by Ian Kuah
GTS. These three letters, steeped in motorsport history, were first used on the sleek and petit 904 Carrera GTS of 1963, the car that took over the baton from the 718 that had contested the FIA-GT Class for Porsche since 1957. These days Porsche uses the GTS moniker across its mainstream range from Boxster to Cayenne, denoting an engine, suspension and trim specification that is sportier than the S, but not as hardcore as the GT models.
The GTS specification as we know it today was first introduced on the 997 Carrera in 2010, and was then rolled out to the Boxster, Cayman, Cayenne and Panamera ranges as well. The uprated engine specification comes from the factory power kit option in the case of the 911 models, with chassis upgrades usually being the optional sport suspension package, which is more than capable of handling the extra horses. Sport Chrono Package is also fitted to GTS models as standard. Aesthetically, black is the GTS trim color, which encompasses black tinting of the headlamp modules and taillights, black painted alloy wheels, rear apron.
In the cabin the black Alcantara steering wheel, gearshift level, armrest, and seat faces with red GTS logos stitched onto the headrests and red stitching on the black leather elsewhere make for an instantly recognisable theme. GTS models also get a distinctive front spoiler and the sport exhaust. The latest 718 Boxster and Cayman models have received mixed reviews. While the increase in power and torque delivered by the turbocharged flat four cylinder motors is widely appreciated, the clattery and offbeat 'Subaru-like' soundtrack has not.
Speaking to Matthias Hofstetter, Director of Powertrain for the 911 and 718 model ranges, I learned that Porsche has taken this criticism on board and is doing its utmost to improve the sound as the 718 range develops. "The issue is that the intake air pulsation of a flat-four under load is very difficult to handle and creates the distinctive sound that you hear," he says. "For the GTS model, we ended up designing a completely new intake system that has far less pumping losses, and we think a better sound as well." One of the problems of the characteristic air pulsation is the interference of each pulse with the next under high load conditions.
To alleviate this the engineers designed a baffle with two intake holes into their revised airbox design. Within the larger primary chamber this helps to stop the current of air from rushing towards the throttle body all in one go. It also holds back some of the air so that when you come off the throttle and then go back into it you have a reserve of air under pressure to help overcome any response lag. The next modification is to the turbocharger, which benefits from a compressor wheel enlarged from 64 to 67 mm in diameter. The turbine wheel, VTG system and wastegate are unchanged. The ECU mapping is revised to manage these physical upgrades, which means recalibration of the ignition, fuel injector timing and so on.
Boost pressure is 18.13 psi (1.25 bar). Compared to the S models on which the Boxster and Cayman GTS are based, power of the 2.5 litre flat four cylinder single turbo motor goes up from 350 hp to 365 hp at 6,500 rpm, with torque peaking at the same 317 lb-ft from 1,900 to 5,000 rpm for the seven-speed PDK transmission and 310 lb-ft from 1,900 to 5,500 rpm with the six-speed manual. Thanks to the improved efficiency of the new intake and turbocharger arrangements, the counterpoint is 10 percent improved fuel economy in normal road driving.
Incidentally, the peak torque numbers coincide with the respective torque limits for the two gearboxes, while according to Matthias Hofstetter, the extra 500 rpm 'overshoot' programmed into the torque curve for the manual gearbox is to partially compensate for the slower upshifts performed by a human driver compared to the PDK. On the subject of gearboxes, Matthias told me that while 981 Boxster/Cayman customers were split nearly 50-50 between manual and PDK transmissions, the 718 cars have seen a decisive move towards PDK with a 70-30 ratio. In fact, as PDK is the definitive gearbox for sheer speed and fast lap times.
On track he expects an even greater PDK take up rate with the more highly focused GTS models. The combination of engine and chassis upgrades make the Boxster and Cayman models decisively more rapid on both road and track, and on the Nurburging the new 718 Cayman GTS set a lap time of 7:40 min, a good 13 seconds quicker than its predecessor, and 2.0 seconds faster than the 718 Cayman S. Against the stopwatch, 60 mph comes up in 4.1 sec for the PDK version, with the manual taking 0.4 sec longer. 0-100 mph takes 9.3 sec and 9.6 sec respectively, with both variants pegged out at 180 mph.
While the 15 extra horses do not seem like a lot on paper, the new intake makes a noticeable difference to throttle response, and it is clear from the word go that the GTS spec motor is more lively and willing to rev. Pickup is crisper and the motor gets cooking with gas sooner, revving faster and more enthusiastically to the red line and on towards its 7,500 rpm limiter. The motor zooms round the clock with more ease and gusto than ever, encouraging you to explore the last third of the rev band more frequently. While this makes for a more engaging drive on the road it is a very valuable trait on track as I quickly discovered at the Ascari Circuit in Malaga, Spain.
The gearing of the PDK version is almost perfect for Ascari, while the strong mid-range torque means you don't always have to pick a lower gear for some of the slow or medium speed bends. At the same time when you do wish to extend the motor all the way it is quite willing to rev beyond peak power without stress. The GTS chassis settings really come into their own on a technical and demanding track like Ascari, whose 26 bends (13 left and 13 right) also feature a few elevation changes along the way. The three-quarter inch (20 mm) lower ride height of the sports suspension that's optional on the S model encompasses shorter, sport springs, matching dampers, and uprated anti-roll bars.
To ease logistical issues, Porsche has cunningly created stiffer anti-roll bars of the same diameter as standard by using steel with different characteristics. This obviates the need for different mounting hardware and saves additional costs. The black painted wheels and tires are the same size as on the S, which means 8.0J and 10.0J x 20-inch, shod with 235/35ZR20 and 265/35ZR20 tires. This uprated chassis set-up confers immense stability and balance on the Cayman GTS at speed, and you can confidently move the car into gentle four wheel drifts on the limit or hang the tail out on slower bends with impunity.
Trail braking into a slow bend allows you to rotate the tail gently to aim the car into and out of the bend with great precision thanks to its progressive nature. Every intention of the pointy front end is clearly telegraphed by the superb electric power steering. My test car had the optional PCCB ceramic brakes, and stability under hard braking is really tested to the limit coming off the flat out back straight towards Sebring, a slow uphill right hander that leads to Piff Paff, which you can straight line before turning into Spa. Then it is a roller coaster ride in third and fourth through Petit Eau Rouge and Daytona back towards the Start Finish straight. A very challenging sequence, but very enjoyable in a car with such a big confidence window.
The 718 Boxster GTS is another adventure by itself. Out on the road it is the quintessential roadster with a noticeably stiff structure that does not wobble on poor surfaces unlike some of its competitors. Here the relatively comfortable ride and sharp chassis and steering responses coupled with strong performance deliver the thrill of open top driving in a very focused form. While you can go point to point very rapidly in the 718 Boxster GTS, when you have a blue sky and warm sun above and the open road ahead as we did on our test drive, you actually want to throttle back and just enjoy the drive.
An open car is thus a throwback to the early days of motoring when people remained up close and personal with nature and enjoyed travelling while soaking up the view. The 718 Boxster and Cayman GTS represent the pinnacle of the mid-engine Porsche roadster and coupe genre. While they may appear similar on paper, their driving focus is so different that you might well want to consider them as a set. The Boxster for the road and the Cayman for the track would really be a perfect solution.