Car Tech

A Sneak Peek at Cadillac’s New 4.2L Twin-Turbo V8 from the 2019 CT6 V-Sport

While Cadillac knows its future bread and butter will come from SUVs and crossovers, the historic marque is also well aware that its legend was built on fast, luxurious, and exclusive sedans, tracing back to the V8, V12, and V16 cars of the ’30s and ’40s. And gosh knows, every premium brand needs a halo car.

The lads at Cadillac are about to take another swipe at the German performance sedan establishment with the 2019 CT6 V-Sport. Arriving in the first half of 2019, the key to this fresh assault is an all-new Caddy-exclusive 4.2L twin-turbo V8.

This clean-sheet design is Caddy’s first twin-turbo DOHC V8, and like turbo V8s found in the overseas target vehicles (Audi 4.0L, Mercedes-Benz 4.0L, BMW 4.4L), this one uses the “Hot-V” architecture that stuffs the turbos and catalytic converters within the engine’s V, with the intake ports fitted to the outside of the heads. Benefits of this design are compact packaging along with reduced turbo lag and emissions.

Power and torque outputs for this pressurized 90-degree 4.2L V8 have not been completely finalized, but at this point in development the engine makes 550 horsepower at 5,700 rpm, and 627 lb-ft of torque from 3,200 to 4,000 rpm, with 90 percent of that twist on board at 2,000 rpm. There will also be a non-V-Sport version generating a more modest 500 hp and 553 lb-ft.

So let’s look at the European competition’s engines in their highest state of tune. The Audi 4.0L V8 in the RS 7 makes 605 hp/553 lb-ft, the Mercedes-AMG 4.0L V8 in the GT R makes 577 hp/516 lb-ft, and BMW’s 4.4L V8 kicks out 600 hp/553 lb-ft in the new M5. Clearly, Cadillac is stressing torque over power here, and as chief engineer for Cadillac V8 engines Jordan Lee says, “We want that low end of the torque range and mid-range to be as fat as possible to give the driver the most responsiveness we can deliver. We do expect the bottom of that torque curve to come up with further development.”

This V8 is only being built for AWD applications, which – considering its rather healthy torque output – is probably a prudent engineering choice. It has variable valve timing on both intake and exhaust, and a gets AFM (automatic fuel management) that will have it running as a V4 under light loads. The twin-scroll turbo impellers are made of lightweight titanium-aluminide, spin to 170,000 rpm and huff 20 psi of air/fuel mixture into the cylinders, where it is squished by a 9.8:1 compression ratio.

This all-aluminum 4.2L bent-eight will be hand-assembled in GM’s Performance Build Centre in Bowling Green, Kentucky, and taking a page from the AMG playbook, each engine will be built by a single technician, and topped with a plaque bearing his signature.

The other part of the CT6 V-Sport’s powertrain equation is the Hydra-Matic 10-speed that replaces Cadillac’s current eight-speed unit. This is the first application of a higher-torque version of this transmission found in some other GM products. With a higher ratio spread (7.39) this brainy gearbox is no bigger or heavier. Ten gears is a lot, and some might question the need.

Assistant Chief Engineer for the transmission Mark Kieliszewski explains: “I’ll tell you what. You’re going drive this 10-speed and have no idea of how many gears it has. You’re going to be in the right gear at the right time, to be able to deliver this power to the ground in the most efficient and performance-minded way you want to.” And of course, there are paddle shifters if you think you can do it better.”

Having experienced this impressive 10-speed in the Camaro ZL1, we can say it works seamlessly and has the ability to stay one step ahead of your intentions.

By all accounts, the 2019 Cadillac CT6 V-Sport will be a formidable performance sedan that, as we’ve seen with other recent high-powered cars from Caddy, can put up numbers to rival or beat the best from Germany. The real challenge for Cadillac will be to pull buyers away from those Euro brands, a goal that has so far been elusive.