Cadillac is one of the very few automotive marques ever to built a production V-16 engine, which it did during the 1930s. With more than seven litres of displacement and 16 pounding pistons, the massive V-16 was an engine with the credentials and the mandate to shock and awe.
Today’s luxury buyers still love over-the-top powerplants but buyers in various global markets, especially China, need other engine offerings for the sake of fuel consumption sanity and to give them the option to stay under very significant tax thresholds. As a result, the 2.0-litre “four” and 3.0-litre V-6 have evolved as the go-to engine formats for any premium nameplate with global volume ambitions.
Such, therefore, will be the case for Cadillac’s new CT6 flagship sedan, soon to make it debut at this year’s New York Auto Show. When it lands in dealerships later this year, it will be available with Cadillac’s carryover 2.0-litre turbocharged “four” and two brand new V-6 engines – a new 3.6-litre that replaces the current 3.6-litre unit, and the “more premium” twin-turbo 3.0-litre V-6.
3.0L Twin Turbo with Cheese
At a press briefing held in Detroit’s historic Garden Theatre, powertrain engineer, Richard Bartlett, held forth on the new 3.0L V-6, heralding it as the only V-6 in the marketplace to currently combine twin turbochargers, direct injection, stop-start technology, and cylinder de-activation.
Initially at least, the 3.0L Twin Turbo will be exclusive to the CT-6, as its premium engine offering, and mated to the new 8L90 eight-speed automatic transmission.
Back in the 1930s, cylinder count and displacement may have defined luxury powerplants but these days, says Bartlett, it’s all about “power density” – how much power you squeeze out of a defined displacement. At 133-hp per litre, he calls the new 3.0L one of the most power-dense V-6 DOHC engines in the world.
The Audi 3.0L TFSI was clearly one of the competitive engines in the crosshairs of Cadillac’s new engine. Cadillac is claiming a successful strike, as its new engine is both more powerful and quieter than the Audi unit. Peak output is estimated at 400 hp at 5,500 rpm, with 400 lb-ft of torque available between 2,500 and 5,000 rpm.
Notable technologies include…
> Feather-light titanium-aluminide turbines, which ultimately create quicker “spooling” to further mitigate turbo lag;
> A top-mounted intercooler, based on the Corvette ZR1 design, which facilitates a shorter route for the pressurized and cooled air into a single throttle body, to ultimately create fast torque production;
> Many hardened and additional heavy-duty materials, to withstand the higher pressures and temperatures emanating from this power-dense unit.
Yes, this is an all-new 3.6L V-6
To make sure we understood how fundamentally new the 3.6L V-6 is, chief powertrain engineer, David Muscaro, handed us the only two parts carried over from the current 3.6L V-6 – a hydraulic lash adjuster, and the roller-followers for cylinders one, three, four and six.
They were obviously expecting some skepticism, because displacement has remained steady at 3.6 litres, but that’s only because there was some rounding going on; the current V-6 is actually 3,564 cc, and the new one is 3,649 cc.
This new V-6, rated at 335 hp and 284 lb-ft of torque, will be available initially on CT-6, CTS, and ATS. Those are all RWD or AWD applications, but Cadillac said this engine could easily go FWD.
Both the 3.0L Twin Turbo and this naturally aspirated 3.6L V-6 are part of a new engine family, which will also spawn new V-8s at some point.
They share many design elements, including the stop-start technology, and a cylinder de-activation system that shuts down only one cylinder on each bank (2 and 5), versus systems from other makers, which typically shut down all the cylinders on one bank of the V.
Other common and notable highlights include…
> Rigid aluminum block;
> A four-cam phasing system with a novel “intermediate park” position, which enables late inlet valve closings in certain situations;
> A cooling system that sends coolant to critical areas in a parallel strategy (versus typical systems, which send coolant through the engine in series, front to back);
> Cylinder heads with direct injection and integrated exhaust manifolds;
> Timing chain with specially shaped and cushioned sprockets for quiet operation;
> A two-stage oil pump, now moved inside the block, that also helps keep things quiet
Cadillac claims the 3.6 is quieter than the industry benchmark, the Infiniti 3.7-litre V-6.
Hey, what about the V-8s?
Muscaro re-assured us, and the Cadillac faithful, that the marque would continue to be available with V-8 power, though he pointed to their more limited role in the future, in the performance-above-all V-series Cadillac hot-rods.
Get used to it… luxury powerplants are moving from big displacement to big power density, in a range of sizes to fit the ever expanding and broadening definition of premium vehicles.