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05 gennaio 2021

Ben Pulman

A decade ago, Ferrari introduced a four-seater that utterly changed the concept of the GT sports car: the FF

An acronym for Ferrari Four, not only did the FF feature four sumptuous seats that cocooned the driver and their fellow occupants, but it was the first four-wheel drive Ferrari.

The combination of high-performance, incredible versatility, superb comfort and sophisticated elegance delighted clients. The FF was quite simply the most versatile car ever produced by Ferrari. But it was how Maranello created this unique blend that is more profound. The reason: an extraordinary Ferrari-patented four-wheel drive system, known as 4RM.

Unlike a conventional four-wheel drive fitted to a front-engined car, 4RM allowed for the retention of the mid-front engine architecture. With the V12 positioned behind the front wheels for optimal weight distribution, the ingenious but simple solution was to place a compact Power Transfer Unit (PTU) ahead of the engine. Located over the front axle, the new PTU managed torque to the front wheels and distributed it left and right as required.

The innovative layout meant a 50% saving in weight compared to a traditional four-wheel drive system, benefiting the power-to-weight ratio. A low centre of gravity was maintained, as was Ferrari’s ideal weight distribution, with more than 50% of weight over the rear axle despite it being a front-engined car.

The technical advancements didn’t stop there. The new 660cv engine was the first Ferrari V12 combined with an F1 dual-clutch gearbox, with the E-Diff incorporated into the gearbox casing to reduce weight. The sophisticated 4RM control electronics integrated with the E-Diff and F1-Trac traction control to guarantee superb control in all conditions. For the driver, the only consideration was which of the five Manettino positions to select, including a new Ice-Snow setting calibrated for maximum stability in low-grip conditions.

This was not Ferrari’s first four-wheel drive system, however. In the late 1980s, a special project was established – and two concept vehicles built, designated 408/4RM – to explore the potential of a host of innovations for future production Ferraris.

Constructed between 1987 and 1989, both vehicles used a unique 4.0-litre V8 – and one offered a glimpse of the future with an aluminium body structure. Exploiting Ferrari’s advanced foundry capabilities, the two cars were created with magnesium front bulkheads. Body panels were formed in lightweight composite, and hydraulic suspension allowed the ride height to be controlled.

The experimental hydraulic four-wheel drive also showed promise, with the technology granted a patent. Just as the FF’s PTU was compact, so too was the small-diameter coupling in the 408/4RM. This introduced sophisticated limited-slip control, endowing the concept cars with the responsive handling expected of a Ferrari.

Following a thorough evaluation of the projects, in 1991 Vice Chairman Piero Ferrari declared that four-wheel drive wasn’t yet suited to the company’s philosophy as ‘it increases car weight by some 200kg. In the future, however, we want our cars to be even lighter than today’s.’

That was Ferrari’s position for nearly two decades, as learnings from the 408/4RM and subsequent Millechili (or 1000 kilogrammes) concept reduced the weight of every generation of Ferrari road car with technologies such as aluminium body structures and panels. It was only with the advent of the FF, introduced in January 2011, that Ferrari revealed an innovative four-wheel drive system which satisfied its lightweight philosophy.

The technology was advanced still further with the introduction of the Ferrari GTC4Lusso in 2016. At the heart of the enhanced 4RM Evo system remained the innovative PTU, more precise than ever and able to deliver 90% of the available torque to the outside wheel.

In the GTC4Lusso, 4RM Evo was united with rear-wheel steering for the first time, creating the Ferrari-patented 4RM-S (four-wheel drive and steering) system. Rear-wheel steering made the car more nimble going into corners, and these sophisticated vehicle controls seamlessly integrated to enable the driver to effortlessly handle the GTC4Lusso’s extraordinary torque even on snow-covered, wet or low-grip roads.

A decade on the Ferrari 4RM system remains unique, and the FF and GTC4Lusso no less so.