Alfa Romeo Giulia Quadrifoglio: a far cry from the original 510 hp, the V6 engine has finally been boosted to 600 hp

Tuner Scara73 has just unveiled its latest creation, and it starts with a big surprise. Put through its paces on the test bench before being tuned, this Alfa Romeo Giulia The 2020 Quadrifoglio turned out to be far from the 510 hp advertised by the manufacturer, topping out at just 489 hp. But after a complete engine overhaul and the installation of larger turbos, the shop turned things around spectacularly, boosting the Italian sedan to nearly 600 hp and 800 Nm of torque.

As a reminder, the Italian tuner Scara73, already known for having upgraded an Alfa Romeo 4C to 335 hp. This time, his latest project involves a Giulia Quadrifoglio that now boasts nearly 600 hp. In a video recently posted on his YouTube channel, the tuner offers a behind-the-scenes look at this transformation, carried out for a loyal customer, Francesco, a performance enthusiast who already owns several Alfa Romeos that have passed through Scara73’s hands.

A carefully selected Giulia Quadrifoglio

The base vehicle chosen is a May 2020 Alfa Romeo Giulia Quadrifoglio, a version particularly prized by connoisseurs since it lacks a gasoline particulate filter (OPF). According to Scara73, these are simply the models offering the best performance potential. The car already boasts an attractive configuration with its Rosso Competizione paint, exposed carbon fiber roof, carbon-ceramic brakes, and Sabelt carbon fiber bucket seats. But the goal wasn’t purely aesthetic. Above all, Francesco wanted a car with better performance while still being enjoyable to drive on a daily basis.

Extensive tuning of the twin-turbo V6

To achieve this goal, Scara73 undertook a project that went far beyond a simple engine remap. The V6 engine was removed so that work could be performed directly on the turbochargers. These were slightly enlarged to increase their airflow capacity without compromising low-end responsiveness, one of the Giulia Quadrifoglio’s key strengths.

The work also provided an opportunity to refurbish several components. All of the turbo oil lines were replaced, the cooling system was overhauled with a new water radiator, and various small leaks that had developed over the years were repaired. The transmission also underwent a complete fluid change, with replacement of the fluids and filters.

Once the engine was reinstalled, the tuning process continued with the installation of downpipes fitted with Euro 6-certified 200-cell sport catalytic converters. The owner wanted to keep the car equipped with a catalytic converter, but that didn’t stop the tuner from pursuing high performance. The exhaust system was also replaced with a complete titanium setup featuring pneumatic valves controlled independently of the driving modes. This solution allows for a certain level of discretion during daily commutes while unleashing the full sound of the V6 when the valves are open.

From 489 hp to nearly 600 hp

Before any modifications were made, the Giulia Quadrifoglio was put through its paces on the dyno. Surprisingly, it produced only 489 hp and 604 Nm of torque—about 20 horsepower less than the official rating. After installing the new parts and making numerous electronic adjustments, the final result is impressive. Scara73 reports having created no fewer than 14 different maps and spent two and a half days of bench testing to optimize the system.

The verdict is clear: 594 hp and nearly 800 Nm of torque. More specifically, the tuner claims up to 780 Nm at the rear wheels. According to him, it is very difficult to exceed 550 to 560 hp with the stock turbochargers on this engine. The modifications thus added about 40 to 50 extra horsepower while maintaining a power delivery very similar to that of a standard Giulia Quadrifoglio at low RPMs.

One of the most interesting aspects of this tuning is precisely how it preserves the engine’s character. The graphs shown in the video demonstrate that the difference in response at low RPM is virtually imperceptible. Starting at 2,700 rpm, the tuned version matches the original power curve before surging well above it across the rest of the operating range, with a difference of nearly 100 hp at times.

A cavalry force that is difficult to utilize

The test drive conducted by Scara73 quickly reveals the limitations of rear-wheel drive. Even with tires that offer excellent grip and on a hot day, the tuner explains that the car still struggles to transfer all its power to the road up through fourth gear.

To complement this new setup, the redline has been raised to 7,500 rpm, allowing the twin-turbo V6 to keep revving higher for longer. The car’s response during acceleration speaks for itself. Between the constant intervention of the traction control system and the difficulty of containing nearly 800 Nm of torque on the rear axle, this Giulia Quadrifoglio seems to have entered a whole new dimension.

Another demonstration of the Alfa Romeo V6's potential

This build once again demonstrates the significant potential of the 2.9-liter V6 engine developed by Alfa Romeo. Already renowned for its performance in its stock configuration, it is capable of producing nearly 600 hp while remaining practical for everyday use when modifications are carried out with care. As a reminder, the Maserati 3.0L V6 Nettuno engine is an evolution of the Alfa Romeo 2.0L V6 engine. This Nettuno delivers 630 hp in the supercar Maserati MCPura, and 740 hp on the Maserati MCXtrema… without hybridization!