The Maserati MC20’s new Nettuno V6 is a high-tech showpiece

Posted on

It has been more than twenty years since Maserati developed an in-house 90-degree V6 engine, the last of which has its genealogy going back 30 years. That story started in 1968, when Citroën took a majority stake in Maserati, and the French asked the Italians to make an engine for the 1970 Citroën SM. The famous Maserati engineer Giulio Alfieri designed a 2.7-liter V6 that Produced 170 horsepower which could be built with Maserati’s existing V8 tools, hence the 90 degree angle. Alfieri then revised that V6 and bored it to three liters, increasing power to 187 horsepower, for use in the 1972 Maserati Merak.

A decade later, Maserati – now owned by Alejandro de Tomaso, who had fired Alfieri – embarked on Alfieri’s V6 philosophy when developing a grinder for a new sports car. The resulting 2.0, 2.5 and 2.8 liter displacement V6 engine was the first twin turbocharged engine to be installed in a production car. That car? The hot, beautiful mess known as the 1984 Maserati BiTurbo.

Nearly 10 years later, the 1992 Maserati Ghibli II would get a 2.0-liter version of this 90-degree V6 with 306 horsepower. The 1995 Ghibli Cup boosted that mill to 330 horsepower, crowning the 2.0-liter V6 as the most powerful engine in a production car, echoing ’90s icons like the Jaguar XJ220 and the original Bugatti EB110 (both per liter).

When the Ghibli left production in 1998, Maserati turned over engine development orders to Ferrari on behalf of Fiat, which owned both car manufacturers.

Nettuno, the new beating heart of Maserati

Now we have the Nettuno, a 90-degree 3.0-liter V6 built to power Maserati’s renaissance, making its debut in the sturdy, aerodynamic shape known as the MC20. With 630 hp and 538 lb-ft of torque, the engine picks up almost where the Ghibli Cup left off: at 210 hp / liter, the Nettuno is one of the most powerful in the world. The Bugatti Chiron, Ford GT and McLaren 756LT do not creak 200 hp / l. The only production cars on base are Euro specials such as the Mercedes-AMG A45 (208.4 hp / l). Behind them are seven-digit hypercars such as the SSC Tuatara (229 hp / l) and Koenigsegg Jesko (256 hp / l on gas, 320 hp / l on E85).

The word we are looking for in Italian is bentornato. Welcome back, Maserati.

The automaker recently organized a virtual tour of its Engine Lab in Modena to show off the work that went into the intricate internal parts and assembly of the Nettuno, and our first question concerned the origins of the Nettuno. We’ve previously written about reports that the Nettuno is derived from the Ferrari F154 V8 that Maserati uses in Ghibli, Quattroporte and Levante’s top trims. Alfa Romeo turned the F154 into the six-cylinder 690T engine for its Giulia and Stelvio Quadrifoglio trims. Bozi Tatarevic examined the Nettuno and scanned everything from part numbers to cooling jackets to determine that while the Nettuno’s heads are unique, fundamental elements of the block’s design and many additional parts resemble Ferrari and Alfa Romeo antecedents. .

What’s more, the Nettuno is designed as two three-cylinder engines that operate on a common crank with four main journals and three rod journals each containing two pistons. Like an even-burning engine, the crank experiences a fire event every 120 degrees. These principles could all have been drawn from the Alfa Romeo 690T.

We asked Maserati chief engineer Matteo Valentini about the F154 connection. He replied, “Of course there are solutions you can find on other bikes, but don’t be fooled by the exterior shape of the bike.” He admitted that Maserati’s engineers were leveraging the knowledge across Fiat-Chrysler – the same resources we share at other OEM conglomerates such as General Motors and the Volkswagen Group. Still, Valentini emphasized the in-house, start-to-finish development of the new V6, saying that the engine “was designed by us, developed by us, manufactured by us, and assembled by us.”

The Nettuno shares its architecture with Alfa Romeo’s 690T but is cast by a different supplier, and the block “has a different content inside, it has a different bore, [and] it has several oil channels. According to him, the heart of Maserati to move forward is “a brand new project that uses all the experience we had in the past”.

The combustion in the front chamber provides a boost of 100 hp

The killer app of the twin-turbo V6 is unequivocally not shared with the Ferrari and Alfa engines: pre-chamber combustion, an ignition technology that German supplier Mahle started working on in 2010. Mercedes-AMG Petronas F1 adopted it in 2014 and Mahle supplied it for Ferrari Formula 1 cars in 2015. The technology has served large bore stationary gas engines for decades, and Honda added a variant of this technology to its CVCC more than 40 years ago. motor applied.

