Cadillac Chases Autobahn Eaters With CT6 V-Sport

The CT6 V-Sport will retain its refined ride, GM says, and focus on a niche of luxury buyers who want the creamy, seemingly endless power only a V-8 can deliver.

James M. Amend, Senior Editor

March 21, 2018

6 Min Read
Cadillac TwinTurbo V8
Cadillac Twin-Turbo V-8.

DETROIT – Cadillac gets a jump on next week’s New York auto show buzz by revealing an all-new twin-turbo V-8 engine bound for a high-performance treatment of the CT6, a flagship sedan for the General Motors luxury brand.

The CT6 V-Sport joins the slightly smaller CTS V-Sport midsize sedan and XTS V-Sport large sedan to don the V-performance nomenclature and corresponding design elements. Like its stablemates, the CT6 V-Sport draws motivation from a big boosted engine, but whereas the others leverage 6-cyl. units the CT6 uses an 8-cyl. closely emulating those found in large, Autobahn-eating Mercedes-Benz, BMW and Audi 4-door cars.

Cadillac also sells the ATS V-Series small sports sedan and CTS V-Series outfitted with a blown V-6 and V-8, respectively, but those cars are tightly wound to target racetrack enthusiasts. The CT6 V-Sport will retain its refined ride, GM says, and focus on a niche of luxury buyers who want the creamy, seemingly endless power only a V-8 can deliver.

“Cadillac V-Sport is the embodiment of our passion to deliver an exhilarating driving experience without compromises,” Cadillac President Johan de Nysschen says in a statement. “The all-new CT6 V-Sport provides the perfect balance of design and technology with impressive power.”

The 4.2L twin-turbo V-8, a clean-sheet design three years in the making and exclusive to Cadillac, makes an estimated 550 hp and 627 lb.-ft. (850 Nm) of torque. A detuned version with an estimated 500 hp and 553 lb.-ft. (750 Nm) of torque also will be offered. The engines are mated to a Hydra-Matic 10L90 10-speed electronically controlled automatic transmission and all-wheel-drive only. Fuel economy and emissions ratings will come later.

Jordan Lee, chief engineer on the engine, admits GM could have achieved similar output from a smaller V-6 to match the Germans on paper, but would not have equaled them in spirit.

“A lot of it has to do with character,” Lee tells journalists during a sneak peek of the V-8 here. “We wanted elegant performance and thrust all of the time.”

He adds of the rival Mercedes AMG GT R, BMW M5 and Audi RS 6: “They do it for the same reason we do.”

Like those competitors, the small-displacement Cadillac V-8 employs a “hot V” design, where the twin-scroll turbocharger and electric waste gate are mounted in the valley between the aluminum cylinder heads to minimize turbo lag and overall engine packaging. The catalytic converters also are nestled inside the V.

An aluminum cylinder block houses a rotating assembly consisting of a forged steel crankshaft, forged steel connecting rods and high-strength aluminum pistons. Relatively small, 86-mm cylinder bores allowed engineers to reduce the size and weight of the pistons, which optimizes the engine’s geometry to match fast-revving turbo boost and deliver lightning-quick responsiveness and power across the rpm band.

Torque delivery focuses on the low- and mid-range rpm band, GM says, with 90% of peak pull available at 2,000 revolutions. It continues through 5,200 rpm for the feel of a bottomless power reserve, the automaker says.

Key technologies include gasoline direct injection and active fuel management, where four of the engine’s cylinders are deactivated under light loads to improve fuel economy. GM has a next-generation cylinder-deactivation system coming out with the capability to run between one and eight cylinders depending upon load, but the timing of the Cadillac engine was too far ahead to get the latest version.

Firing order for the cylinders is 1-5-4-3-6-8-7-2 (1-4-6-7 with AFM engaged).

GM places four oil jet assemblies within the block to aid in cooling and uses a variable-displacement vane oiling system to match oil supply with engine load for greater efficiency. Stop/start technology also improves fuel economy.

The Cadillac V-8 strikes an historic note, too. Its DOHC design, which includes a chain-driven valvetrain, breaks with a long tradition of big GM engines employing an overhead valve approach. Commonly known as the small-block V-8, the OHV, or “pushrod” engine, is legendary for making big power from a compact package. The engines have powered GM sports cars, luxury cars, SUVs and pickups for decades.

The engines will be hand-built at GM’s Bowling Green, KY, Performance Build Center, a part of the Chevrolet Corvette assembly plant where the Corvette Z06 LT4 small-block V-8 also is individually assembled. Each of the Cadillac engines will receive a nameplate with the builder’s name.

The ’19 CT6 V-Sport ushers to market a makeover of the entire Hamtramck, MI-built CT6 lineup incorporating the latest Cadillac design language featured on the critically acclaimed Escala concept car. The V-Sport features a bold dark front with a large V-inspired mesh grille. New horizontal LED headlamps with strong vertical signatures nod to a longtime Cadillac styling cue.

The CTS V-Sport adds lower- and rear-aero components, as well as a Gloss Black side window for a stealthy profile. The car rides on darkened 20-in. V-Sport wheels with summer-only rubber. The suspension is tuned for improved roll control, cornering capability and steering response. A specially designed Brembo 19-in. brake system provides stopping power, while active valves were added to the exhaust system to improve the sound character.

The CT6 V-Sport arrives at U.S. Cadillac dealers in the first half of next year, with rollouts in Canada and the Middle East closely following. Pricing will be released closer to launch.

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’19 Cadillac 4.2L Twin Turbo Specifications

Fuel Delivery

Gasoline direct injection

Power (SAE net)

550 hp @ 5,700 rpm

Torque

627 lb.-ft. (850 Nm) @3,200 rpm

Bore x Stroke (mm)

86 x 90.2

Compression ratio

9.8:1

Block configuration

90-degree V-8 w/five cross bolted nodular iron main bearing caps w/provisions for jet-spray oil cooling

Block Material

A319 sand-cast aluminum w/pressed-in iron liners

Crankshaft

Forged steel

Pistons

High-strength hypereutectic aluminum w/friction-reducing polymer skirt coating

Connecting Rods

Forged steel w/floating wrist pins

Cylinder Heads

Cast aluminum hot-V type w/ 36 mm intake valves, 29 mm sodium-filled exhaust valves

Valvetrain

Dual overhead camshafts; four valves per cylinder w/dual independent valve timing

Firing Order

1-5-4-3-6-8-7-2 (1-4-6-7 w/AFM)

Ignition System

Coil-on-plug

Turbocharging System

Two low-inertia twin-scroll turbochargers w/electrically controlled wastegates and water-to-air intercooling

Max Boost

20 psi (1.38 bar/138 kPa

 

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