1994 Ferrari F355 GTS

For the F355, Ferrari developed a new 3.5 liter 90° V8 engine developing 375bhp at 8250 rpm with a redline of 8500 rpm. The maximum torque was 268 lbs-ft at 6000 rpm. The specific output of this remarkable 5-valve unit was 109bhp per liter.

The engine's aluminum block had Nikasil-coated wet steel liners. Peculiarly light forged aluminum-alloy pistons drove the crankshaft through titanium alloy con rods previously seen only in Formula 1 engines. The engine's greatest innovation is its five-valves per cylinder, three intake and two exhaust, that combined high revs with high intake permeability maximizing gross efficiency. The aluminum head was ultra-high-strength with variable rigidity dual valve springs. The radial intake valves made conical cam profiles necessary and the high rotation speed necessitated a high lift for both reliability and long-term performance. The control lobe for the central intake valve was slightly offset, reducing pulse stress and the emission of un-burned hydrocarbons. The valves were actuated by hydraulic tappets with automatic play take-up, a first for engines that rev over 8000rpm. In accordance with racing design, Ferrari engineers created an extremely compact high-swirl combustion chamber of 11:1 compression ratio. The engine was controlled by a Bosch Motronic M2.7 twin hot wire electronic injection-static ignition system, and lubricated by a dry-sump engine oil circuit.

The exhaust system was insulated stainless steel and featured twin-branch delivery to the catalysts: one main branch to a ceramic matrix catalyst and one by-pass branch to steel matrix catalysts. The by-pass branch only comes into play at high speeds in response to the opening of a throttle valve controlled by the Motronic system. This optimizes engine performance by reducing exhaust back-pressure.

The F355's drivetrain featured a 6-speed transverse gearbox or an optional F1 electro-hydraulic transmission system with paddle shifters, derived directly from current Formula 1 technology. The manual, all-synchronized system offered short travel through the classic Ferrari gated shifter actuating rigid rods for a positive feel. The ratios were designed to make the most of the torque curve, thereby enhancing the driveability and sporty performance of the car. The differential was a multi-plate limited-slip type with segmented lock that adopts a differentiated drive and over run. The single dry plate clutch was hydraulically actuated, its housing being magnesium alloy. A water/oil heat exchanger ensured the gearbox oil was rapidly brought to optimal operating temperature.

Ferrari's 6-speed F1 electro-hydraulic transmission, debuted on the F355, signaled a new era in drivetrain design and performance. The driver shifts a sequential system controlled with paddles behind the steering wheel, exactly as on a Formula 1 car. There is no clutch pedal. The system has four driver-selectable modes of operation: sport, normal, auto, and low grip. The Ferrari 'Fl-type power train management' is the best solution for racing and road use. The system guarantees almost instantaneous gear changes, allowing the driver's desired gear to be engaged without either taking the hands off the wheel or operating the clutch, even during hard cornering. For safety, it is impossible to avoid engaging intermediate gears during rapid downshifts. The system can be used in a fully automatic mode without impacting fuel consumption, and the software that controls the system is integrated with other systems in the car to increase control in varied conditions.

Source - Ferrari