Bizzarrini GT 5300

Production period:	1964 to 1968
Class:	sports car
Body versions:	Coupe
Engines:	Gasoline :5.3 liters (268-309 kW)
Length:	4460 mm
Width:	1760 mm
Height:	1106-1110 mm
Wheelbase:	2450 mm
Curb weight:	1150 kg

The Bizzarrini GT 5300 was a low-volume sports car produced by the Italian automaker Automobili Bizzarrini in the 1960s.

History

The general design of the car is on the whole traditional; it is only inthe attention given to details and in the interpretation of the theme that the true characteristics Of the model may be observed. It has monocoque aluminium body, the parts of which are riveted on to a frame in a blend of
ressed steel and aluminium. The indepedent front suspension is by wishbones and the rear suspension has a De Dion rigid axle with longitudinal
thrust link-rods and is completed by a transversal Watt's linkage.The means of propulsion are at the front, but set well back with respect to the front track so as to bring the greater part of the weight back towards the centre of the car.

The bodywork which is designed by Bertone very aggressive in the general impression it makes. but with sleek, rounded lines that are carried well out horizontally. The shape is clearly and necessarily determined by aerodynamic demands but the result has the customary lightness that Bertone is so good at achieving. The GT Strada 5300, which in the past was better known by the name of Grifo A3C, is obviously a car designed for com- petitions and when it has been entered for various important international rallies and road races these have clearly brought out high qualities, par.
ticularly on fast, level roads.

Technically and historically, the Bizzarrini GT 5300 was related to the Milanese sports car maker Iso Rivalta’s Iso Grifo it was a  coupé with 2 doors and 2 seats with plastic and light alloy body. The vehicle, which was initially branded as the Iso A3 / C, was created as a racing adaptation of the Grifo. It became an independent model in 1965 after Bizzarrini and Iso Rivalta’s commercial links ended. The GT 5300 automobiles were provided by Bizzarrini in both a road-legal variant and a modified, motor sport-ready version. Both variants' production volumes fell short of Bizzarrini's projections. Even in motorsport, the GT 5300 was unable to capitalise on the victories that the essentially identical Iso A3 / C had earned in 1964 and 1965.

Giotto Bizzarrini, owner of the Tuscan company Automobili Bizzarrini since 1962, had already commissioned the chassis for the Iso Rivolta 300 in 1962. A year later Bizzarrini also designed the chassis for Iso's second model, which was designed as a sporty two-seater in the Gran Turismo style. Like the 300, this vehicle was supposed to connect a Corvette engine to a body designed by Giorgio Giugiaro for Bertone. It was initially named Iso A3 / L, with the L for Lusso (Luxury) stood and signalled that it was at the same time a sporty vehicle for a comfortable vehicle for road traffic. This Iso A3 / L later became world famous as Iso Grifo. Long before the series production of the Iso Grifo started in 1965, Giotto Bizzarrini derived from the A3 / L a competitive version that was suitable and intended to be used in racing. The initiative for this project came from Bizzarrini: He believed that the sale of the A3 / L road sports car could be significantly enhanced by racing successes. Renzo Rivolta supported the request, although he himself was sceptical of car racing.

The result of Bizzarrini's work was the Iso A3 / C (for Competizione). The A3 / C had an independent body, but had a similar to the A3 / L suspension and corresponded to this in the drive technology: here as there was a 5.3 -litre eight-cylinder engine from the Chevrolet Corvette used. The public saw the then unpainted car for the first time at the Turin Motor Show in October 1963. It was exhibited at the booth of Iso Rivolta, while the street version, the A3 / L "Grifo", was also presented at the Bertone booth, 

Half a year later, the A3 / L appeared for the first time at a racing event: Automobili Bizzarrini announced with the support of Iso Rivolta two vehicles designated as Iso for the 12 Hours of Sebring. Both vehicles failed with a technical defect. Over the next two years, there were several other races, including the 24 Hours of Le Mans, which were successful to varying degrees. From 1965, the A3 / C was produced in small series at Bizzarrini in Livorno; and initially sold through Iso Rivolta.

During the year 1965, there was a rift between Renzo Rivolta and Giotto Bizzarrini. Bizzarrini had provided some of the A3 / C vehicles with his brand emblem instead of the Iso Rivoltas; of greater importance, however, was the fact that Bizzarrini had the model name "Grifo" protected. Rivolta and Bizzarrini agreed to settle the dispute ultimately a division of market segments: Iso Rivolta was the brand name Grifo for exclusive use and limited itself in the future to produce the road sports car A3 / L under the name Iso Grifo and distribute, while Giotto Bizzarrini from late summer 1965, the sports version A3 / C under its own name as Bizzarrini GT 5300 produced. Bizzarrini also received chassis and driveline parts from Iso Rivolta, enough to build about 50 more vehicles. 

From the second half of 1965, Bizzarrini manufactured in Livorno in its own name a series of vehicles based on the A3 / C designed for Iso Rivolta. This resulted in different versions, which differed in terms of technology and structure: The roadworthy version was given the designation Bizzarrini GT Strada 5300. A racing version called Bizzarrini GT Corsa 5300, which was factory used in endurance racing. At customer's request Strada elements were also connected with those of the Corsa on some vehicles. With just three copies also a Spyder was created.

