Porsche 718 Cayman GT4 review

And there’s a different sort of progress in the engine bay: an even better sort. At one point, Porsche toyed with the idea of equipping the Cayman GT4 with a highly tuned version of the downsized 2.0-litre turbo flat-four found in everywhere else in the Cayman range. But in Zuffenhausen, they correctly decided that wasn’t good enough, and so the new car gets an evolution of the 3.0-litre engine found in the current Porsche 911, only with the turbochargers sidelined and the cylinders substantially bored and stroked out. You read that right.

Understanding the GT4's new engine

The new 9A2 Evo unit is a 4.0-litre flat six that spins to 8000rpm, making 414bhp and 310lb ft along the way – an improvement of 34bhp over the old GT4, although torque remains the same (in fact, it arrives a touch later, at 5000rpm). It gets a forged steel crank, hydraulic valves and Piezo fuel injectors that improve propagation by making three individual – and presumably obscenely rapid – squirts for each stroke of the piston. Porsche can get the system working at 8000rpm but not at 9000rpm, which is why the 4.0-litre engine in the upcoming new GT3 won’t have it, and elsewhere there are low-friction roller cam followers instead of tappets. Below 3000rpm, this engine can also shut down a bank of cylinders for better fuel economy. Cleverly, it switches banks after a short while to keep the catalytic converters hot and operational.

On the road? We’ll have to wait. Sorry. That said, the suspension is encouragingly well mannered while trundling through the unevenly surfaced paddock at Knockhill, and if the old GT4 is anything to go by, the new car ought to ride just as many other mid-engined machines do: surprisingly, effortlessly well, particularly at the front axle, where the spring rates can be dialled back.

Alas, for now we’re limited to confines of Knockhill Racing Circuit, although given four in five owners will use their GT4 for track days, this is hardly an inappropriate place to get a first taste. It rained at lunchtime but now it’s dry, which is just as well, because if ever there were a circuit to provoke a car with even a morsel of inherent instability, this is it. There’s a looping, ducking sequence at the far side of the circuit that feels as though the car’s centre of gravity as been thrown in a tumble dryer, and even the opening right-hander is a tight, big dipper of a bend that flows over an adversely cambered crest. It’s taken way up into third gear.

But first the Cayman GT4’s driving environment. It’s recognisable from before, which is to say the ergonomics are borderline faultless in a fashion only McLaren currently seems to match. The car’s hip point is supposedly identical to before, but from our car’s optional carbonfibre bucket seats it actually feels lower, and even taller drivers can find a position whereby their eyeline almost skims the centre marker of the Alcantara steering wheel. That wheel itself is pretty sublime, too, hitting a sweetspot for diameter and rim girth and not having even a solitary button, toggle or scrolling dial to detract from its primary role. A touch more reach in the column is needed, but really that’s the only criticism. Maybe the steel roll cage that comes as part of the Clubsport pack hinders over-the-shoulder visibility, but it’s marginal. This is a wonderful, uncomplicated place to sit.

To sit and to get to work. On track, the driving experience itself will seem revelatory if you’ve never driven the old GT4 and curiously different if you have. Firstly, this is still a gold-plated five-star chassis with bells on it. The balance has an incredible self-centring feel about it, so even if you overcook it on the way into a bends or change course too abruptly, the car settles almost in an instant, quickly maximising traction and drive. 

This is probably the one major dynamic improvement over the old car, which simply wasn’t this stable, and when the grip ran out, you needed to act very quickly indeed. The new car’s roadholding is exceptional, but when you exceed those limits it’s the relative lack of steering correction required that takes your breath away. Confidence? Doled out by the bucketload, and more so when the two-way adjustable dampers are left in their more relaxed – and expressive – setting. We're not sure any other mid-engined series-production car communicates grips level this well. Again, maybe a McLaren, but none of the others.

The GT4's steering is another highlight, not least because the ratio isn’t hair-trigger quick, as seems the modern way, and the assistance has actually been dialled back a touch. The car turns in to corners with predictable accuracy and a delightful stability matched by the rear axle. The weighting is also linear, and alongside it the entire structure of the car seems to speak to you. The added benefit of a more considered ratio for the steering is that you can more easily coax the GT4 in corners with some attitude; you have time to think and feel your way in.

And the new engine? Objectively speaking, it’s good. Powerful and finger-clicking crisp in its response at the top end but smooth with its torque delivery at lower engine speeds and muscular enough to help diminish the effects of unusually long gearing (Andreas Preuninger apparently likes second as a proper driving gear; we think 85mph at the red line is a bit much), which remains unchanged from the previous model. Those ratios are still an issue, in truth, but engineering a new gearbox costs rather a lot, and Porsche wants to keep the cost of the car well below €100,000. While we’re at it, the clutch itself has been strengthened, but the pedal action feels a little lighter and less involving. Meanwhile, the short throw is a delight, and the fact the crucial movement across from second to third requires concentration to nail is, for us, only a good thing. There's a new auto-blip function, too. It's excellent.

How does the Cayman GT4 stand up against its rivals?

The Cayman GT4 costs around £75,000. You can then add the carbon-ceramic brakes for £5597, carbonfibre bucket seats for £3788 and the Clubsport Pack – which includes a roll cage, a 2.5kg fire extinguisher and a six-point harness – for £2778.

We'd go without the awkward harnesses, but even at more than £85,000 the GT4 seems fine value for money. The chassis is phenomenally good, and the braking, gearshift and steering are also all out of the highest drawer. For a similarly engaging mid-engined experience on track, you need to look to the likes of the McLaren 600LT and Ferrari 488 Pista. Best of all is that the production run will go on until 2022, with Porsche aiming to satisfy all orders and put an end to rampant speculation.

But here are the caveats. Firstly, we’re yet to drive this car on the road, where its gearing may well prove too long and the chassis too good even for this potent new engine. In the world of track day Porsches, if the GT2 RS is the one whose chassis (and, frankly, everything else) is dominated by its engine and the GT3 is the one where the entire show is in perfect harmony, the GT4 feels as though it needs a fraction more power to unlock its ultimate potential as a thrilling road and track car. That might happen in the form of a GT4 RS, but most likely it won't. The Alpine A110 could yet be the more engaging car on the road, and at little over half the price of the GT4.