Prepared in cooperation with rally specialist Richard Tuthill, a dominant name in grueling rally events such as the East African Safari Classic and Dakar Rally, the All-terrain Competition Study or ACS enables this air-cooled 911 to compete in off-road racing. And to highlight the broad capabilities of the ACS, two machines were commissioned—one focused on high-speed desert rallying, and another for high-speed tarmac events.

Things start with a 1990 Type 964 Porsche 911. Singer and Tuthill then strengthened the monocoque for heavy off-road use. The body panels were then switched to carbon fiber for quick replacement and underbody access.

From there, a specialized long-travel suspension with twin, five-way adjustable dampers per corner were installed along with forged 8x16” wheels with BF Goodrich All-Terrain tires, and 4-piston monobloc disc brakes with a hydraulic handbrake.

Giving it more oomph, a 6.0-liter air cooled twin turbocharged flat-6 was installed. Developing 450 horsepower and 569 Nm of torque, the ACS uses a 5-speed sequential gearbox. Power is routed through a permanent all-wheel drive system with front, center, and rear mechanical limited slip differentials.

Built for the likes of the Baja 1,000 and Dakar Rally in mind, it also comes with a long-range fuel tank, two full-sized spare race wheels and tires in the front trunk and rear storage area, full FIA specification roll cage and sport seats, a rehydration system, and a GPS race navigation system. 

As always, each car is approached as a bespoke restoration, and Singer is only able to price them once a client approaches them for their restoration services. 

The ACS restoration has been undertaken as a collaboration between the two companies. Singer’s Design Office in California has led a joint engineering team with assembly undertaken in the UK at the Tuthill facility in Oxfordshire. Future cars will all be modified at Tuthill’s facilities.