New Powertrains Underpin Cadillac Product Assault

Newly developed 8L45 8-speed transmission.

Other key elements of the twin-turbo engine and shared with the redesigned 3.6L V-6 include an aluminum block, a forged-steel crankshaft, polymer-coated pistons and high-copper-content, sinter-forged connecting rods.

A newly designed, 4-cam phasing system with intermediate park technology allows late inlet valve closing in certain conditions, which improves efficiency, and a newly designed cooling system targets specific “hot areas” of the engine. The engines also warm up faster, another efficiency enhancement.

The engines employ direct injection from Hitachi and thousands of hours of computational analysis were used to optimize the combustion process.

A simpler timing drive system with cushioned chain sprockets lends quietness to the engine, and the oiling systems move the pumps inside the block for quieter operation. A 2-stage oil pump further enhances efficiency of the mills.

Both engines leverage the same basic architecture, although the twin-turbo unit adds a number of components to support the forced induction and its 86-mm bore specification measures about 10% smaller than the 3.6L. The engines share an 85.8-mm stroke.

The engines will be built at GM’s Romulus, MI, engine plant, which recently received a $540 million upgrade for the work.

The twin-turbo will mate to GM’s 8L90 8-speed automatic transmission used on the Chevy Corvette Stingray and the automaker’s trucks and SUVs, while the 3.6L V-6 receives an all-new 8L45 8-speed gearbox specially developed for the CT6.

The investment in Cadillac will result in eight new products by 2020 and put it in five segments in which it currently does not compete. It also accelerates a turnaround mounted for the brand more than a decade ago that was slowed by GM’s financial crisis and, more recently, a repositioning in the market.

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