Ferrari Berlinetta Boxer
The Ferrari Berlinetta Boxer is a series of sports cars produced by Ferrari in Italy between 1973 and 1984. The BB was designed by Leonardo Fioravanti at Pininfarina. The first BB model, the 365 GT4 BB, replaced the front engined Daytona and was the first in a series of road-going Ferraris equipped with a mid-mounted flat-twelve engine. The 365 GT4 BB was succeeded in 1976 by the BB 512, equipped with a larger displacement engine, then by the fuel-injected BB 512i in 1981. The series was discontinued in 1984 when the BB 512i was replaced by the Testarossa, which used a revised version of the flat-twelve engine.
Background
Production of the BB was a major step for Enzo Ferrari. He felt that a mid-engined road car would be too difficult for his buyers to handle, and it took many years for his engineers to convince him to adopt the layout. This attitude began to change as the marque lost its racing dominance in the late 1950s to mid-engined competitors. As a result, the rear-mid-engined 246 P Formula 1 car was introduced in 1960, followed by the Dino SP racing sports prototypes in 1961. In 1963, the company also moved its V12 engines to the rear with its P and LM racing cars.Introduced in 1967, the Dino 206 GT and 246 GT/GTS road cars were the first road-going Ferraris to use the rear-mid-engined layout, albeit under the lower-cost Dino marque. Ferrari's flagship V12-powered road cars remained front-engined through the early 1970s, with the 365 GTB/4 Daytona and 365 GTC/4 introduced in 1968 and 1971, respectively. In 1973, Ferrari introduced the 365 GT4 Berlinetta Boxer as its first mid-engined 12-cylinder road car.
Ferrari first used the flat-12 engine layout in racing cars, starting with the 1964 512 F1. The 512 F1's 1.5 liter engine was designed by Mauro Forghieri, technical director of the racing department. This engine design was further developed in several Formula One and sports prototype racing cars, including the 1968 212 E, 1970-75 312B, and 1971 312PB. These racing engine designs became the basis for the road-going flat 12 engine introduced in the 365 GT4 BB.
Design and development
Following the introduction of the production 365 GTB/4 Daytona in 1969, Ferrari engineers led by Dr. Ing. Angelo Bellei began work on a successor, the 365 GT4 BB. Though it shared its numerical designation with the 365 GTB/4 Daytona, the 365 GT4 BB was radically different in layout than the front-engined 365 GTB/4. The new car was to have rear mid-mounted flat-12 engine, arranged longitudinally. While this configuration was unprecedented among Ferrari road cars, the design team drew upon the existing chassis design of the mid-engine 250 LM and Dino 206/246, as well as the flat-12 engines developed for the Scuderia Ferrari beginning in 1964. The first prototype 365 GT4 BB was unveiled at the 1971 Turin Motor Show. Prototypes were further refined by an extensive road and track testing program led by Ferrari test driver Giorgio Enrico. As Ferrari engineers already had considerable experience with both the layout and engine design, development work proceeded rapidly and only small changes were seen between the early prototypes and the first production 365 GT4 BB. The production 365 GT4 BB was first offered for sale in 1973.Engine and transmission
Dr. Ing. Giuliano de Angelis oversaw the development of the Tipo ''F102A engine used in the 365 GT4 BB. This engine was derived from both the Mauro Forghieri-designed Tipo 001 3.0-litre flat-12 engine used in the 1969 Ferrari 312B Formula One car and the roadgoing 365 GTB/4 engine. The total displacement of the new engine was 4390.35 cc with a bore of 81 mm and a stroke of 71 mm, dimensions which matched the 365 GTB/4 engine.While the "Berlinetta Boxer" name has been used by both Ferrari and the press to describe BB-series cars, this engine was not a true boxer engine. In the Tipo F102 A and its derivatives, each pair of opposing pistons share the same crank pin and move in the same direction during operation. In a boxer engine, pairs of opposing pistons move in opposite directions. On this point, Ferrari engine designer Mauro Forghieri stated "Please, don't call it boxer. Technically, it is correct to say that this engine is a flat-12, or has 12 cylinders with the heads at a vee angle of 180°."
The engine block was constructed of Silumin alloy, with cast iron cylinder liners. Pistons were light alloy and the crankshaft was forged steel. The cylinder head design was very similar to that of the 365 GTB/4, incorporating dual overhead camshafts and two valves per cylinder. The four camshafts were driven by two timing belts, which reduced noise and weight compared to the timing chains used on earlier 12 cylinder Ferrari engines. Air and fuel were supplied via four 3-bbl Weber 40 IF 3C carburetors. The ignition system consisted of a single Magneti Marelli distributor and two coils. The engine was lubricated by a wet sump, which was replaced by a dry sump in the BB512 to avoid oil starvation issues. According to de Angelis and Bellei, the first prototype F102 A engine produced 380 bhp at 7,100 rpm and propelled the prototype to during testing. Ferrari brochures reported the production version of the F102 A engine produced 360 bhp at 7,500 rpm and 311 ft/lb of torque at 4,500 rpm, although figures reported in other factory and press publications vary.
