Article: EVO Magazine UK

The Porsche Cayman GT4 is perhaps the most anticipated new performance car of 2015. Why? Simply because this is the car that should finally demonstrate the full potential of the brilliant Cayman mid-engined chassis. Up until now there’s always been a suspicion that Porsche’s mid-engined sportscar has been held back to avoid embarrassing the 911, but with the GT4 all that hierarchical baggage seems to have been discarded.

Developed by Porsche Motorsport – the same engineers who’ve given the stunning line of 911 GT3s, the mad GT2 RS and, of course, the RSR racecars – and benefiting from a host of 991 GT3 components, the Cayman GT4 is a mouth-watering proposition.

The headlines you need to know are as follows: 3.8-litre flat-six from the Carrera S developing 380bhp at 7400 and 310lb ft from 4750rpm-6000rpm, 1340kg, 6-speed manual gearbox only (although PDK may be offered in future), GT3 front suspension components, GT3-spec brakes, much improved aero that delivers similar downforce to the GT3 and a promise that the GT4 puts fun and involvement ahead of everything else.

Andreas Preuninger, Head of GT cars, is positively beaming about Porsche’s new baby: ‘This is a completely new concept for the Cayman,’ he says, ‘and because we don’t have any real rivals we’ve been able to concentrate on fun driving dynamics rather than target certain lap times or acceleration figures.’ That said, the GT4 hits 183mph, 0-62mph in 4.4-seconds and will lap the ‘Ring in 7-minutes 40 seconds.

Oh, and the best bit. The Cayman GT4 will cost from £64,451. With all that GT3 hardware and a Carrera S engine. If you haven’t already got one of these cars on order, then be prepared for a long wait or to pay a hefty premium…

Engine

The GT4 borrows the 3.8-litre flat-six from the Carrera S but with a unique tune by Porsche Motorsport and a redline of 7800rpm. Power is 380bhp at 7400rpm and there’s a strong 310lb ft available from 4750rpm-6000rpm. However, Preuninger has a twinkle in his eye when he tells us, ‘It’s 385 but it’s GT horsepower so it’s at least 385bhp at an elevation of 10,000-feet or 40-degrees celsius… I’m kidding you but we’re always conservative about our figures. 385ish… but it feels more.’ The engine isn’t dry-sumped like the GT3 engine but Porsche claim that even under extreme duress on the circuit that oil starvation will not be an issue.

Gearbox

‘Since the 991 GT3 came out there was a lot of clientele that wanted to shift manually, to get involved. They don’t care too much about the last tenth. We listened to them,’ begins Preuninger when explaining why the Cayman GT4 goes back to basics with a 6-speed manual ‘box.

‘It’s about emotion, about being involved and having a car that talks to you and this is what we’ve combined with a very, very competent track capable car.’ Sounds good to us. The GT4 retains the gearing of the Cayman GTS – which we found to be very tall at eCOTY – but with considerably more torque Porsche claim it pulls the gears very convincingly indeed.

Even so, we’d love to have seen shorter ratios to enjoy that 7800rpm redline as often as possible. The GT4 also has unique software for the automatic downshift blip. Like other Porsches with a manual gearbox the downshift-blip doesn’t function when PSM is fully disabled, giving complete responsibility to the driver. We like that. The GT4 also has a new dual-mass flywheel that’s almost as light as a single-mass item, according to Preuninger.

Chassis

This is where things get pretty trick. The Cayman GT4’s front suspension is borrowed almost entirely from the GT3. It utilises forged aluminium split wishbones so shims can be added for those looking for a pure track camber set-up, the same aluminium inverted dampers from the GT3 and 45Nm front springs (the rears are 80Nm) – a little less aggressive than the GT3. The roll-bars adjust between three settings and again are shared with its big brother.

At the rear it’s almost all-new, again with aluminium wishbones and also height adjustable dampers and a helper spring. The GT4 also has a mechanical limited-slip differential – not an e-diff as on the GT3, but it does have the Torque Vectoring system that brakes an inside wheel to reduce understeer. The Cayman GT4 also does without the rear-wheel steer function of its big brother.

Electronically adjustable PASM dampers offer two modes – Normal and Sport. Lots of work has also been done on the electric power steering system. The new software tune is said to offer even more precision and feel than that of the GT3… In fact Porsche are pretty excited about the steering feel delivered, which we really look forward to sampling.

The GT3 does have a great electric steering system but it’s still lost the intimacy and detail of the old hydraulic set-up. If the GT4 can bring back some of that texture and nuance it could be a step change for these types of set-ups. The GT4 also comes as standard with Dynamic Engine Mounts.

The GT4’s 20-inch wheels are forged and look similar to the GT3’s but they’re not centre locks. The hubs are taken from the 991 Turbo. Tyres are Michelin Pilot Sport Cup 2s, 245-section at the fronts (the same as the GT3) and unique 295s for the rear. Overall the car is 30mm lower than a standard Cayman.

Aerodynamics

‘Our target was to have a zero lift car,’ explains Preuninger. ‘But we ended up having as much downforce as the GT3, so around 100kg at top speed. That’s quite substantial and you really feel it.’

Brakes

No messing around here. The GT4 uses exactly the same set-up as the GT3. So that’s 380mm discs and 6-piston calipers at the front and 380mm discs with four-piston calipers at the rear. PCCB carbon-ceramic brakes are an option with vast 410mm discs. ‘I would say it’s gently over-engineered,’ quips Preuninger with a smile. Considering that the Cayman is 90kg lighter than the GT3 we’re pretty confident that stopping power won’t be an issue!

Performance data and 0-60 times

The GT4 might not be a car that will be defined by numbers but that’s not to say it’s not searingly quick. Porsche claim 0-62mph in 4.4-seconds and a top speed of 183mph. The Nürburgring lap time isn’t fully optimised yet but Porsche are claiming a 7:40. It might even sneak under that when the final time is set in April.

Price (UK)

Like the 991 GT3 before it, the GT4 seems a bit of a bargain. This car has plenty of GT3 underneath (£100,540), a Carrera S 3.8-litre engine (£83,545) yet it’s lighter than both, has superb aero balance and every little detail has been tweaked by Porsche Motorsport – even stuff like the wheel wells and wing mirrors. Yet it costs from just £64,451. Although you might want the optional carbon fibre seats. The Clubsport package (which includes a fitted half cage, you get the front bits should you want to fit them and go the whole hog) is £2670. Just do it.