Theon Design reveals supercharged flat-six for new Porsche 911 restomod

Founded in 2016 by automotive designer, Adam Hawley, Theon Design specialises in producing reimagined 964s. Each car takes eighteen months to build, is entirely bespoke and is a collaboration between the car’s owner and Hawley’s team, which strives to achieve exacting specification using the best materials and superior quality workmanship.

For the brand’s next build, a supercharged 3.6-litre air-cooled flat-six takes centre stage. Featuring a Rotrex blower and a water-methanol injection system, the rebuilt and modified boxer should see a stable 450bhp and 369lbft torque, offering real-world tractability and spellbinding top performance with a pleasingly linear power curve. Theon Design already offers customers a choice of three ultra-responsive, high-performance naturally aspirated engine configurations (a 285bhp 3.6-litre flat-six, a 370bhp 3.8-litre unit or the option of a 400bhp four-litre variant), but this supercharged version is the company’s first foray into forced induction. “We wanted to deliver additional performance, but also maintain the seamless delivery of a Porsche naturally aspirated engine,” Hawley told us. “This is why we opted for a Rotrex centrifugal supercharger, providing linear power delivery and instant throttle response without the delay or lag associated with turbocharged air-cooled flat-sixes. We’re very pleased with the results. The supercharger has a subtle ‘whine’, but the bark of the flat-six stays front and centre, with wonderful added character.”

The supercharger chosen by Hawley offers excellent integration and compatibility with the Porsche flat-six, advantages Theon Design has further leveraged through its OEM+ philosophy. “As every Porsche enthusiast knows, there’s not a great deal of room within a 964 engine bay, which is why we located the supercharger in the space previously occupied by the factory airconditioning unit,” Hawley explains.

A highly focused six months was spent developing the optimum installation solution. The supercharger had to maintain the host engine’s character and Porsche’s original engineering values. To achieve this, the team utilised some of the existing air-con bracketry to support the Rotrex hardware, developing and designing additional mounts to mirror the design and materials used for the cam covers and other elements. Significant effort was undertaken to ensure this would provide solid and durable support for the supercharger, allowing for zero movement or flex, no matter how extreme the driving conditions. To maintain a clean look in the engine bay, Hawley decided to introduce a watermethanol injection system to proceedings, negating the need for an intercooler and air intake apertures in the bodywork. “Injecting a watermethanol mix into the plenum not only provides the same cooling function as an intercooler, but also increases octane rating of the fuel, boosting 98 octane to 110 and improving performance as a result,” he says. The methanol supply system is fully integrated, with a 3D carbon-printed section to bridge the plenums, complementing a carbonfibre engine and fan shroud. We’ll bring you more detail when build of the car is complete.

HAWLEY DECIDED TO INTRODUCE A WATER-METHANOL INJECTION SYSTEM TO PROCEEDINGS