Sports Racing Cars - Types of Cars - Sports Prototype

Sports Prototype

Sports prototype is the name given to a type of car used in sports car racing and is effectively the next automotive design and technological step up from road-going supercars and are, along with open-wheel cars, the pinnacle of racing-car design.

The highest level in sports car racing these cars are purpose-built racing cars with enclosed wheels, and either open or closed cockpits. Since the World Sportscar Championship was conceived there have been various regulations regarding bodywork, engine style and size, tyres and aerodynamics to which these cars must be built. Sports-prototypes may be (and often are) one-of-a-kind machines, and need bear no relation to any road-going vehicle, although during the 1990s some manufacturers exploited a loophole in the FIA and ACO rules which meant cars racing in the GT category were actually true sports-prototypes and sired some road-going versions for homologation purposes. The Dauer-Porsche 962LM, Porsche 911 GT1-98, Mercedes CLK-GTR and Toyota GT-One were prime examples of prototypes masquerading as GTs.

In simplistic terms, sports-prototypes are two-seat racing cars with bodywork covering their wheels, and are as technically advanced and, depending on the regulations they are built to, as quick as or quicker than their single-seat counterparts. Although not widely known, sports-prototypes (along with Formula 1 cars) are responsible for introducing the most numbers of new technologies and ideas to motorsport, including rear-wings, ground effect 'venturi' tunnels, fan-assisted aerodynamics and dual-shift gearboxes. Some of these technologies eventually filter down to road cars.

In the ACO regulations, two categories of sports-prototypes are now recognized: P1 and P2. Cars competing in the P1 category must weigh no less than 900 kg and are limited to 6000 cc naturally aspirated and 4000 cc turbocharged engines. 5500 cc turbo-Diesel engines are also permitted in P1 – Audi scored Le Mans victories with such a car in 2006, 2007 and 2008 and Peugeot returned to racing in 2007 with a car with a similar powerplant (Peugeot 908). P2 cars can weigh much less — first 675 kg, then 750 kg and now 825 kg — but are restricted to 3400 cc V6 or V8 normally aspirated or 2000 cc turbocharged powerplants. In the European series in which endurance is a priority and P2s have been run largely by privateers, P2s have not challenged P1s for outright victories; in the American Le Mans Series with generally shorter races P2 has become the most active prototype category with serious involvement from Porsche and Acura and whereas P2 in Europe tends to involve races of attrition, in the US series the P2s, particularly the Porsche RS Spyder are often quicker round a lap than P1s, with the Porsche having scored many overall victories against the Audis in P1.

Prototype rules for 2010 and beyond will encourage production-based engines (GT1 engines in LMP1, GT2 engines in LMP2) and rules to equalise the performance of petrol and diesel LMP1s are also being addressed.

Daytona Prototypes are a product of the Grand-Am Rolex Sports Car Series, and offer a different interpretation of the prototype theme. DPs, as they are often called, are closed-cockpit, purpose-built racing machines which are less expensive and (deliberately) somewhat slower than Le Mans Prototypes, which were becoming dangerously quick on the Daytona oval and prohibitively expensive for smaller teams to run. Compared to the LMPs, DPs are severely limited in terms of approved technology; for instance, they are required to be constructed of steel tube frames with carbon-fiber skins, rather than being carbon-fiber monocoques, and must use production-based engines. The intention of the DP formula was to provide a class in which tight technical regulations encouraged close competition and where budget would be relatively unimportant. DP chassis are subject to a franchise-like approval system in which only approved constructors are eligible, with rules stability enforced for several years at a time, although this led in 2007 to established constructors like Lola and Dallara entering the 2008 series by taking over the rights of existing constructors (Multimatic and Doran respectively).