Cadillac CT6 V-Sport 4.2L Twin Turbo V-8


General Motors’ new hand-built 4.2L twin-turbo V8 for the 2019 Cadillac CT6—which features “hot V” engine architecture, similar to engines built by BMW, Audi, and Mercedes—is the first Cadillac-exclusive engine produced in 26 years.

Two versions of the engine are planned: a 550-horsepower engine for the all-new CT6 V-Sport, and a 500-hp version for other CT6 models.

The engine will be built at GM’s Performance Build Center in Bowling Green, KY where the Chevrolet Corvette is built.

Automotive News referred to the new Cadillac engine as “the most technically complex and advanced regular production engine ever from GM.”

The 4.2L engine is a quad-cam, 32-valve, direct-injected aluminum power plant with the twin turbos and catalytic converters located between the banks of cylinders—the so-called “hot V” design favored by the top German automotive engineers.

2019 Cadillac CTS with new twin-turbo V8

(Image/General Motors)

“The arrangement saves space and enables the engine to be packaged in the CT6 without modifications to the car’s internal sheet metal. But the hot V also creates significant challenges in managing under-hood temperatures. Catalytic converters usually operate between 400 and 600 degrees (Fahrenheit) once a vehicle is warmed up,” the Automotive News report said.

With the turbos located so close to the intake ports on the cylinder heads, instant acceleration is available once the turbos have spooled.

Both versions of the ’19 CT6 are all-wheel-drive and will feature this new engine mated to a heavy-duty version of GM’s new 10-speed automatic transmission.

Cadillac officials say the engine has Active Fuel Management as well as a stop-start system. The engine is still being tuned, so no fuel economy figures were announced.

4.2L Twin-Turbo V8 Preliminary Engine Specs
Engine Block90-degree V with five cross-bolted main bearing caps; sand-cast aluminum with pressed-in iron cylinder liners
Bore/Stroke3.39 in. x 3.35 in./86 mm x 90.2 mm
CrankshaftForged steel
PistonsHigh-strength hypereutectic aluminum with friction-reducing polymer skirt coating
RodsForged steel with floating wrist pins
Compression Ratio9.8:1
TurbochargersTwo low-inertia twin scroll with electronically controlled wastegates and water-to-air intercooling