We compared Porsche Cayman engines, and the efficiency crown goes to…
Sports car buyers aren’t necessarily very concerned about engine efficiency, because sports cars are luxury items with owners who seldom worry about annoyances like the fuel price. But think about this: the more efficient a car is, the longer it can be enjoyed without tedious fuel stops. With this in mind, we look at the current Porsche Cayman range, to determine which engine is the most efficient.
Is smaller really better?
The current Porsche 718 Cayman range presents an interesting mix of powertrain options, with a selection of manual- or dual-clutch automatic (PDK) transmissions, two 4-cylinder turbo engines, and a large-displacement naturally-aspirated 6-cylinder unit (in two states of tune) on the menu. Rather than diminishing the character of the Cayman when it received the new, boosted engines in 2016 (along with a name change to 718 Cayman), the turbo powerplants instead offered improved efficiency and extra torque, even if it's at the cost of some reduction in aural charisma.
Related: Get the details about the 718 Cayman’s downsized engines here.
But Porsche quickly reacted to the mixed emotions evoked by the new flat-four engines’ soundtracks, first releasing a GTS version with a more-powerful and better-sounding flat-four, and eventually unveiling a new-generation Cayman GT4, again with a detuned version of the 911 GT3’s naturally-aspirated, 4.0-litre flat-six engine. This engine has now also trickled down to the Cayman GTS, albeit in a lower state of tune. But how do the turbo 4-cylinders compare to the non-turbo 6-cylinders? Let’s evaluate the entire model range to find out.
Porsche 718 Cayman
This is the entry-level variant in the Cayman range, and is available with either a 6-speed manual or a 7-speed dual-clutch gearbox with the same pricetag. But, seeing as the 6-cylinder cars in the range can only be had with manual transmissions, we’ll keep this comparison between manual gearbox-equipped Caymans.
As the baby of the range, the base Cayman (and related Boxster) receives the smallest of the two new turbo engines. It displaces 2.0-litres, and produces 220 kW and 380 Nm. Both figures are up considerably on its 6-cylinder predecessor’s outputs of 202 kW and 289 Nm, and give the Cayman a solid shot of sporting credentials even at the bottom of the range.
Average fuel consumption - combined cycle (manufacturer’s claim):
7.4 ℓ/100 km
Estimated fuel range:
730 km
Porsche 718 Cayman S
The sportier 4-cylinder Cayman S benefits from a number of upgrades over the range opener. Its flat-four engine grows from 2.0- to 2.5-litres, and gains a more advanced variable-geometry turbo (VGT) to give sharper throttle response and more power. Incidentally, Porsche was the first manufacturer to fit a VGT to a mass-market production petrol engine, a feat made possible by advances in modern materials- and manufacturing technology.
Related: Which Porsche 718 Cayman trim depreciates the fastest?
As applied to the 718 Cayman and Boxster, this flat-four develops 257 kW and 420 Nm – yet again a handy increase on its 6-cylinder predecessor’s 239 kW and 370 Nm. It must be noted that the 2.5-litre is capable of producing a fair bit more power than its standard software allows, so the buyer of a pre-owned (and out-of-warranty) 718 Cayman S may want to investigate a software upgrade to unleash this engine’s full potential. Also note that, according to Porsche’s own website, the Cayman S (and all high-trim Caymans) has a 64-litre fuel tank instead of the non-S Cayman’s 54-litres. Strange.
Average fuel consumption - combined cycle (manufacturer’s claim):
8.1 ℓ/100 km
Estimated fuel range:
790 km
Porsche 718 Cayman GTS 4.0
This one is a bit of an enigma, really: at the time of writing, the 718 Cayman GTS 4.0 cost R9 000 less than the 718 Cayman S, yet it’s a superior machine in most respects. This is the less-expensive 6-cylinder 718 derivative, and draws its ample power from a 911 GT3-derived 4.0-litre, non-turbo engine. Interestingly, this GTS variant was preceded by one with a 2.5-litre 4-cylinder turbo in a higher state of tune, but this was soon replaced by the 4.0-litre in response to customer demand.
Related: New vs old Porsche 718 Cayman GTS: what are the 4 main differences?
While the GTS 4.0 has the same maximum torque output as the Cayman S, that torque peak occurs much higher up the rev range (from 5 000 – 6 500 r/min). As a result, there’s quite a bit more top-end power on tap, with its peak of 294 kW coming along at 7 000 r/min. Exclusively matched to the 6-speed manual gearbox, the Cayman GTS 4.0 has the charisma and performance that befits a flat-six Porsche at a relative bargain price, but at the expense of much greater fuel thirst.
Average fuel consumption - combined cycle (manufacturer’s claim):
10.8 ℓ/100 km
Estimated fuel range:
602 km
Porsche 718 Cayman GT4
This is the wildest Cayman on offer, and receives a number of handling- and aerodynamic enhancements from the 911 GT3. As with the GTS, there’s a 4.0-litre non-turbo flat-six engine mounted in the middle, but it’s tuned a bit differently for this application: peak power goes up to 309 kW (at 7 600 r/min), but it has the same torque output as the GTS (and Cayman S), with 420 Nm available from 5 000 – 6 800 r/min.
Average fuel consumption - combined cycle (manufacturer’s claim):
10.9 ℓ/100 km
Estimated fuel range:
596 km
Related: Fit for the racetrack – we tell you everything about the Porsche Cayman GT4.
Verdict:
There can be no doubt that the new 4-cylinder engines are vastly more efficient than the two 6-cylinders. Comparing the Cayman S to the GTS reveals very similar performance levels, but with an average consumption advantage of more than 2.5 ℓ/100 km in favour of the 2.5-litre. Of course, none of these cars will return their claimed figures in real-world driving, but the smaller engine’s greater efficiency is just too significant to ignore.
But which of the two 4-cylinders would we recommend? The bare figures suggest that the base 718 Cayman will drink the least of the two, but is it worth sacrificing so much performance to score a comparatively small consumption victory in a sports car? Some buyers will be happy to make that trade-off, and enjoy the already-strong performance on tap in the base variant. But enthusiasts will likely find a better balance in the Cayman S, for near-six cylinder performance without the attendant profligate drinking habits. If only the flat-four could be made to sound as good as a howling flat-six...
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