Cadillac's first twin-turbo V8 detailed

Meet Cadillac’s first twin-turbo V8. It’s bad news for GM haters, too, for this new high performance bent-eight is packed with all the technology under the sun.

In a break from tradition, this new V8 features dual overhead camshafts, four valves per cylinder and two turbochargers, as well as stop-start and cylinder deactivation for improved efficiency.

It’s smaller, too, both in capacity at ‘just’ 4.2 litres and also in size thanks to the turbos being mounted in the vee, following the lead of Audi, AMG and BMW. One thing that isn’t small, however, is the grunt it produces, developing 373kW/750Nm in its lesser tune, which swells to an impressive 410kW/850Nm in its ultimate guise.

It’s the new flagship engine for Cadillac’s flagship car, the S-Class-sized CT6, the higher-powered tune propelling the sporty V-Sport variant.

Power is sent to all four wheels via a new 10-speed automatic, which carries a different code to that found in the brand new Camaro. Christened the Hydramatic 10L90, the new automatic offers a gear for every occasion, everything from a 4.696:1 first all the way to 0:636:1 10th for quick acceleration and highway cruising economy.

The engine is exclusive to Cadillac – for now, at least – but we wouldn’t bet against it spreading throughout the GM world in years to come.

Dare we speculate that the compact dimensions and power potential of this new V8 – which, annoyingly, doesn’t yet have an engine code – would make it an ideal candidate for the forthcoming mid-engined C8 Corvette? A car that might very well reach Australian showrooms.

In the meantime, here’s an in-depth look at what makes this new GM powerhouse tick.

Sixteen Caddy Facts

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1 - An 86mm bore and 90.2mm stroke results in a cubic capacity of 4192cc. Its undersquare layout reduces the size of the pistons, aiding engine response.

2 - Two tunes are available: the regular CT6 develops 373kW from 5000-5200rpm and 750Nm from 2600-4600rpm while the more powerful CT6 V-Sport makes 410kW at 5700rpm and 850Nm from 3200-4000rpm.

3 - The turbochargers are mounted in the vee of the engine, shortening the inlet tract to reduce spool time and improve packaging.

4 - Each turbocharger is a twin-scroll unit with an electronically-controlled wastegate and is integrated into the exhaust manifold.

5 - Firing order is 1-5-4-3-6-8-7-2, or 1-4-6-7 with cylinder deactivation engaged.

6 - Crankshaft is forged steel, as are the conrods. Block is sand-cast aluminium with four oil jets to cool the pistons.

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7 - In order to improve efficiency, the engine features cylinder deactivation and stop-start, but uses an auxiliary battery to operate power accessories when the engine is stopped.

8 - Direct fuel injection allows a high 9.8:1 compression ratio to be used due to the cooling effect of the fuel vaporising in the combustion chamber.

9- Water-to-air intercoolers lower intake temperature by more than 75˚C increasing air density.

10 - Unlike almost every GM V8 ever made the new 4.2 uses dual overhead camshafts with four valves per cylinder.

11 - Electronic wastegates allow precise boost control to a maximum of 1.38bar (20psi).

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12 - Power is sent through a 10-speed automatic. The three tallest gears are overdriven allowing for a theoretical 400km/h top speed, were it not for wind resistance!

13 - Each cylinder bank has its own fuel pump, which supplies fuel at 350bar (5075psi).

14 - Cadillac’s new engine will be built at GM’s Performance Build Centre in Bowling Green, Kentucky.

15 - Sodium-filled valves help dissipate heat. Intake valves are 36mm and exhaust valves 29mm.

16 - Pistons are hypereutectic (pressure cast with a higher silicon content to lessen thermal expansion) and coated with polymer to reduce friction.