For the first time in 26 years, Cadillac will have an exclusive engine -- a 4.2-liter twin-turbo V-8. The new engine makes good on a 2016 promise by brand President Johan de Nysschen.
The limited-production engine -- hand-assembled and signed by the builder -- will be made in General Motors' Performance Build Center at the Chevrolet Corvette plant in Bowling Green, Ky.
The 2019 Cadillac CT6, arriving in the first half of next year, will be the first vehicle equipped with the new engine, Cadillac officials said. Two versions of the engine are planned: The CT6 V-Sport, a new model, gets the 550-hp engine, while a 500-hp version will be available in other CT6 models, such as the Platinum.
Perhaps the most technically complex and advanced regular production engine ever from GM, the 4.2-liter is a quad-cam, 32-valve, direct-injected aluminum motor. The two turbochargers and the catalytic converters are placed between the banks of cylinders. The design, known as the "hot V," is used by Cadillac's chief German rivals.
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 underhood temperatures. Catalytic converters usually operate at between 400 and 600 degrees once a vehicle is warmed up.
"During the design of [turbocharged] engines, we are always struggling about where are we going to put the turbos," said Jordan Lee, chief engineer for GM's V-8 engines. "You can put them on the sides of the engine or in the valley. For compactness and packaging reasons for it to be able to fit under the hood of the CT6, we went with the hot V architecture, similar to what you see on Audi, BMW and Mercedes."
Lee said his team looked at how German engineers managed heat in their hot V engines and used a variety of the same techniques while paying close attention to the management of air flowing over the engine and the coolant and oil circuits inside the block and heads. To help dissipate heat, Lee said, cooling fans can run and coolant might still circulate through a hot engine once it has been turned off.