Lately, it seems as if all the rage in supercars is a high-strung V6 engine with a couple of hairdryers hanging off the side. This year we’ve brought you looks at the Aston Martin 3.0-liter TM01 twin-turbo V6, the Acura NSX’s 3.5-liter twin-turbo V6, and now there’s another all-new twin-turbo V6 supercar engine coming to life, this time with a trident on the engine cover.
While a V6 engine to power a supercar really isn’t all that surprising these days, the real point of pride for the automaker is that this engine is 100-percent Maserati, and 100-percent built in Modena, Italy. Designed by the Maserati in-house high-performance propulsion team, the all-new Nettuno 3.0-liter V6 powerplant incorporates a host of new technology.
The Basic Layout
The basic architecture of the Nettuno engine is that of a tried and true 90-degree V6 engine block, with an over-square rotating assembly, measuring 88mm (3.464-inch) bore diameter, and 82mm (3.228-inch) stroke for 2,992cc of actual displacement, and what is fast becoming normal for twin-turbocharged V6 engines, 11.0:1 compression ratio.
The dual overhead cam cylinder heads feature four-valves-per-cylinder, with what appears to be a fairly standard hydraulic follower valvetrain. The engine features variable valve timing in the form of cam phasers on both the intake and exhaust camshafts. However, where this engine gets really interesting is if you were to flip the heads over and look at the combustion chambers.
The Crown Jewel: Pre-Chamber Ignition
There, you will find a unique dual combustion chamber setup, consisting of a small chamber right at the tip of the main spark plug, which then connects to the traditional combustion chamber where the spark plug electrode would normally protrude. In the “pre-chamber”, the spark plug ignites a specifically metered portion of compressed the air-fuel charge and creates directed jets of combustion which ignite the main air-fuel charge in the cylinder.
The project to make the pre-chamber combustion process feasible in a road car began in 2015. Linked to the pre-chamber ignition technology developed for Formula 1 engines, a small team of engineers developed a prototype, and after the first dyno, it was realized that the technology was a success.
The idea behind the pre-chamber being, that the directed initial combustion leads to a much faster flame propagation in the cylinder, along with a more complete burn of the air-fuel charge. The technology has been tried previously and there were a number of issues that made it unsuitable for a road car — namely instability at low engine loads and noise levels that impaired the vehicle’s NVH performance. However, the team at Viale Ciro Menotti developed both hardware and software solutions to solve those issues.
Solving Problems With Twins
One of the solutions to the issues is the incorporation of a second spark plug at the corner of the traditional combustion chamber, which Maserati refers to as the “lateral sparkplug.” This ignition source acts as a supplemental ignition source when the engine isn’t operating in an area of the map which requires the pre-chamber ignition system to function.
In addition to the “twin spark” arrangement, the Nettuno engine also features what Maserati is calling a “Twin Injection System, which is essentially both direct and port fuel injection. Both sets of injectors run off the 350-bar (5,076psi) high-pressure fuel supply and the injection strategy is altered based on engine load and driving conditions, much like the pre-chamber ignition.
The twin turbochargers’ specifications are scarce, but an interesting tidbit that has been released is that they will be controlled by a pair of electric wastegates. Also in the “sci-fi” category is a continuously variable dry-sump oiling system. Using a traditional shallow pan and external reservoir, the pump itself is fully-variable by the ECU.
With an 8,000-rpm rev-limit, the Nettuno engine produces 621 horsepower at 7,500rpm and 538 lb-ft of torque at 5,500 rpm. Not bad at all for Maserati’s first “Made in Modena” engine. Maserati is quite serious about its efforts to produce top-tier engines in house, as the famous Viale Ciro Menotti plant had to undergo extensive renovation to become a new engine development hub.
The Nettuno will debut in September in the engine bay of the firm’s MC20 “Super Sportscar” and if it performs as the engineers expect, we’d be willing to bet we’ll see more new high-performance engine designs coming out of Modena.