The 365 GT4 BB was equipped with a five-speed manual transaxle and limited-slip differential. The transmission and differential were placed directly underneath the engine, alongside the oil sump. The Fichtel & Sachs single-plate dry clutch was located at the rear of the engine. Power reached the transmission via a set of drop gears and a horizontal shaft. While this layout increased the vertical height of the engine and transmission assembly and raised the car's center of gravity, it shortened the overall length of the assembly. This was advantageous for packaging reasons, as a compact engine/transmission meant the chassis could have a short overall wheelbase as well as a comfortable, spacious cabin.
The engine design of the Tipo'' F102 A continued to be developed by Ferrari after the introduction of the 365 GT4 BB. It led to the creation of a family of road-going Ferrari flat-12 engines, including the F102 B, F110 A and the engines of the Testarossa, 512TR and F512M. These later engines had an overall displacement of 5 liters.
Styling
The body of the 365 GT4 BB was styled at Pininfarina, supervised by Leonardo Fioravanti. The design was influenced by the Ferrari P6 Berlinetta Speciale, a one-off concept car created by Pininfarina in 1968. The first 365 GT4 BB prototype was presented to the public at the 1971 Turin Auto Show. It had a low, wedge shaped nose with hidden headlamps, a steeply raked windscreen and a wide rear section truncated by a vertical tail. The design was refined using wind tunnel testing at Pininfarina's facility. As a result of these aerodynamic studies, a spoiler was placed behind and above the passenger compartment, spanning the two buttresses or sail panels on either side of the engine cover. This spoiler was intended to reduce drag, improve stability and direct air into the intakes on the top of the engine cover.The central section of the bodywork was constructed of steel, while the front and rear covers and door were constructed of aluminum alloy. The front and rear lower valences/bumpers were fiberglass. The front and rear covers are a clamshell design, with hinges allowing the front cover to pivot forward and the rear engine cover to pivot rearward. This allowed easier maintenance access to the engine and use of the small front luggage compartment.
The 1971 prototype's paint scheme was designed to lower and reduce the visual mass of the car when seen in profile. To this effect, the bodywork was split with a horizontal seam near the top of the wheel rims and everything below this point was painted satin black, including both front and rear bumpers. This two-tone paint scheme would carry over into production BB models. Ferrari later offered the two-tone paint scheme as an option on other models such as the 308, where it was commonly referred to as "Boxer" paint.
The bodywork of the 1971 Turin Auto Show prototype closely represented that of the production 365 GT4 BB, with some small differences. The prototype had four tail lamps, while the production 365 GT4 BB had six. The prototype's fuel filler was placed below the rear quarter window, but this was relocated to a buttress/sail panel in the production version. This design was carried over with only minor changes through the final model of the series, the BB 512i.
Chassis and suspension
The 365 GT4 BB chassis was constructed of steel tubing, as was standard Ferrari practice at the time. According to lead engineer Dr. Ing. Angelo Bellei, the chassis design was directly influenced by the chassis of the 250 LM and the Dino 206/246. While the central bodywork formed a semi-monocoque with the steel chassis, the front and rear bodywork was unstressed and only supported by light subframes. The front bodywork and subframe was designed to deform and absorb energy during a crash. Crash safety was also improved by the presence of two large diameter tubes which ran diagonally from the engine cradle to the roof, providing extra strength during a rollover crash.All four wheels had double wishbone independent suspension, with a single coil spring and shock absorber for each front wheel and a pair for each rear wheel. Dual anti-roll bars, non-powered rack and pinion steering and four wheel disc brakes were also equipped. The 365 GT4 BB was fitted with Michelin XWX tires, with front and rear tires both sized 215 70 VR 15. Later models would use a staggered configuration with wider rear tires.
Production history
365 GT4 BB
The production version of the 365 GT4 BB was introduced at the 1973 Paris Motor Show. The start of production coincided with the 1973 oil crisis, and as a result initial demand was low. Ferrari initially planned a limited production run of only 25 cars. Production began slowly, with only two dozen cars constructed during the first year of production. Demand gradually increased and later cars were produced at the rate of one per day. In total, 387 examples were built between 1973 and 1976, making it the rarest of all Berlinetta Boxer models. 88 were right-hand drive, with 58 of these intended for the UK market. Production 365 GT4 BB bodywork was constructed by Scaglietti and final assembly took place at Ferrari's factory in Maranello.Factory list price in 1973 was 18,290,000 Lire. By 1976, the price increased to 24,375,000 L., approximately US$30,000. List price in the UK was in 1975. Air conditioning was optional, but most buyers selected it. Buyers could choose the two-tone "Boxer" paint with a black lower half, or conventional single color paint.
Contemporary press reception to the 365 GT4 BB was positive and journalists praised the car's handling and straight line performance. Road & Track tested a 365 GT4 BB in June 1975. The clutch in their test car slipped, but they still measured 0-60 mph in 7.2 seconds, 0-100 mph in 14.8 seconds and a standing quarter mile time of 15.5 seconds. R&T testers reached a top speed of 175 mph, making the 365 GT4 BB the fastest road car tested at the time. A later test of a fully functional car in the November 1976 issue of Car and Driver recorded 0-60 mph in 6.1 seconds and 0-100 mph in 14.1 seconds.