Category | 1971:Group 6 Prototype-Sports Car 1972-73:Group 5 Sports Car |
---|---|
Constructor | Scuderia Ferrari |
Designer(s) | Mauro Forghieri |
Technical specifications | |
Chassis | Aluminium central monocoque with steel spaceframe front and rear |
Suspension (front) | Double wishbone, outboard coil spring/damper |
Suspension (rear) | Single top-link, reversed lower wishbone, twin radius arms, outboard spring/damper |
Engine | Ferrari 2,991 cc DOHC flat-12, naturally aspirated, mid-mounted |
Transmission | Ferrari 5-speed manual |
Fuel | Shell |
Tyres | Firestone/Goodyear |
Competition history | |
Notable entrants | Scuderia Ferrari |
Notable drivers | |
Debut | 1971 1000 km Buenos Aires |
Constructors' Championships | 1 (1972 WSC) |
The Ferrari 312 PB was a Group 6 Prototype-Sports Car introduced in 1971 by Italian carmaker Ferrari. It was officially designated the 312 P, but often known as the 312 PB to avoid confusion with a previous car of the same name. It was part of the Ferrari P series of Prototype-Sports Cars but was redesignated as a Group 5 Sports Car for 1972.
In 1970, a change in the regulations for sportscar racing for 1972 was announced. The loophole for the big 5-litre sports cars (such as the Porsche 917 and Ferrari 512) was closed, and the minimum weight of the 3-litre prototypes was raised to 650 kg (1,433 lb).
Porsche considered this too heavy as their Porsche 908/03 were 100 kg (220 lb) lighter, and this advantage would have been lost. On the other hand, their air-cooled two-valve engine was low on power with 370 hp (276 kW), and the development of a new engine would have been necessary. Thus, Porsche did not enter world championship sports car races after 1971 and sold the 908s to customers who would have to add weight to them. Matra and Alfa Romeo were willing and able to compete, but only in selected seasons or events. Also, Ford's successful Formula 1 Cosworth-V8 engine was available for independent chassis builders, but vibrations made it unreliable for endurance racing.
After having been beaten by the Porsche 917 in 1970, Ferrari abandoned further development of the Ferrari 512M, leaving the 512 to customer teams like Penske Racing, which had some success with their improved 512M in 1971, though. Penske, probably not very happy about the lack of support from the factory, joined Porsche for their Can-Am effort with the turbocharged Porsche 917/10.
Instead, in 1971, Ferrari focused on a new 3.0L prototype based on the 180° flat-12 boxer from the 312B F1 car. Officially this design was known as 312P, the motorsports press appending the B to avoid confusion with the earlier 312P V12 cars. This design was similar to the traditional Porsche engine layout with its low center of gravity, but Ferrari used water-cooling and 4-valve heads. The car was promising, but did not win, while the similar Alfa Romeo 33 scored two wins against Porsche's dominance. Whereas the engine bears many similarities in design to the F1 engine, in practice, nearly every part is different and non-interchangeable with the F1 flat 12. This has led to problems for users of these cars in historic racing, as spare parts for these quite fragile engines, are, in comparison to the F1 flat 12 engine, very difficult to obtain.