Under certain conditions, a pre-chamber on top of the combustion chamber shoots targeted flames into the cylinder during ignition. This ensures a more complete combustion and reduces emissions. However, a cost-effective solution for modern automotive engines was needed to address shortcomings, including unwanted NVH, substandard efficiency at low engine loads and strict emission regulations.

Pre-chamber ignition, which comes in active and passive form, generally uses one spark plug. Maserati’s passive method fills in the front chamber’s weaknesses by using two. A plug is in the front chamber of 1.5 cc. A second plug inserts its electrode into the side of each square chamber. This makes the Nettuno a twin-spark engine with double injection; port-injection works on a 6 bar fuel rail, direct injection on a 350 bar fuel rail. Maserati’s patent application for the technology says it enables a 15% higher compression ratio and fuel savings of up to 30%. (Before anyone accused Maserati of stealing Alfa Romeo’s twin-spark cleverness, Maserati made twin-spark engines for the inline-six in the 250 F race car as early as the 1950s, and later for road cars like the Mistral too. was used dual overhead camshafts, fuel injection and semi-circular combustion chambers.)

Maserati’s press releases have explained the second plug “[ensures] constant combustion when the engine is running at a level that the pre-chamber does not need to start. “We asked Valentini about the performance parameters that trigger the pre-chamber ignition, he told us the system is not binary, the pre-chamber ignition always contributes.

“At medium and low loads,” he said, “the standard injection is predominant. When you go from medium to high loads, the front chamber takes the advantage, and we … play with the spark drift to give the right priority to one. theirs.”

We asked how much power the pre-chamber ignition adds, he said just over 100 horsepower. The Nettuno goes from about 510 hp on standard injection to 620 or 630 with pre-chamber assistance.

Speaking of power contributions, the Nettuno’s turbos have so far been programmed to wind up to 3 bar (43.5 psi) and have electronically controlled wastegates. As for why the turbos hang to the side instead of sitting between the cylinders, Valentini said the team looked at a hot-cattle setup but couldn’t find a simple, reliable solution that could hit the 210 hp / liter target . The traditional setup is cleaner and provides a lower center of gravity.

The dottori will now build you

Maserati has not only given the Nettuno a supercar at home, the engine also gets supercar production techniques. There are about 1,300 parts in total, divided into about 100 sub-assemblies and pieces. In a cleanroom at the Engine Lab in the automaker’s historic Viale Ciro Menotti facility, a small number of technicians – Maserati calls them dottori (“doctors”) – turn those 100 components into a Nettuno in six stages. Each stage requires three to four hours, so it can take three full business days for one engine to be completed. Powertrain facility manager Jonata Azzali told us that the time it took is in part why Maserati thought it better to distribute the process to technicians instead of having one person build one complete engine.

But let’s face it, while Maserati is praised for handcrafted luxury, the brand hasn’t always done well with handcrafted technology. On the Nettuno, the automaker is much more focused on eliminating points of failure than celebrating individual craftsmen. Azzali’s tour of the build space was basically a tour of the numerous digital safeguards that Maserati has implemented for quality control.

The HVAC system maintains positive pressure in the build space to expel stray particles. Two screens at each construction station show what needs to be done and how it should be done. Cameras placed on the ceiling, on fixed equipment and on tools monitor items such as the correct placement of the seals on the cylinder liners and pistons. Electronic wrenches and screwdrivers control and record the torque applied to screws and bolts on each Nettuno. For the exhaust manifold, the screwdriver’s digital sensors are supported by a camera that ensures that the screws are placed in the correct order. When mounting main and rod bearings to the crank, barcode sensors control a set of trays that only allow the technician access to the correct bearing for the next step in the procedure.

Towards the end of the build, a 21-point helium test checks for leaks in the injection and fuel systems. This follows leak checks performed during assembly, such as those done just after the valves are installed. Finally, each Nettuno is sent to a test bench for 40 minutes to verify its power and torque. And once a month, Maserati chooses a random engine for a four-hour test bench.

The current line-up produces four to six engines a day, up to a maximum of 10. Unsurprisingly, the Nettuno was prepared to hold its own on racetracks around the world – and designed without a balance shaft – the Maserati engineers voted. his personality “underline the racing soul of the bike.” NVH calibration was inactive, while stints at full power give a ‘racing feel’.

And despite the extensive technical considerations, this is ultimately all about feeling. A brand that has been preaching Italian character and passion for nearly 90 years will not be served with soul-less mechanical excellence. The answer to the question of whether the Nettuno has such anima awaits our first ride with the MC20.