Engine and transmission

New four-cylinder flat engines

In the 718 Boxster, Porsche is introducing two completely new four-cylinder flat engines with turbocharging. Their power and efficiency have been increased significantly compared to the previous engines. A bundle of innovations also ensures typical Porsche driving pleasure. The engines excel with more spontaneous response, free-revving properties up into the highest rpm ranges, and – not least – with their passionate sound.

Porsche is implementing the four-cylinder flat engines in two power versions: With two litres of displacement and 220 kW (300 hp) in the 718 Boxster and as a 2.5-litre engine with 257 kW (350 hp) in the 718 Boxster S. Compared to the previous Boxster models, this represents a power gain of 26 kW (35 hp) in each version. Engine torque has also increased considerably. The two-litre engine of the 718 Boxster has a maximum torque of 380 Nm, which is available from a low 1,950 rpm to 4,500 rpm. This represents a gain of 100 Nm or 35 per cent. The 2.5-litre engine of the 718 Boxster S reaches a torque of 420 Nm between 1,900 and 4,500 rpm; this is 60 Nm more than in the previous model. This is the greatest torque gain in the history of the Porsche Boxster.

Leap in torque: faster sprints from any speed

The new 718 Boxster models complete intermediate sprints with superior performance and accelerate even faster from low revs. The 718 Boxster with PDK and the Sport Chrono Package sprints from zero to 100 km/h in 4.7 seconds – 0.8 seconds faster than the previous model. The 718 Boxster S with the same equipment finishes this sprint in 4.2 seconds, making it 0.6 seconds faster than the previous model. At the same time, the engine has the typical free-revving properties of a sports car. The engine speed range extends up to 7,500 rpm, and the power decline from nominal to maximum engine speed is only five per cent. No other turbo engine in the market segment of the 718 Boxster can match this figure. When driving in a sporty style, the driver can fully utilise the engine’s power and torque over a broad range of engine speed without having to reach for the gear shift lever. And during full acceleration, the driver has the full torque of the turbo engine after a gear shift. Therefore, the effects of torque gains are especially noticeable in intermediate sprints within the speed range above 100 km/h. The top speed of the 718 Boxster is 275 km/h, and the 718 Boxster S can reach a speed of 285 km/h.

Power and efficiency with a turbo concept that has been turned up a notch

The turbo flat engines from Porsche impress with power and efficiency. The NEDC fuel consumption of the four-cylinder turbo engine with PDK in the 718 Boxster is 6.9 l/100 km, which is 0.7 l/100 km less than that of the previous Boxster. In the 718 Boxster S, the 2.5-litre turbo flat engine with PDK consumes just 7.3 l/100 km. This represents 0.9 l/100 km of savings compared to the previous model. The bottom line is 35 hp more power and up to 13 per cent better fuel economy.

The two versions of the new Porsche flat engine not only differ in their displacement. In the base engine, a classic wastegate turbocharger pushes additional air into the combustion chambers. The more powerful engine has forced induction by a turbocharger with variable turbine geometry that until now was a world exclusive feature reserved for the 911 Turbo. An additional wastegate in the 718 Boxster S operates the turbocharger with adjustable vanes to specifically control the exhaust gas stream to an optimal level of efficiency. It very efficiently converts the energy of the exhaust gas stream into drive power.

Same spontaneous response as a naturally-aspirated engine and Dynamic Boost function

In tuning the turbocharging process, Porsche developers placed a high priority on achieving engine responsiveness which is comparable to that of a naturally-aspirated engine. “Pre-conditioning” of the turbocharger in the part-load range is one of the ways in which a sporty style of driving is realised. The bypass valve is closed, ignition timing is retarded and the throttle is opened slightly. This keeps the momentary drive torque the same, while boosting air throughput in the engine and increasing charge pressure. When the driver then applies full throttle, the higher charge pressure spontaneously makes a higher torque available. Even if the driver briefly takes the foot off the accelerator pedal at full acceleration, the turbo engine reacts quickly like a naturally-aspirated engine. The throttle remains wide open, and only the petrol injection is stopped. As a result, charge pressure does not drop completely, and the engine can react spontaneously to another press of the accelerator.

The turbocharger responds in a comparable way to a push of the Sport Response Button. As in the 911 models that have the Sport Chrono Package and a PDK gearbox, it is located in the middle of the driving programme switch on the steering wheel. Inspired by motorsport, it prepares the engine and transmission for spontaneous responsiveness for a period of 20 seconds. In the part-load range, the wastegate of the turbocharger is closed. This results in a much quicker build-up of charge pressure. The engine responds more spontaneously to accelerator pedal inputs, and it reaches its maximum power faster.

Indirect intercooling via extended coolant circulation loop

Another innovation is indirect intercooling. To avoid having to change the design and aerodynamics of the 718 Boxster, the turbo engines use the lateral air intakes behind the doors to obtain their process air and now for indirect intercooling as well. The temperature is reduced by an auxiliary loop of the cooling system. This involves the use of a heat exchanger above the engine. In this heat exchanger, the compressed air from the turbocharger gives off some of its heat to the circulating coolant. The liquid then flows through one radiator per air intake.

Technologies from the three-litre six-cylinder twin turbo engines of the 911 boost the power and efficiency of these engines. They enable even finer adjustment of the turbo engine’s sporty, spontaneous response at low revs that is typical of a Porsche. The reason for this is that the adjustable exhaust camshaft with adjustable valve timing was introduced; it supplements the inlet camshaft adjustment familiar in the previous model.

Completely new exhaust systems for passionate sound

The newly developed exhaust system guarantees the passionate sound experience that is typical of Porsche. In the 718 Boxster, the exhaust gases flow through a system with a single oval tailpipe made of brushed stainless steel. The 718 Boxster S has centrally located round dual tailpipes made of brushed stainless steel. Two centrally located, round sport tailpipes characterise the optional sport exhaust system for all models.

Six-speed manual transmission as standard, optional seven-speed PDK

The 718 models come with a six-speed manual transmission as standard. The Porsche Doppelkupplung (PDK) is available as an option. To improve fuel efficiency, the PDK has the further advanced auto start/stop function, which already shuts off the engine when the car is coasting to a stop. The PDK also features virtual gears that save fuel. When driving at a constant speed, the controller chooses the highest possible gear. To stabilise engine revs and prevent jolts due to running at revs that are too low, the clutch of the relevant gear is disengaged slightly to allow a slight amount of slip.

Optimised Sport Chrono Package as option

The optional Sport Chrono Package improves the sporty properties of the new 718 Boxster even more. As in the 911, it now includes the Individual programme in addition to the three settings Normal, Sport and Sport Plus. From a specific menu in the instrument cluster, the driver can individually combine the PASM, sport exhaust system, auto start/stop function and rear spoiler based on programming settings for them. In sports cars with PDK, the Sport Response button is also added, which is located at the middle of the driving programme switch. Inspired by motorsport, pushing this button makes the response of the engine and PDK very direct – such as for overtaking manoeuvres. When the Sport Chrono Package is ordered, Porsche Stability Management (PSM) of the 718 Boxster models features a programme that can be activated separately: PSM Sport. In this very sporty driving programme, ambitious drivers can probe the limits of vehicle performance even further in a safe environment. The PSM always remains active in background. In combination with the upgraded Sport Chrono Package, this leads to a driving experience that takes the roadster even more in the direction of car racing.