More than a Boxster coupe, less than a 911. That’s the official line on the new Porsche Cayman S which has major components from both models. The Cayman is powered by a 3.4 litre flat-six, which comes right in the middle of the existing range of engines which goes from 2.7 to 3.8 litres. Although the Cayman S is based on the Boxster,the body has been changed quite a lot to give it a different look – and that has succeeded. It is barely larger than a Boxster, though.
It is a fastback coupe in the Porsche tradition, but the fastback slopes down quite quickly emphasising the upward sweep of the fenders over the rear wheels. From the side, the Cayman S is unmistakably Porsche, and to distinguish it from the Boxster, the air intakes forward of the rear wheels are rather a different shape and have vertical louvres. The overall effect is good, and the new body clearly works; it has a drag coefficient of 0.29, which is slightly better than the 911 Carrera, and a very low figure.
The front is not far removed from the Boxster, but does have a pair of small lamps suspended in the outer grilles to make it look different.
The new lip spoiler at the front increases downforce at the front, and at the rear, a pop-up wing replaces the spoiler that comes up on the Boxster. Because it is specially shaped and is higher – 3 inches above the body – it gives more downforce, increasing stability.
So does it really fit in between the existing Porsches? The figures in the Table show it does, with the power, power-to-weight ratio and acceleration right between the Boxster S and 911 Carrera. However, the low drag coefficient and smaller frontal area of the Cayman S give it the edge over the 911 Carrera in top speed – by 1 mph. The power-to-weight ratio is also close to the bigger car, so in reality the performance will be very similar, except that the Cayman S should outcorner the 911 Carrera, thanks to the mid-engined layout.
Mechanically the Boxster and Cayman are very similar, sharing the same basic body, but with some different panels, and stiffened up by the coupe body. There is a very large tailgate to give good access to the surprisingly large luggage space at the back – there is also a reasonable luggage space at the front.
In fact, Porsche says that the body is twice as stiff as the Boxster, which is remarkable. Owing to this stiffness, the body will hardly flex at all while cornering or on bumpy roads, which will help the suspension and steering behave the way it is supposed to.
If the body flexes much, the suspension pivots move relative the body, resulting in poor tracking and suspension geometry – a problem with some cars, but certainly not with the Cayman S.
Strut suspension, very similar to that of the Boxster, is used. This is not ideal suspension for a sports car, but will work well on the Cayman S because it is stiffer than the Boxster, which already handles very well. Of course, both cars share the same mid-engined layout, which is the best set-up for good handling, as emphasised by Porsche in their information on the Cayman S.
This Porsche newcomer is designed to be more sporty than the Boxster. It will have sharper handling with less roll, the better aerodynamics will make it faster and more stable at high speed, and the engine has more power – 35 bhp.
To stiffen the suspension and alter the balance a little, a rebound stop spring helps to reduce roll. What’s that? During roll, the outer suspension spring is compressed, but the inner suspension spring stretches, and that stretch increases the amount of roll, because it releases energy. The rebound spring in the damper counteracts that force, so roll is reduced. These rebound stop springs also increase control on S-bends. So far I know, Toyota was the first to use these on the Lexus models.
That’s a refinement, but the springs, dampers and anti-roll bars are new. At the front, the anti-roll bar is about 10% stiffer, whereas the anti-roll bar at the rear is about 10% softer. On the other hand, the front springs are the same on both cars, but the rear springs of the Cayman S are 18% stiffer. This means that around the straight ahead position, there is likely to be a bit more understeer, but in other conditions, understeer should be reduced.
To further improve the handling, the Porsche stability control (PSM) is standard on the car, while PASM – active damping to you and me – is an option. I recommend PASM, which works well on the 911 Carrera.
The brakes are the same as those on the Boxster S and 911 Carrera, but there is the option of larger ceramic composite brakes with 13.78 inch (350 mm) diameter discs. These are 50% lighter than the cast iron discs, and are much less prone to fade. But they are expensive.
As standard, the tyres are 235/40 on 18 inch rims at the front, and 265/40 at the rear. You can have 19 inch wheels as an option, with the same 8 inch width at the front, but 9.5 inch, instead of 9 inch at the back.
There’s a new 3.4 litre engine in the Cayman S, but most of the parts are already in use in other engines, so small are the steps between the various Porsche power units these days. Based on the 3.2 litre unit, the cylinder heads are from the 3.6 litre 911 Carrera unit.
This results in big bores and a short stroke – 96 mm by 78 mm – with a new stiff crankshaft designed to rev up to the cut-off speed of 7,300 rpm. The new engine develops 295 bhp at 6,250 rpm, compared with 280 bhp at 6,200 rpm for the Boxster S, and 325 bhp at 6,800 rpm for the 911 Carrera. Hmmm. With that short stroke and the ‘S’ on the end of Cayman I would have expected more like 305-310 bhp at 6,500-7,000 rpm. So, it isn’t intended to be as sporty as the 911 Carrera.
Even so I’m sure that this will be as good as the other Porsche engines, partly because it has the latest VarioCam Plus system which has two sets of cams – one of low speeds and one for high speeds – and the opening point of the valves can also be altered. Torque is improved with the aid of a twin-plenum chamber intake system to give a ram effect to suit low and high-speed performance.
The result is better low-speed performance and fuel consumption, and more torque plus good top-end power. Therefore, maximum torque of 250 lb ft (340 Nm) is obtained all the way from 4,400 to 6,000 rpm. Dry sump lubrication ensures that there is plenty of oil at the critical engine components even during sustained high-speed cornering.
Although the six-speed gearbox is based on that of the Boxster S, it has new ratios from third to sixth, and also the excellent Porsche multiple-synchromesh.
What about the weight? Well, the Cayman S weighs 2,950 lb (1,340 kg) compared with 2,811 lb (1,275 kg) for the Boxster – 139 lb more. As the coupe top is added to the roadster body a weight increase is inevitable. The 991 Carrera, which is 3 inches longer than the Cayman S – not much difference – weighs 3,070 lb (1,395 kg) or just 120 lb more than the Cayman S.
So the Cayman S comes out pretty well, as Porsches generally do, despite the steel bodies, and we expect it to perform very well, too.