The liquid-cooled engine in Porsche’s new 911 GT3 RS makes 513bhp and revs to 9000rpm. How the hell does this old air-cooled flat-six all but match it? Witchcraft! By Ben Miller
IT CAN’T HAVE figured much in Porsche’s thinking: that when it went liquid-cooled with the 996-generation 911’s flat-six, the goal would be left wide open for the air-cooled engine’s ongoing evolution. Porsche had no choice but to move on, and did so convincingly. But great engines refuse to die, and in the hands of Californian restoration specialist Singer Vehicle Design, the air-cooled 911 engine has undergone an aston- ishing evolutionary leap.
Thanks to its obsessive but sympathetic perfectionism, Singer’s now a global brand, with 100 rebuilt cars to its name. But the 964 911 you see here, a result of Singer’s Dynamic Lightweight Study (DLS), takes its work to an- other level. ‘Standard’ Singer projects cost around $600k; each DLS-inspired restoration will cost at least $1.8 million.
According to Singer main man Rob Dickin- son, a musician and Porsche nut, the DLS’s ele- vator pitch was simple: ‘What would an old 911 look like if we did it with an F1 team?’
The F1 team Singer chose was Williams, and more specifically its Advanced Engineering arm. The brief? ‘To develop the most advanced air-cooled engine yet,’ explains Dickinson.
‘The objective was 500bhp from 4.0 litres. The cases would remain 964 911 but beyond that this engine would receive the best solutions money can buy, including four-valve heads. In the words of one of our clients, we’ve bestowed upon an icon the gifts of the modern age and noble material science. It’s a bit nutty but we had faith in the notion that if we could execute it well then, despite the unnerving price we’d have to charge, people would appreciate it.’
If this outrageous engine has a father it’s Williams Advanced Engineering’s John Magee. ‘The crankcases are 964 – the flat-six engine is such a sound design fundamentally that it’s strong enough for these kind of high-performance applications, as Porsche proved with its own turbocharged derivatives,’ says Magee. ‘Four-valve heads were the only way to go – you can take a two-valve engine a long way, with bigger valves for better gasflow, but the reciprocating masses in the valvetrain become a problem; you can’t achieve the engine speeds you need.
‘The four-valve heads were designed unique- ly for this application. We’ve adopted a finger-follower valve actuation system, which gives us both the lightweight valvetrain we needed for high revs and the flow area we wanted for good power.’
Further cutting-edge performance engi- neering details include low-friction coatings (a diamond-like coating on the finger followers and piston pins, for example, and chrome-ni- tride on the valves), extensive use of light- weight materials (the valves are titanium, as are the con-rods) and a completely re-designed lubrication/oil-cooling system.
‘We’re very proud of the engine; it sounds like nothing else,’ says Singer Vehicle Design’s Rob Dickinson. ‘It almost sounds like an F1 engine.’ With good reason.