February 29, 2016 @ 12:45 PM

First Look: Porsche 718 Boxster — Powertrain

Porsche flew us all the way to Marseille to check out their brand new flat-four engine in the Porsche 718 Boxster.

Just as how all new 911 Carrera engines have given up on being naturally aspirated, so do the boxer engines of the new Porsche 718 Boxster. But the new engines go beyond than just slapping a turbo on the engine and calling it a day, it isn’t as simple as that. What was once a flat-six is now a flat-four and the displacement of the engine have also been downsized — or right-sized in Porsche-speak — from 2.7-litres to 2.0-litre for the standard 718 Boxster and 3.4-litres to 2.5-litres for the 718 Boxster S model.

Interestingly enough, it was revealed that China will have an additional engine to their lineup. Joining the new turbocharged engines will be a 2.0-litre boxer-4 with no force-induction whatsoever. The naturally-aspirated engine produces 250bhp and 310Nm of torque. All things considered, this reduced-performance engine still has more torque than the older-generation’s 2.7-litre flat-six.

Although the displacement has shrunk, the powerscale has been moved upwards. Oh joy! The 2.0-litre flat-four now produces 300bhp and 380Nm, up from the 261bhp and 280Nm of the 2.7-litre engine. Naturally, performance has also improved. With the PDK and Sport Chrono Package, the 718 Boxster goes to 100kph in 4.7 seconds, or 0.8 seconds faster than the previous generation car.

The output soars in the 2.5-litre boxer-4 of the 718 Boxster S — 350bhp and 420Nm vs 311bhp and 360Nm. With the PDK and Sport Chrono Package, the 718 S goes from 0-100kph in 4.2 seconds, or 0.6 faster than the previous generation car.

While the figures read differently, the 2.0-litre and 2.5-litre engines are nearly identical. Nearly, because the only differences are the bigger bore, larger turbine and compressor wheels, and variable turbine geometry in the 2.5-litre. And both engines can trace their lineage back to the 911 Carrera’s twin-turbo flat-six; minus two cylinders. In fact, the new engine shares many parts from the 911 — fuel pump, adjustable exhaust camshaft with valve stroke adjustment, VarioCam plus system, fully variable water oil pump and thermal management system with a switchable water pump. Even the cylinders have been coated with iron using the same plasma-vapouring technique. It had to be done because it lowers the friction of the engine and makes the cylinders strong enough to be used with lower-grade fuel.

Porsche reduces the heat by channelling the compressed air through a separate loop to the heat exchanger above the engine. Some of the heat will be shifted to the coolant, which then flows to the radiator to be cooled and ready for the next cycle.

And then, there’s the sound. Porsche understands that part of what stirs emotion is the sound the car makes and there were validated concerns that going to a turbocharged flat-four will rob the Boxster of its noise. Countermeasures come with the newly-developed exhaust system. The exhaust gasses from the four cylinders come together in front of the engine, then flows through the turbocharger and catalytic converter and rushes into the single exhaust line that runs past the engine only to be split up into two pipes before the transmission, then continues past the gearbox. The exhaust gets ejected, depending on the variant, through either a single oval or a twin round dual tailpipes. Optional sport exhaust system will enhance the noise. Because the exhaust rushes past the oil sump, which would make any standard plastic oil sump melt, Porsche has decided to go with an aluminium    sump, with modifications that can withstand lateral forces and ensures that oil is always on the level.

The change in size from six to four isn’t as simple as taking the new 911’s turbo-flat six, lop off two cylinders, mount it to the engine bay and call it a day. Additional parts that make up a turbocharging system gave the engineers the challenge to fit everything inside an engine bay that cannot be changed. Not only that, the new engine is also heavier than the previous one, which adds to the overall weight of the 718 Boxster. Having said that, the power it created is more than enough to make it better than the previous Boxster. And that’s the only thing that matters, yes?

Chris Ng

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