Cadillac has announced a new generation of V-6 engines, led by a Twin Turbo V-6 that will be one of the industry’s most advanced six-cylinder gasoline engines. It leverages the latest technology to balance efficiency, performance and refinement in the upcoming CT6 luxury performance sedan.
The Cadillac 3.0L Twin Turbo is designed to achieve new thresholds of refinement and specific output for the brand’s new prestige luxury sedan, which makes its world premiere March 31, at the New York International Auto Show. Production begins late this year at General Motors’ Detroit-Hamtramck Assembly Plant.
Peak output is estimated at 400 horsepower (298 kW) and 400 lb-ft of torque (543 Nm), making it one of the most power-dense V-6 DOHC engines in the world, developing 133 horsepower (99 kW) per liter.
The 3.0L Twin Turbo is the only six-cylinder engine to combine turbocharging with cylinder deactivation and stop/start technologies to conserve fuel. Cadillac expects the combination to enhance fuel economy by up to an estimated six percent. Cylinder deactivation temporarily deactivates two of the cylinders in light-load driving conditions to enhance efficiency and seamlessly reactivates them when the driver demands full power.
With the stop/start system, the 3.0L Twin Turbo is shut down in certain driving conditions such as stop-and-go city driving to reduce fuel consumption, automatically restarting when the driver takes his or her foot off the brake pedal.
“Cadillac’s elevation on the world stage is driven in great part by its advanced powertrain technology and the all-new 3.0L Twin Turbo powers past the traditional segment leaders with higher degrees of the performance and refinement their reputations were built on,” said Rich Bartlett, assistant chief engineer.
The Hydra-Matic 8L90 eight-speed automatic transmission transfers the 3.0L Twin Turbo’s power to the CT6.
Similar to the turbo system in the track-capable Cadillac ATS-V, the new 3.0L Twin Turbo features turbochargers with lightweight, low-inertia titanium-aluminide turbine wheels and an efficient, patented low-volume charge-air cooler, which contribute to optimal boost production and more immediate power delivery.
The advanced, low-inertia turbochargers enable the engine to sustain peak torque from 2,500 rpm to 5,000 rpm, giving it a broad torque curve that is conveyed to the driver through a feeling of responsive, sustained power across the entire rpm band.
“Torque is the pulling power of an engine and the new 3.0L Twin Turbo delivers it with confidence-inspiring smoothness and progression,” said Bartlett. “In fact, the potency of the torque across the rpm band is matched only by the satisfaction of the horsepower created as those revs climb quickly to 6,500 rpm.”
All-new architecture
Cadillac’s new 3.0L Twin Turbo is part of a new generation of technologically advanced V-6 engines, which includes a new version of the 3.6L naturally aspirated engine employed for years across the brand’s model range. Each features new structural and combustion elements designed to complement higher performance and greater efficiency with exceptional quietness and smoothness.
The 3.0L Twin Turbo is up to 5 dB quieter than the Audi 3.0L TFSI engine, while the 3.6L is up to 4 dB quieter than the Infiniti 3.7L V-6.
Features shared by the 3.0L Twin Turbo and 3.6L:
- Stronger, stiffer aluminum block with increased structure in the bulkheads for superior rigidity
- Tough, refined rotating assembly with a stiff forged-steel crankshaft, friction-reducing polymer-coated pistons and strong high-copper-content, sinter-forged connecting rods
- New four-cam phasing system with intermediate park technology that enhances efficiency by enabling late inlet valve closing in certain conditions
- All-new, patented “targeted” cooling system that provides strategic cooling of the engine’s hottest areas while simultaneously fostering faster warm-up, which enhances efficiency
- New cylinder heads that enhance combustion performance and include direct injection and feature integrated exhaust manifolds
- Revised, simplified timing drive system with cushioned chain sprockets contributing to quieter engine operation
- All-new oiling system moves the pump inside the block for quieter operation. The two-stage oil pump also enhances efficiency.
Unique foundation
While the 3.0L Twin Turbo is based on the same, all-new architecture as the naturally aspirated 3.6L V-6, it incorporates specific components and features to support the load and cylinder pressure characteristics unique to a forced-induction engine.
Its 86mm bore specification is about 10 percent smaller than the 3.6L, while both engines share an 85.8mm stroke. The smaller bore reduces the size and consequentially the weight of the pistons in the 3.0L Twin Turbo, making the most of the rotating assembly’s geometry to match the quicker rev capability enabled by the low-inertia turbochargers’ quick spool-up.
“With nearly zero turbo lag and a commensurately low-inertia rotating assembly, this engine climbs the rpm ladder and produces power on demand,” said Bartlett. “Its performance is more than just the maximum output – it’s how it is delivered and the new 3.0L Twin Turbo delivers it with smoothness and precision.”
The smaller bores also allow larger water jackets between the cylinders, which helps maintain optimal combustion temperatures across the rpm band and during sustained high-load, max-boost performance.
Both of Cadillac’s new V-6 engines will be produced at GM’s Romulus Powertrain Operations assembly facility, near Detroit, which received a $540-million investment to build the next-generation V-6 engines.