There was a feeling when the first Cayman GT4 arrived that it’d be something of a one-off. In a climate of downsizing, with the Cayman range itself known to be readying for a switch from flat-sixes to turbocharged flat-fours at the time, it didn’t seem likely Porsche would ever stick a big atmospheric engine in such a small car ever again.
Fast forward four years and I’m in a new version, which is currently on two wheels after taking a little too much kerb at Knockhill Circuit’s fabulously-named ‘Duffer’s Dip’ Turn 1. The 718 Cayman GT4 and I land back on the ground with a thump, eliciting an expletive from my lips.
It’s a full-on track, this place, and it’s not easy to focus on assessing the car underneath you rather. After all, the thought of how embarrassing it’d be if I stuffed it into the gravel on the exit of Scotsman, a turn that’s far tighter than it looks on entry, is quite distracting.
But get a grip I must, as there’s plenty to investigate here. Chief among which is the engine - rather than stick with the same 991.1 Carrera S 3.8-litre engine of the old GT4 (it wouldn’t be possible to make it emissions compliant), there’s an even bigger flat-six at play in the 718 version. The 4.0-litre ‘9A2 Evo’ is based on the 3.0-litre turbocharged six from the 992 911 Carrera S, although precious little is carried over.
There’s a new crankcase, new cylinder heads, a new crankshaft, new con-rods and new pistons, with the change in piston height giving the increase in displacement. It develops more power (414bhp) at a higher engine speed (7600rpm) and has a rev-limiter that cuts in slightly later (8000rpm).
It may be related to the standard 9A2 engine and made on the production line, but what’s hidden under the Cayman GT4’s nicely sculpted flanks is best considered as a brand-new naturally-aspirated engine. An all-new atmospheric six? What year is it??
It’s an anomaly. It’s inconceivable. It’s a glitch in The Matrix. Although the reality is, it ticks all the modern engine boxes it has to - with Porsche’s first shut-off system and a pair of petrol particulate filters added, it’s good to go for the next few years. We’ll leave you to speculate as to where else Porsche might use it - I’d say it seems unlikely that it remain in just the 718 Cayman GT4 and the closely related Boxster Spyder, given the work that’s gone into making it.
Inevitably, those fat PPFs in the exhaust system have affected the sound. From the outside, it sounds like quite a raspy thing rather than a screamer, and noticeably different from most other nat-asp Porsches. From the inside, it doesn’t have the same mid-range howl, nor does it sing quite as sweetly in the top end. But it’s still a peach of an engine.
It emits a more moody, muscular noise. It’s still clearly from the same family - it’s just the slightly scary uncle who spends far too much time in the gym.
The 9A2 Evo is also a more flexible engine than before, with an increase in torque lower down the range. It’s still at its best over 5000rpm, of course, charging up to that shouty 8000rpm redline with a linear attitude. And yes, throttle response is stellar. This is why we love natural aspiration.
Knockhill, while a daunting place, was a good choice of location for launching the GT4. Yes, the instructor-driven 911 GT3 RS I’m following has much more power than the GT’d Cayman, but stick the same pilot in each for a lap, and the GT4’s bigger, heavier bro isn’t going to be much quicker on this very technical track. The hottest of 718s gives you just about the right amount of power in a small, light, mid-engined frame.
The Cayman is already a good starting point to stick a bigger, pokier engine into, but more work is needed to make it deserving of the letters ‘GT’ on the boot. As with the last GT4, we have the front end of a 911 GT3, a completely bespoke rear suspension setup and standard-fit Porsche Active Suspension Management (PASM) adaptive dampers. It sits much lower to the ground than a regular Cayman, dropping 30mm in total. The final piece of the puzzle is a set of Michelin Pilot Sport Cup 2 tyres.
This all comes together beautifully. The 718 Cayman GT4 inspires confidence even as it’s being chucked around Knockhill’s scary corners (which is most of them), changing direction aggressively without a hint of understeer. The steering is another Porsche masterclass in electric assistance - it’s not excessively quick off-centre, it’s wonderfully natural-feeling, it’s perfectly weighted, and it provides the kind of proper feedback that sees the wheel kickback and writhe in your hands at times.
The GT4 is not an immovable object, however. Traction is not endless, with that new six providing enough go to make things move around at the rear. With the ESP turned off, it’s still a car you can lean on while being just the right amount of scary.
On the road, you get a greater sense of just how good the steering is. And how flat the GT4 corners - the body just doesn’t budge. It isn’t horribly stiff, however. Sure, you might find yourself staying away from the firmer ‘Sport’ chassis mode (the car flows a little nicer in ‘Normal’), but even enabled, you aren’t going to be in for a punishing time.
What is an issue on the road, however, is the gearing. It has the same six-speed manual gearbox as the last one, with the same infamously long ratios. So as joyous as that 8000rpm redline is, you won’t be sniffing around there all that often. Second gear tops out at 84mph, and third? You don’t want to be reaching the end of it unless you fancy finding out what prison food tastes like.
A B-road blast, then, usually involves the extensive use of second gear. On reaching national speed limit signs, you might find yourself slowing down and shifting to first, just to enjoy that lovely top end and the sweet, sweet short-throw shift of the manual. Heresy though this may be, I quite like the idea of the anticipated seven-speed PDK version, simply because it would enable more in the way of high RPM heroics.
You soon get used to the tall gearing, however, and it’s forgivable when really, it’s the only not so great thing about the GT4. As a sports car, it’s a triumph. As a £75,000 sports car, it’s a bloody bargain.
The one nagging thing in my mind is that all of this can be said about the old one. The engine is perhaps more interesting and the chassis is slightly sharper, but we’re not talking about a night and day difference. A refined version of the old one is what we all wanted, of course, but such a car isn’t going to have quite the same impact. Its thunder was stolen four years ago by the original. That it’ll be built for a longer period makes it seem less special, too.
Does that matter? Not really. This is a car that as many people as possible need to drive. Porsche making a new one is a kinda/sorta public service. The 718 GT4 is a lesson in less is more, yet it still provides an incredible amount of drama, pace and ability. It shouldn’t really exist in 2019. Be glad it does.