Last year, Porsche restomod and reimagining company Singer revealed its 420-horsepower, 8,500 rpm, 4.0-liter flat-six with its own special four-valve cylinder head. Now the company is showing off more of that new engine, revealing some of its tricks along with the help it got from the engine experts at Cosworth.
Deep Inside An Immaculate Flat-Six
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Singer sent racing driver Marino Franchitti (Dario’s brother) to the Cosworth engine building facility for a look inside. Cosworth has been building high-performance engines for racing, for road cars, and even for the US Navy, since 1958. Its engines have won 176 races in Formula 1 and loads of IndyCar events, and were behind the V12 engines used in the Aston Valkyrie and GMA T.50, as well as Bugatti’s new V16.
So who better to take the vintage Porsche flat-six and transform it into a modern monster? It’s a step back to the company’s roots, after all, of starting with an existing engine and making it better. For this project, Cosworth starts with the engine from the Porsche donor car rather than a brand-new casting. The engine is completely cleaned, inspected, and re-machined to modern fitment and dimensions, leading to the new 4.0-liter displacement.
Because the oil-cooled factory cylinder heads were never intended to pump out more than 400 horses, Cosworth’s own four-valve heads change oil for water. The cylinder barrels, though, are still air-cooled with big fins and new under-piston oil squirters.
The new heads add variable valve timing, and Marino says he can’t wait to experience the torque curve that results from the changes. It’s a smooth curve, instead of the jagged one of the old air-cooled mill. Smoothing out the power delivery is always a good thing, but in an old 911 that loves to step out of line, it can be extremely important. Especially if you’re accelerating in a corner.
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A glorious set of carbon fiber intake plenums mixed with alloy to hold the fuel injectors sits on top of the engine. Bruce Wood, Cosworth’s technical director, said that this was the hardest and most important part to develop.
Nothing Sounds Like A Porsche Flat-Six
Franchitti and Wood spend half an hour in the above video showing us inside the engine crankcase, the cylinder heads, and all the other parts that go into this very special flat-six. To go from Singer saying “we want an engine” to the first engines on the dyno took just nine months, Wood said. Then we get to see – and more importantly hear – the engine on the dynamometer, as it spins the load cell to that 420-hp max output.
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The final bit of development is tuning the fuel injection, timing, and spark. Cosworth monitors temperatures on every cylinder, making sure that exhaust temperatures match across the engine, which shows that each cylinder is running optimally. Big temperature differences mean a cylinder isn’t performing quite right.
It ends with some bad news for buyers, though. This engine doesn’t make 420 hp according to the dyno. We don’t think the owner will mind, though, since the six makes 450 hp instead. Oh, and it sounds like heaven at 8,000 rpm, even if they didn’t push it all the way to the 8,500 rpm redline.
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All the 100 coupes in this run have been spoken for. Singer says there is still some availability if you want one of the 75 convertibles.
Source: Singer
