The First Road-Legal XX Car

Ferrari’s Special Version cars push the performance of its production models to new extremes. Some, such as the 488 Pista and 812 Competizione, have earned a rightful place in the Prancing Horse’s recent pantheon. Ferrari’s ‘XX Programme’, on the other hand, offers a select group of expert client drivers extreme cars that are not homologated for the road, to drive on the very limit on the track. One such model is the FXX-K EVO.

Ferrari has now drawn on these two different spheres of experience to create a Special Version that draws on the programme’s concepts to make it effectively a road-legal XX: the SF90 XX Stradale. Its performance has been raised to impressive new heights by an additional 30 cv, specific software logics and the use of radical new aero solutions, not least a fixed rear wing, the first to appear on a road-going Ferrari since the days of the F50.

Aerodynamic

PEERLESS PERFORMANCE

The SF90 XX Stradale delivers the most efficient aerodynamic performance of any Ferrari road car, making it comparable only to that of the LaFerrari supercar. It delivers double the maximum downforce of the SF90 Stradale, improving grip and yielding a palpably faster lap time at Fiorano. The product of Maranello’s inestimable racing experience, this result was achieved by redesigning the cooling flow management for the thermal and electric components as well the engine compartment.

AN AUTHENTIC ‘XX’ CAR WING

The SF90 XX Stradale’s signature element is most definitely the rear fixed wing, which was thoroughly researched, tested, and developed on the track-ready XXs. This is an element with enormous aero potential and has been perfectly integrated into the car’s volumes, thanks to close collaboration with the Ferrari Styling Centre. Its shape was dictated by the need to efficiently hone the way in which the pressure field created by the wing interacts with the complex pressure and backpressure systems that develop around the shut-off Gurney.

The latter also redesigned, has two configurations: LD (Low Drag) in which the mobile element is raised, minimizing drag, while in HD (High Downforce), the mobile element is lowered, uncovering the fixed area. This generates an overpressure area, which deflects the incoming flow vertically to deliver the absolute maximum downforce possible: 530 kg at 250 km/h.

PowerTrain

The SF90 XX Stradale has inherited the SF9O Stradale’s signature PHEV layout, in which the V8 internal combustion engine is integrated with three electric motors, two independent on the front axle and one located between the engine and gearbox at the rear. This configuration allows the car to unleash a maximum of 1030 cv (+30 cv more than the SF90 Stradale), setting a whole new Ferrari performance benchmark.

PERFECTION IS IN THE DETAILS

Thanks to its massive 797 cv, the mid-rear-mounted V8 turbo raises the performance limit bar still further for this particular architecture. The SF90 Stradale’s power unit has been developed to be more extreme, thanks to an increased average compression ratio, achieved through polishing the inlet and exhaust tracts as well as specific machining of the combustion chamber and pistons. The removal of the secondary air system also slashed 3.5 kg off the engine’s weight.

THE SOUND OF THE TRACK

The redesign of the SF90 XX Stradale’s soundtrack also brings its racing soul to the fore: to produce an even fuller, richer sound and celebrate the harmonics right across the V8’s rev range, the hot tube system was optimised. This transmits the combustion pulsations into the cabin, highlighting the high-frequency treble to reveal the ultimate evolution of the Ferrari V8 at its most magnificent.

NEW GEAR-SHIFT LOGIC

The 8-speed dual-clutch gearbox that made its first appearance on the SF90 Stradale, also reappears on the SF90 XX Stradale. However, the gear-shift logic hase changed significantly: the car uses the logic introduced on the Ferrari Daytona SP3 to enhance gear-shifting sound and the resulting driving thrills, by introducing a noise similar to the tell-tale pop from the exhaust that happens on lift-off at medium/high revs in high performance driving. To that end, a specific new engine calibration was developed that works in synergy with the gearbox control logic.

DESIGN

A MOVING SCULPTURE

Styling-wise, the SF90 XX Stradale incorporates the engineering principles that underpinned the SF90 Stradale and pushes them to new levels. In terms of its concept, this is to all intents and purposes an XX car: its characteristics, the fruit of a more incisive, radical language, are thus even more extreme still. The SF90 XX Stradale’s styling cues are designed to highlight its thoroughbred performance characteristics whilst still retaining the pure lines and forms of its predecessor.

SPREADING ITS WINGS

There is no doubt that one of the most distinctive characteristics of the SF90 XX Stradale’s design is its rear wing. The tail volume, which has been specifically redesigned with aero in mind, is now sleeker, giving it the long tail silhouette typical of racing cars. The air intakes for the intercoolers are now larger too, channelling the air towards the radiators more efficiently.

TENSION AND DYNAMISM

The arrow-shape front wing concept has been retained on the SF90 XX Stradale; the headlights are now integrated into this area by two vertical wing profiles. This creates a more geometric language that reflects the spirit of this new car. Another distinctive element is the two imposing wing profiles dominating the air intakes, which look as if they are floating, thus making the car seem broader and more glued to the asphalt than ever.

INTERIOR

The guiding principle in the design of the SF90 XX Stradale’s interior was to highlight the cockpit’s racing vocation through targeted actions that would make significant weight-savings. The main areas involved were the door panels, tunnel and mats, which are now simpler in terms of their shape and the materials used thanks to an emphasis on technical fabrics, while carbon-fibre was used for functional areas.

SPECIFIC RACING SEAT

A specific racing seat with a clearly visible carbon-fibre tubular and foam structure was designed especially for the SF90 XX Stradale to enhance sporty driving pleasure without compromising on comfort. The backrest rotation mechanism has been integrated into the seat using elastic trim materials which disguise its action. This means that the structure looks seamless at all times – just like a single-piece seat - while also allowing the backrest to be adjusted. This feature saved 1.3 kg in weight compared to the SF90 Stradale’s single-piece seat.

VEHICLE DYNAMICS

UNPARALLELED EXHILARATION

The focus with the SF90 XX Stradale’s development was to produce the most high-performance Ferrari road car ever that also delivered superb fun behind the wheel, as well as fully retaining all of the functionalities of the SF90 Stradale’s hybrid powertrain. Also of major importance was usability of performance, particularly the electric mode’s ability to deliver surprisingly high performance driving both in urban settings and all the way up to out-of-town trips – the top speed in eDrive mode is 135 km/h.

ABS ‘EVO’

Another major new addition is the ABS EVO controller, which debuted on the 296 GTB and, thanks to its integration with the ESC sensor, improves both performance and repeatability in high performance braking in the dry. The system maximises the repeatability of the braking manoeuvre to a target value, reducing losses due to the tolerances of the components or the natural variability of test conditions. As a result, the controller allows the SF90 XX Stradale to brake later and in a more repeatable manner, thus enhancing its handling on the track.

EXTRA BOOST

Also debuting on SF90 XX Stradale is the extra boost control logic which guarantees a performance surplus for a limited time window. The objective of this software, which is only active in Qualifying mode of the eManettino, is to reduce lap time by increasing the limit of the deliverable power coming out of a bend. This short power boost of around 2 seconds guarantees a reduction of lap time of 0.25s at Fiorano.

Source: Ferrari