Naza Italia has officially introduced the spider version of the SF90 Stradale, the SF90 Spider. Ferrari’s first retractable hard top hybrid was unveiled to Malaysians in a digital debut. This is the prancing horse’s latest and first open top Plug-In Hybrid Electric Vehicle (PHEV) featuring a V8 Twin-Turbo engine and 3 electric motors that is designed to pave way for the future of the brand in the coming decades.
The Powertrain
In a first for a Ferrari production spider, the SF90 Spider has plug-in hybrid architecture in which the internal combustion engine is integrated with two electric motors at the front, which comprise the RAC-e (Cornering Angle Regulator, Electric) system, and one at the rear derived from and named after a Prancing Horse Formula 1 innovation, the MGUK (Motor Generator Unit, Kinetic). The synergy between the internal combustion engine and the electric motors allow the car to unleash a maximum of 1,000hp and put the SF90 Spider not only at the very top of the Ferrari range of road cars, but also its category.
The SF90 Spider’s powertrain architecture features the V8 turbo ICE, an 8-speed DCT with E-diff, the RAC-e electric front axle with two independent electric motors that also provide all-electric propulsion, the MGUK electric motor located at the rear between the engine and the gearbox, the high voltage battery and electric motor control system (inverter).
The SF90 Spider sports the similar completely redesigned 8-speed, oil-bath, dual-clutch gearbox launched on the SF90 Stradale. An optimised layout, achieved through the adoption of a dry sump and a significantly more compact clutch assembly with a 20% smaller exterior diameter than the one in the 7-speed gearbox, has shaved 15 mm off the installed height in the car. This, in turn, lowers the centre of gravity of the running gear by the same amount.
The introduction of a "hot tube system", which transfers sound more directly to the cockpit, has produced fuller, richer harmonics across the entire frequency range, improving both in-car sound quality and intensity as rev rise compared to previous Ferrari V8s.
The power flow of the SF90 Spider’s hybrid system can be divided into two main areas:
- Power delivery, based on driver input via the accelerator pedal, processed by the engine control system and the hybrid control system, and constantly monitored by the electronic control systems. The power delivery modes can be divided up as follows:
- Electric mode, entrusted to front axle (FWD mode)
- Hybrid mode, entrusted to the ICE and the MGUK (RWD configuration)
- 4WD hybrid mode, with electric front axle available on-demand for traction requirements exiting corners and energy recovery in lift-off/ braking
- Energy recovery (battery charging), managed entirely by the hybrid system’s control logic using three strategies:
- Regenerative braking, available on both axles both under standard braking and when ABS is active
- Overbraking, active on both axles when accelerator pedal is lifted, managed independently on right and left front wheels
- ICE recharge: battery-charging function achieved by load point shifting between the ICE and the rear MGUK electric motor.
How the PHEV system works?
Under normal braking conditions, energy recovery using the electric motors is the priority: the hydraulic braking system intervenes to support the electric one in all sharp deceleration conditions. At high speeds and in high gears, the combined contribution of the electric motors in high grip conditions helps lower the ICE’s response times, thus significantly improving longitudinal acceleration and thus performance.
Because of the pivotal role hybrid system power management plays in the SF90 Spider driving experience, the traditional Manettino is now flanked by an additional steering wheel-mounted selector, dubbed the eManettino, which manages the power flows from and to the high voltage battery and the wheels (traction). It offers the driver a choice of four modes:
- eDrive: the internal combustion engine remains off and traction is entrusted entirely to the electric front axle. Starting with a fully charged battery (with a capacity of 7.9 kWh), the car can cover up to 25 km in this mode which is ideal for city-centre driving or any other situation in which the driver wishes to eliminate the sound of the Ferrari V8. The 135 km/h speed limit means the car can also be used on out-of-town roads;
- Hybrid: this setting optimises the system’s overall efficiency. The control logic autonomously decides whether to keep the internal combustion engine running or turn it off. Power flow from the electric motors is limited to conserve battery power;
- Performance: this mode keeps the ICE running because the priority is more on charging the battery than on efficiency. This guarantees that power is instantly and fully available when required. This mode is best suited to situations in which driving pleasure and fun behind the wheel are the main focus.
- Qualify: this mode allows the system to achieve maximum power output by letting the electric motors work at their maximum potential (162kW). The control logic prioritises maximum performance over battery charging.
