Porsche Cayman GT4 and Boxster Spyder revealed

UPDATE 18/06/2019 9:00am: Porsche Cars Australia has confirmed local pricing and specifications for the Porsche Cayman GT4 and Boxster Spyder -- see below.

Porsche has confirmed a nearly all-new naturally-aspirated 4.0-litre six-cylinder boxer engine will power the new Porsche Cayman GT4 and Boxster Spyder, both of which were revealed overnight.

Due to be launched at the Goodwood Festival of Speed early next month, before arriving in Australia early next year – when the Porsche Boxster Spyder will also be available here -- the Porsche Cayman GT4 is effectively a road-going version of the race-ready Cayman GT4 Clubsport revealed in January.

However, the first road-going 718 Cayman and Boxster to be available with a six-cylinder engine rather than a turbocharged four-cylinder won’t be fitted with the Clubsport’s normally-aspirated 3.8-litre boxer six — or the 4.0-litre atmo six in the 911 GT3 RS.

In proof that Porsche remains committed to the naturally aspirated engine, the director of Porsche GT Road Cars Andreas Preuninger told carsales.com.au the new 4.0-litre non-turbo boxer six was based on the 911's latest turbocharged 3.0- and 3.8-litre boxer engine.

“We found the sweet spot at the first run,” said Preuninger at a recent technical workshop for the new Cayman GT4 in Germany.

“It’s got a 4.0-litre naturally-aspirated flat-six. It's got roughly the same outline as a [911] GT3 engine, so it's 81.5mm stroke and 102mm bore. So it's the same dimensions but it's bit of a derivative of the turbo engine, what we call the 9A2,” said Preuninger.

It might be derived from the 911 Carrera’s turbocharged engine, but the powertrain engineers say the engine in the new range-topping Cayman and Boxster models, which share their powertrain for the first time, is at least 80 per cent new.

There’s piezo injection, a dry sump and adaptive cylinder control, while the exhaust has the necessary petrol particulate filters to pass current and future emissions regulations.

There’s also an idle-stop system -- the first in a Porsche GT car -- requiring a larger starter and battery. Power is rated at 309kW at 7600rpm, peak torque of 420Nm is delivered between 5000 and 6800rpm, and Preuninger says “it spins to 8000rpm”.

Simply slotting in a GT3 engine, which produces up to 383kW/470Nm in the RS, wasn’t feasible -- not least because the race-focussed engine is expensive and difficult to manufacture, but because it would also have to be turned around for its mid-mounted location in the 718 platform.

De-tuning it isn’t the work of a moment either because, as Preuninger admits, the GT3 4.0-litre is an engine that needs all its power to work properly.

Preuninger said he could not deny hearing “the roar of the crowd” in favour of a flat-six in the latest Cayman GT4, and confirmed he was already looking in the direction of a normally-aspirated engine for the future -- despite it flowing against the industry norm.

“We needed a different platform for the GT4 and we are quite happy that everybody in the industry is giving up on normally-aspirated engines,” he said.

This new 4.0-litre is the response. It is able to be built alongside the regular Carrera engines, meaning the GT4 and Spyder can run simultaneously alongside the GT department’s other models and, crucially, without limited production.

The purists will be happy too, that Porsche has stuck with a manual transmission (six-speed, not seven), fitted with selectable auto-blip should you want the electronics rather than your feet to rev-match downshifts.

“We stick to the stick shift. Which is part of the equation that works so well in the customer's view,” said Preuninger.

“We think the package is quite about right for being the smaller brother of the GT3 with a little bit of a different positioning. The GT4 is a driver's car. It welcomes any novice, but it satisfies all the purists, as well as the track guys.”

Even so, being a GT product, inevitably track times will be discussed. But Preuninger says it’s not a car that’s as singularly focussed on track driving as the GT3 might be, but still hugely capable.

The Porsche GT boss claims the Cayman GT4 will lap the Nurburgring at least 10 seconds quicker than its predecessor. That means it’s as fast as -- if not faster than -- the 991-series 911 GT3 around Germany’s most famous track.

“It is quicker than the predecessor; it's about a second [quicker] to 200km/h from a standstill. It will be substantially quicker around the ‘Ring because of all the new electronics, all the new damper technology, the aero, the whole package, the steering, everything … so it comes together as one whole.

“You know from the generation that jumps in on the 911. We don’t change obviously so much and everybody gets out of the car and says ‘wow it's a completely different car’. It's similar here and you will really appreciate that when you drive it.”

