Opinion: does the flat six engine have a future in the 911?
At the 2010 Geneva Motor Show Alois Ruf exhibited his latest creation; a V8-engined 997. Now, putting V8s in 911s is nothing new; US hot-rodders have long been guilty.
However, in 1991 Porsche itself toyed with the idea of V8 power for the 993; a development car was fitted with an Audi V8 and, apparently, no one who drove the car ever realised that a water-cooled eight had replaced the air-cooled six, hard as it is to believe.
In the end, of course, Porsche stuck with the 3.6-litre flat six, lightening its innards and quietly working on the new water-cooled generation of engines which would retain the essential flat six architecture that defines the 911. The next 911 will harbour an evolution of this engine.
The Ruf interpretation is nevertheless extremely interesting. The inveterate Porsche improver has been working away at this project for several years and the result is a beautifully compact 90-degree angle V8 said to weigh 40kg less than the 997’s flat six, once all the ancillaries are fitted.
More surprising, though, is Ruf’s counterintuitive claim that its centre of gravity is lower than that of the current A91 flat six. The two extra cylinders are said to elevate performance to another level.
The 997 chassis accepts this V8 engine with surprisingly little modification, we’re told – the only intervention being some cutting of sheet metal around the bulkhead.
Ruf’s innovations matter because so often they have anticipated the route Porsche would eventually take. One of the first to tune the 930, Alois Ruf used twin turbochargers when Porsche still relied on a single turbocharger (and the archaic K Jetronic fuel injection).
Ruf’s 911 Turbo ‘Yellow bird’ which clocked 211mph in 1987 gave him world renown. He devised a five-speed gearbox when Porsche still made the 930 do with a four and when Porsche upgraded to a Getrag five-speed, Ruf riposted with his own six-speed. He also offered a Fichtel & Sachs-based six-speed clutchless change a decade before Porsche launched PDK.
Over the decades, Zuffenhausen has usually been content to let Porsche tuners get on with it; they produce only a tiny quantity of cars, mostly in a far higher price bracket. Ruf, however, which is a manufacturer in its own right, enjoys a rather closer relationship with Porsche. Indeed one of the éminences grises behind the Ruf V8 is Reinhard Könneker, a former colleague of Hans Mezger at Porsche.
For years, since the 2.4 engine was bored out to 2.7, there have been mutterings that the flat six had reached the end of its development potential. Yet Porsche always managed to pull rabbits out of hats, taking the air-cooled block to 3.8 litres before starting again with the water-cooled engine and at the same time meeting ever stricter emissions rules.
However the temptation of a V8 for the 911 in the longer term has never been greater, especially given continuous pressure from VW to reduce development costs and share platforms.
Wolfsburg will undoubtedly point to the Ruf example as a neat engineering solution. However, a school of thought (and not just the purist) holds that without the flat six the 911 would finally lose what makes it special. For many its equipment level is already too high and the driving experience over-refined; a V8 as made by every Tom, Dick and Enzo would be the last straw. Even if it’s not imminent, that flat-six growl is something the 911 could ill afford to lose.