware and technology, that percentage of GM engines will be “high feature” to attract and satisfy that group of buyers.

At the tiptop of GM’s performance pyramid will be the “image” engines, amounting to about one percent of volume. Soon to join this exclusive club is the new all-aluminum, dual-overhead-cam (DOHC), 48-valve high-output V-12. Designed originally for the Cadillac Cien supercar concept (which apparently will not reach production), this first GM V-12 since 1937 will power one or more unspecified Cadillacs – probably an ultra-sedan and/or SUV. It will displace 7.5 liters, generate “well over 500” hp and package in the space of a large V-8.

“When you look at the luxury market and Cadillac’s future portfolio,” Stephens said, “there is a need for ultra luxury. One price of entry is an image engine such as a V-12.”

Sixes for all?

GM V-6

GM V-6

GM’s new family of all-aluminum, 24-valve DOHC V-6s, “intended to satisfy powertrain requirements for premium and high-performance vehicles across the world’s automotive markets,” will range in size from 2.8 to 3.8 liters. They will feature roller-finger followers, electronic throttle control (ETC), forged steel crankshafts, special piston-cooling oil jets, coolant loss protection software, GM’s Oil Life Monitoring System, 32-bit microprocessor, coil-on-plug ignition and iridium spark plugs. First to debut will be a 255-hp 3.6-liter version incorporating variable intake and exhaust valve timing (cam phasing) to optimize starting, idle, low-rpm torque and high-rpm power as well as emissions and economy.

The upgraded OHV V-6 family will expand to include displacements from 2.5 to 3.9 liters. First to debut will be a 240-hp 3.5-liter version for the ‘04 Chevy Malibu. Thanks to an advanced powertrain control module (PCM), improved fuel injection, exhaust manifold, accessory drive, cooling and sealing, plus a new-design catalytic converter, it will be smoother, quieter, more powerful and more fuel efficient than earlier generation OHV V-6s.

Some media members (“high-feature” types themselves) questioned why GM would continue to invest in “old-tech” OHV engines when competitors have long since gone to high-feature powerplants across the board. Stephens countered that they should be thinking “good” vs. “bad,” not “old-” vs. “new-tech.”

“Since the vast majority of customers don’t care about features,” he asserted, “we can do larger displacements with better performance and fuel economy at lower cost than our competitors.” An engine’s level of technology is defined by much more than its valvetrain, and “efficiency levels of new-tech pushrod engines come very close to those of OHC. Another advantage is packaging, and you can get modern OHVs to rev like OHC engines. No one would call today’s Corvette engine ‘low-revving.’”

Another major advantage of OHV design is the ability to incorporate fuel-saving cylinder deactivation, which GM calls Displacement on Demand. Already slated to debut on some GM V-8s in 2004, DOD (which deactivates half of the cylinders by closing both intake and exhaust valves under light load conditions) will expand to the updated OHV V-6 family in 2005. By 2008, DOD will be featured on all GM OHV V-6s and V-8s in more than two million vehicles.

“It’s a very simple, elegant solution on two-valve-per-cylinder, OHV engines,” Stephens explained. “With four-valve engines, you have to close all four valves in sequence, and with hardware in the head rather than in the valley of the block.” With DOD planned for high-volume family cars, light trucks and SUVs, he added, “we’re making our most popular vehicles sold in North America even more fuel efficient, and without any sacrifice in performance.” Economy improvements should range from 8-20 percent, depending on driving conditions.

Diesel aspirations and hybrid hopes

Also soon-to-come is a new ECOTEC CDTI 1.3-liter, 16-valve four-cylinder turbodiesel for European and Latin American markets. This 112-hp engine, the first product born of the Fiat-GM Powertrain joint venture, incorporates many advanced technologies including next-generation, multi-jet common-rail fuel injection and variable-geometry turbocharger. Introduced in an ECO sports car concept at the ‘02 Paris Auto Show and reaching production in ‘03, it will meet Euro 4 emissions with lower noise levels and 10 percent better economy.

A bit over two years away is GM’s new family of six-speed Hydra-Matic transmissions, which will provide 4-7 percent higher performance and 1-4 percent higher economy in a wide variety of rear- and all-wheel drive cars and trucks. Features include an enhanced performance algorithm shift, clutch-to-clutch shifting, automatic grade braking, tapup/tap down Driver Shift Control and an integrated center differential for full-time AWD Capability.

Stephens’ technology strategy involves increased power, torque and economy – along with reduced emissions -- across the board. He is targeting 60-plus hp per liter with increased applications of cam phasing, variable displacement, super- and turbocharging and much more. For diesels, 80-plus hp per liter is the target, along with reduced noise, vibration and emissions, through reduced compression ratios, improved common rail injection and turbocharging. He adds that advanced diesels “look good” to meet future European emissions standards but “don’t look viable” for the U.S. “We have diesels in our portfolio that would work very well, but so far we can’t meet U.S. emissions requirements beyond ’06. We’re still working on it, but we’ll need low-sulfur diesel fuel and a regulation change to make them work here.”

GM has been criticized for not having hybrid-electric cars on the market to counter Toyota’s Prius and Honda’s Insight and Civic hybrids. Stephens described GM’s approach of hybridizing the highest-consuming vehicles first as “intellectually honest.” GM’s soon-to-debut 13,000 diesel-electric hybrid buses, for example, can save as much fuel as a half-million hybrid small cars. GM will introduce parallel hybrid light trucks, offering a 12 percent composite fuel economy improvement (plus a portable generator) in ‘04 and will follow later with hybrid cars.

Questioned on GM’s fuel cell development, Stephens said, “the only solution for zero emissions and 2X fuel economy is a hydrogen economy and fuel cell power. We need help with developing the infrastructure, and we need to keep working on interim technologies such as hybrids, since advancements in hybrid-electric technologies such as electric motors and control systems can be applied to fuel cell electrics later.”

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