Overview: Porsche Boxster Spyder

Eighty kilos lighter than the Boxster S, and with revisions to the engine, chassis, body styling and interior, the new Spyder is aimed at purists and minimalists. More specifically, it is aimed at purists who like driving without a roof or a radio.

Apart from substantial aesthetic changes to the rear of the car, there have been some minor aerodynamic adjustments. The Spyder’s Cd of 0.30 is the same as that of the standard car’s, though the frontal area is fractionally reduced.

Porsche Boxster Spyder.

The manually-operated hood is a lightweight item designed to keep the rain out and little more. When the hood is raised, the Spyder’s maximum speed is limited to 124mph to reduce aerodynamic loads on the fabric. The lightweight hood, together with the use of carbon-fibre for the seat frames, is claimed to save 21kg.

Aluminium doors save 15kg compared with steel items; the aluminium engine cover saves 3kg. Not unreasonably, air conditioning has been deleted from the specification, saving another 12kg.

Other weight-saving measures include a 10-litre drop in fuel-tank capacity, special wheels, a smaller battery, no radio, no cup-holders, and lightweight interior door trims. The Spyder’s interior is otherwise an adapted version of the Boxster S’s. Interestingly, the instrument cowl above the dials has been omitted, apparently to save weight. We assume Porsche has guarded against any unwanted head-up display in the windscreen at night.

Porsche claims that the changes carried out to the Boxster to create the new Spyder have cut seven seconds from the Boxster S’s lap time around the Nürburgring-Nordschleife.

The ride-height of the Spyder is 20mm lower than the standard car’s. This clearly lowers the centre of gravity and reduces the tendency to roll, which in turn allows better control of wheel geometry. Additionally, stiffer springs and dampers are used; the front track is increased by 4mm, the rear by 8mm. A mechanically locking differential is fitted as standard; locking values are 22 per cent. under power and 27 per cent. on overrun.

The Boxster Spyder is powered by a tuned version of the familiar 3.4-litre flat six. The unit is mounted ahead of the rear axle line, with a longitudinal crankshaft axis, and uses direct fuel injection. Maximum output is 320PS — 10PS more than in the Boxster S, but at a rather busy 7200rpm against the S’s 6400rpm peak. A six-speed manual gearbox is fitted as standard, but the Porsche-Doppel­kupplungs­getriebe (PDK) double-clutch transmission is available as an option. The automated unit, as is often the case, is actually a little more efficient than the conventional manual box — or, to be pedantic, the car is more efficient when it is being driven through the PDK transmission and controlled electronically.*

* The two statements are not the same. An automated gearbox can be slightly less mechanically efficient than a manual unit and yet still return superior overall efficiency in use if its control system is effective at getting the best from the engine and its gear-changing is not too demanding of hydraulic power.

The Spyder equipped with the PDK transmission returns an overall fuel consumption figure of 9.3l/100km or 30.4mpg, which is around four per cent. better than the 29.1mpg (9.7l/100km) the manual version delivers. (Note that we are converting from imperial reference figures to metric.)

Porsche Boxster
Spyder
Boxster S
Cylinders 6HO 6HO
Valves 4 4
Swept volume 3436cc 3436cc
Compression
ratio
TBA 12.5:1
PS/rpm 320/7200 310/6400
Nm/rpm 370/4750 360/4400
Maximum speed 166
124*
170
0-100km/h 5.1s
4.8s†
5.3s
5.0s†
Combined MPG (l/100km) 29.1 (9.7)
30.4 (9.3)†
29.7 (9.5)
30.1 (9.4)†
CO2 g/km 228
218†
223
221†
Transmission M6 (A6) M6 (A6)
Driven wheels Rear Rear
Fuel tank 54l 63l
Kerb mass (kg) 1275
1300†
1355
1380†
* Hood raised
† With automated twin-clutch PDK transmission

Heritage

Porsche sees the Boxster family as being heirs to the 550 Spyder of 1953. This was Porsche’s original mid-engined roadster, designed with low weight and agility in mind. Unlike the current Spyder, its fifties progenitor was built for motorsport.

The Spyder (also known as the RS) featured all-independent suspension with torsion-bar springing. Double wishbones controlled the front wheels, with swing axles at the rear. Kerb weight was a modest 550kg. (The model designation is not derived from this, but rather from the production number 550 given to the project by the Porsche Engineering office. The numbering system began in 1931.)

Porsche 550 Spyder.

The power unit featured in the 550 Spyder is known as the ‘Fuhrmann engine’. The first drawings of this new all-alloy 1.5-litre flat four, developed under the guidance of Porsche Senior Engineer Ernst Fuhrmann, were completed in 1952.

Technical features such as four overhead camshafts with side shaft drive, double ignition, a crankshaft running in four bearings and eight-litre dry sump lubrication gave the engine a reliable maximum output of 110PS at 7800rpm. In later years, maximum power reached 180PS.

In 1956, a new Spyder was introduced. The 550A used a lighter and much stiffer tubular spaceframe instead of a flat chassis. Engine output was 135PS, and kerb weight was 530kg.

Porsche-Doppelkupplungsgetriebe (twin-clutch gearbox).
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