TVR Cerbera Speed 12

Making it world debut at the London Motor Show was the Cerbera Speed 12. It's a departure from TVR's usual manufacturing methods. It's got a hybrid aluminium honeycomb and tubular steel chassis. Carbon fibre bodywork sits atop the chassis. The whole body is reportedly only 40kg.

Up front sits an 800bhp V12 engine. Although originating from two Speed 6 engines bolted together, the V12 has been well developed since.

TVR claim that the GT2 is in the tradition of weekend race cars that can be driven to and from the track. With TVR now serious about contending a GT series next year, they will have to produce road going cars for homologation purposes. Expected to retail in excess of Ł150,000 you'll need to convince TVR that you're pretty serious about a purchase before they'll let you near this beast.

Construction

International GT rules mandate a flat floor and a tubular steel roll cage and so the primary chassis of the car consists of a T45 steel tubular safety cell which is integrally braced by the flat aluminium honeycomb floor and bulkheads.

This hybrid construction both follows the racing rules and allows for the car to be quite simple to assemble. The front bulkhead is immediately behind the engine whilst the rear one lies directly ahead of the rear wheels. This allows the exhausts to exit cleanly away from the engine and then turn ahead of the footwell to run down the sills, and the driver to sit as far rearward as possible.

The removal of the previous structural reliance upon the tunnel allows this to be as narrow as the gearbox dictates and in turn allows the driver to be positioned further inboard towards the centreline of the car. The honeycomb floor and bulkheads are stiff enough to accept the seat mounts and pedal assemblies directly without need for further reinforcement.

Side Impact Safety

The floors are stabilised at their outer edges where they are folded up 90° to give 40mm of crushable protection for the occupants. The wide sills house the silencers which are also contribute to the side impact protection which ends finally with the cage doorbars. Because the floor and bulkhead assembly form the complete cockpit area they can be assembled, bonded and riveted before the cage is bolted into place. This then forms a sealed centre section that contains the driver and fuel tank safely within the rollover cage and also has the required flat floor.

There are front and rear subframes that are simple, light yet stiff tubular fabrications (again in T45 steel). These are bolted to the cage through the honeycomb bulkhead panels via ingenious self aligning steel fittings that make use of the shear stiffness of the bulkheads to triangulate the roll cage structure.

Engine Fitment

The engine is fitted by removing the entire front end of the car, without the necessity of disconnecting any oil or water pipes. The outermost ends of the subframes terminate in aerospace alloy billet bulkheads that fulfil both structural and practical roles.

At the front two bulkheads back to back, machined from solid plates, form a void that is the oil dry sump tank; provide all the mountings for the front suspension and steering rack and physically connect the open subframe tubes.

At the rear a similar bulkhead machined from solid plate seals the rear of the differential housing and provides mountings for the rear suspension. The differential housing provides a structural load path between the rear subframe and the cabin section via a fabricated casing that also locates the rear lower wishbones.

Suspension

The suspension consists of classic double wishbones all round, with coil over gas dampers operated by pushrods and with rising rate anti-roll bars front and rear. The centre lock magnesium wheels run on steel hubs within exquisitely fabricated aerospace steel vaned uprights to allow cooling air to reach the massive (15") brake discs and calipers. At the rear the driveshaft CV joints are integrated within the hub/bearing assembly. All of the suspension joints pivot on spherical bearings.

Bodywork

The bodywork is all manufactured in house out of carbon fibre pre-preg composite with a mixture of Nomex and Kevlar reinforcement, the overall style being that of a "Cerbera on steroids"!

The entire front and rear are one piece mouldings for quick and easy access whilst the cabin section is bonded to the honeycomb bulkheads and sides to form the sealed passenger compartment.

Particular attention has been paid to the air flow with the intention of minimising under bonnet turbulence and cooling, both for the engine and brakes and also for the driver.

The front screen contains a heating element for elegant demisting whilst rear vision is perhaps described at best as "adequate", given the imposing presence of the rear wing.