The official numbers are a 0-100km/h time of 4.4 seconds for both models and a top speed of 304km/h for the Cayman GT4 -- Porsche's entry-level GT model -- while the third-generation Boxster Spyder can reach 301km/h.

Aerodynamics inevitably play a significant role in achieving the faster lap time. Visually the Cayman GT4 looks little similar to its predecessor, the adjustable front splitter and rear wing having only minor detail changes rather than wholesale revisions.

Where it gains is underneath, with the addition of a large diffuser. For that GT4 owners can thank Spyder buyers, as it needed to achieve downforce without the old GT4’s fixed wing (the Spyder's wing pops up at 120km/h).

“We had to look elsewhere for making the downforce, which is the under body. The Spyder needs it more badly than the GT4 because it was quite OK as it was. But we can always live a little bit more,” said Preuninger.

The result is a 50 per cent gain in downforce, which has been achieved without any penalty in drag. The aero changes in front of the front wheels help clean up the airflow down the side, and to vent pressure in the wheel wells.

Collectively, Preuninger says that gives the Cayman GT4 the type of downforce that “is GT3 bandwidth at the moment.”

That aero pushes down on suspension that’s derived from its rear-engine GT relation, too, with ball-jointed upper mounts and manually adjustable toe, camber and anti-roll bar settings should you want them at the track, plus a pair of modes selectable via a button in the cabin for the PASM (Porsche Active Suspension Management) dampers.

The sports chassis sits some 30mm lower than any regular 718 model’s, and both the GT4 and Spyder get the same chassis set-up.

Indeed, unlike the previous Boxster Spyder, the open-top car is a proper GT product “like an open GT4”, in a similar vein to the recent 911 Speedster — a car the GT boss and self-confessed convertible fan personally pushed for.

Tyre sizes remain the same as the previous GT4, so there’s Michelin Pilot Sport Cup 2 rubber measuring 245/35 ZR20 up front and 295/30 ZR20 at the rear, on newly designed lightweight alloy wheels.

The wheels retain five lug bolts rather than the centre-lock wheels of its GT3 relatives, in another concession to keeping the price as accessible as possible.

There’s the option of PCCB (Porsche Ceramic Composite Brakes) if you’ve deeper pockets and want to reduce the unsprung mass slightly.

The climate control and infotainment system have been deleted and the options list contains to ability to remove more mass via the addition of lightweight carbon-fibre bucket seats.

A Clubsport package — with the usual rear steel roll cage, fire extinguisher, six-point driver's harnesses and ignition kill switch — will be offered optionally too, depending on the market.

If its predecessor was criticised in one area it was usually the gear ratios, which remain unchanged. Preuninger explained that the long ratios are necessary to allow it to pass global emissions standards.

Overall, weight has increased to 1420kg, but Preuninger is quick to point out changes in the way homologation vehicle weights are legally measured.

Cars must now be homologated without any weight-saving options ticked, so “this car nominally is about 60 or 80 kilos heavier on paper, but it's only about 30 kilos heavier in real world if you compare apples to apples,” said Preuninger.

Regulations also take their toll here, with the Cayman GT4 and Boxster Spyder now featuring necessary, and weighty, technologies to pass stricter emissions regulations.

“I can absolutely assure you it doesn't feel half gram heavier than the car before,” promises Preuninger.

We’ll be able to let you know very soon whether that’s the case.

The Australian order book for the 2019 Porsche Cayman GT4 and Boxster Spyder opened today, ahead of first deliveries by March 2020.

Prices startat $209,000 for the roadster and $218,800 for the coupe, which makes Porsche's new mid-engined flagships almost as pricey as the cheapest 911s.

It also sees the Cayman and Boxster swap positions at the top of Porsche's compact sports car range, which was previously led by the Boxster GTS at $175,500.

While the $209K Boxster Spyder eclipses that price by $33,500, the $219K Cayman GT4 is over $46,000 more expensive than the Cayman GTS ($172,700 plus ORCs).

However, apart from the powertrain, chassis and aero kit, extra standard features for Australia will include tinted bi-xenon headlights including Porsche Dynamic Light System, ParkAssist including reversing camera, automatically dimming mirrors with rain sensor, windscreen with grey top-tint, ambient interior lighting, alarm system, Apple CarPlay, Porsche Connect navigation, digital radio, cruise control, two-zone climate control, heated seats and, for the Spyder, a heated multi-function steering wheel.