Even though it’s substantially new, a casual observer isn’t going to mistake this car for anything other than a Porsche 911. Its shape is now so easily recognisable that it has become an icon.
However, in its latest iteration Germany’s most famous automotive export has grown by 56mm in overall length, 100mm in wheelbase and 46mm at the front track over its predecessor.
If you understand basic physics, you need know very little of this Porsche’s dynamic backstory to work out why. With a longitudinal engine and gearbox hung out behind its rear wheels, the 911 has always been fundamentally inclined towards two idiosyncratic behavioural problems: power understeer and body pitch. For lever, fulcrum and load, think body, rear axle and engine. With more space between both the axles and the individual front wheels, both key dynamic challenges have been addressed here.
Aluminium has been used in place of steel throughout a great deal of the new 911’s construction. On the ‘991’, almost all of the exterior body panels are aluminium and most of the body-in-white, except in areas such as the car’s pillars, where high compression strength is required.
As a result, on the coupé there’s like-for-like weight saving of around 45kg over its predecessor (depending on which model you are driving and what extras and are fitted), and a 20 per cent improvement in torsional rigidity.
The cabriolet is a few millimetres lower than than the coupé, but it’s so fractionally different to be almost inconsequential. Porsche also claims a similar weight saving over its drop-top predecessor of 45kg, although its actual kerbweight is inevitably higher (around 50kg) as a result of all the associated strengthening. The torsional rigidity of the drop-top is said by Porsche to have improved by 18 per cent over that of its predecessor.
In design terms, the main head-turning feature of the cabriolet is the all-new ‘panel bow top’ roof, the frame of which is constructed from fabric and composite plastic and sits on a frame made of magnesium and aluminium.
This new roof has several packaging benefits, not least that Porsche has been able the follow the profile of the coupé’s roofline more closely than it could with the old-style multi-layered fabric structure. It drops in 13 seconds.