It’s been 40 years since Porsche last entered sports car production with a four-cylinder engine, then powering the 912E, so the Boxster's new powerplant is a significant focus shift from the previous flat-six engine.
Despite not having used engines with four cylinders in a sportscar for so long, Porsche is adamant its history with the platform means it knows how to best extract performance out of such an engine. The opposed four-cylinder design assists with packaging, weight distribution and a low centre of gravity. Likewise the adaption of turbocharging, an art the German marque knows a lot about.
"We have different expectations to meet," Bruno Kirstner, the mechanics manager of Boxer engines told us. "Those expectations include emotion - or the sound from the exhaust - performance and economy."
Kirstner is adamant the four-cylinder boxer engine is free revving, delivers on the promise of a low centre of gravity and delivers super fast response to throttle inputs as well as everyday usability.
The new engines are smaller, more powerful and more efficient than the engines they replace, following the recent trend Porsche started with the smaller capacity 911 engines. Both the 718 Boxster and Boxster S benefit from power and torque increases, with torque especially growing from the addition of turbochargers.
Interestingly, the new four-cylinder engines were developed alongside the new six-cylinder engines that power the 911 Carrera and Carrera S, and as such benefit from some of the same technological improvements for components like drive belts, connecting rods and the water pump. The new engine is also lighter than the old six-cylinder, by 8.1kg in total.
The boxer platform even allows Porsche engineers to further improve the mounting position of the turbo and therefore the air intake and exhaust systems as well. It assists with thermal management, operating efficiency and cool down time.
"To ensure we have adequate air coming into the system, we had to revise the design of the intakes forward of the rear wheels," Kirstner said. "The benefit of this is the intakes look more aggressive in a styling sense."
The 718 Boxster will generate 220kW and 380Nm from its 2.0-litre four-cylinder turbocharged engine, with peak torque available between 1950-4500rpm. That figure represents a significant torque increase of 100Nm over the old model.
"Any new Porsche engine must deliver incredible driving experience and throttle response," Kirstner said. "This includes something we call 'turbo rightsizing' which ensures the turbocharger best matches the engine capacity and we want that turbocharger to do."
The 718 Boxster S makes 257kW and 420Nm (a 60Nm increase) from its 2.5-litre four-cylinder turbocharged engine. The peak torque figure is available between 1900-4500rpm. For the Boxster S, Porsche has opted for a turbocharger with variable turbine geometry.
According to the German manufacturer, that means it is the ‘only manufacturer to implement VTG technology in production models with petrol engines’, those being the 911 Turbo and 718 Boxster S. Kirstner admits Porsche did consider a twin-turbo system, but settled on a single turbo design given the operating efficiency and the performance generated.
The power figures are just as impressive as the torque figures too, with both engines generating 26kW more than the previous model. Porsche quotes the torque increases as the ‘largest ever achieved by the introduction of a new engine in the history of the Porsche Boxster’.
Both Boxster models are available standard with a six-speed manual transmission, with Porsche’s desirable PDK optional. As you’d expect, the increase in power and torque for both models ensures both are faster than the model they replace.
The Boxster (with PDK and Sport Chrono) sprints from 0-100km/h in 4.7 seconds, while the Boxster S (with the same equipment) completes the sprint in 4.2 seconds. Top speeds are 275km/h and 285km/h respectively.
Despite the performance increases, new Boxster is more efficient (up to 13 per cent more) with a European claim of 6.9 litres per 100km for the PDK equipped Boxster. A Boxster S with PDK will consume only slightly more despite the larger engine , at 7.3L/100km.
Porsche promises that, like the six-cylinder engines we’ve tested recently in Carrera and Carrera S, the new four-cylinder engines will feel decidedly unlike normal turbocharged engines, delivering linear power, sharp throttle response and free revving characteristics right up to their 7500rpm redline.
"We believe this all-new engine delivers and exceptional blend of power, performance and efficiency," says Kirstner.
The 718 Boxster and Boxster S models will be priced from $113,100 and $143,400 respectively, both plus on-road costs. These figures represent price increases of $8400 and $12,300 respectively. Order books are now open.
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