How many copies of the GT 5300 Bizzarrini produced after the separation of Iso in its own name, is also very unclear. The data in the literature and in other sources vary widely. Until the 1990s it was predominantly assumed that a total of 149 examples of the GT-5300 series were manufactured. For the years 1964 to 1966 a production of only 78 vehicles and believe that in the years 1967 and 1968 due to a focus on the successor Bizzarrini P 538 only a few more GT 5300 were built. Giotto Bizzarrini himself is not in a position to clearly define the scope of production. He claims to have had no exact accounting at the time because he was solely responsible for the technical side of the business. In addition, no consistent chassis numbers were used. 

The Bizzarrini GT 5300 is based - as well as the largely identical Iso A3 / C - on a semi monocoque of aluminium sheets. Structurally it resembled that of the Iso Grifo A3 / L, however, was wheelbase abbreviated form by 50 millimetres. The rear suspension with a rigid De-Dion axle on four trailing arms and a Watt linkage was the same as the Grifo A3 / L, the front with recirculating ball steering and individually on double wishbones suspended wheels was on its own. A special feature of the GT 5300 was the location of its engine: To store its weight as centrally as possible in the vehicle, Bizzarrini put him far behind the front axle. This meant that some parts - including the ignition distributor - were accessible only via the passenger compartment. They could be reached via a flap in the dashboard. The arrangement of the 140-liter tanks was as uniform as possible: one tank was located in the side sills below the doors, and a third, larger tank was installed behind the seats. Overall, Bizzarrini achieved a weight distribution in the ratio of 52 to 48  near to a distribution of weight: 50% front axle, and 50% rear axle. 

A Chevrolet engine of the type mounted regularly on the 1967 Corvettemodel has been adopted. This has eight cylinders arranged in a 900 Vee and with its engine capacity of 326.95 cu in, 5,358 cucm and its 10.25 compression ratio it produces 365 hp at 6,000 rpm; with a maximum torque of 377 1b ft (52 kgm) at 3,500 rpm. The dry weight of the car is 2,756 1b (1.250 kg) and it has therefore the very low power-weight ratio of only 7.5 lh/hp, 3.4 kg/hp. On all models Bizzarrini regularly used a 5.3-liter small-block eight-cylinder from GM, similar to the Chevrolet Corvette High Performance 340th Bizzarrini offered him in different processing and performance levels. The regular tuning measures included modified intake and exhaust ports as well as a modified crankshaft. The different models, however, got different carburettor systems. In the Strada usually a Carter, later a Holley four-carburettor was used, while the Corsa models over four double carburettors by Eduardo Weber (Type 42, later Type 45 DCOE) were supplied. In the Strada version, the engine reached about 365 bhp (272 kW), while for the Corsa models an output of about 400-405 hp (294-298 kW) was specified. At least one Bizzarrini GT was equipped for racing purposes with a 7.0-liter eight-cylinder engine from Ford, which is said to have delivered an output of 450 hp (331 kW), according to other sources even 550 hp (404 kW). This vehicle was later provided with a body of Neri e Bonacini and sold as Nebo 7 Litri.

PERFORMANCE

• Engine Capacity 326.70 cu in, 5,354 cc
• Fuel Consumption '4.9 m/imp 12.4 m/US gal, 19 x 100 km
• Max Speed 167.7 mph, 270 km/h
• max power (SAE): 365 hp at 6,000 rpm
• max torque (SAE): 377 1b ft, 52 kg m at 3,500 rpm
• max engine rpm: 6,200
• specific power: 68.2 hp/l
• speed in direct drive at 1,000 rpm: 27.2 mph, 43.8 km/h.
• max speeds: 66.5 mph, 107 km/h in 1st gear; 87.6 mph, 141 km/h in 2nd gear; 111.8 mph, 180 km/h in 3rd gear; 167.7 mph, 270 km/h in 4th gear; power-weight ratio: 7.5 lb/hp, 3.4 kg/hp

The body of the GT 5300 corresponded to that of the Iso A3 / C. It had almost no resemblance to the Iso Grifo A3 / L, which was designed as a comfortable Gran Turismo. The design of the sports car body is usually attributed to Giorgio Giugiaro and Bertone. Some sources, however, a clear majority of Giugiaro's influence on the design of the vehicle. After Giotto Bizzarrini had designed the body together with his employee Piero Vanni, while Giugiaro and Bertone had just made some refinements.

The body was purposeful in view of the desired sporting success. Even the Strada was extremely low with a height of only 1.11 meters; the sports model Corsa even reached only a height of 1.06 meters. The headlights were set back and covered with slices of polymethyl methacrylate (Plexiglas), the windshield was strongly curved. Bumpers were completely missing; some Strada models got for aesthetic reasons thin bumper imitations. The body is usually described as aerodynamically very efficient. Your drag coefficient should have been only 0.30.

As long as Bizzarrini completed the A3 / C models for Iso Rivolta, the body of the A3 / C was produced in Piero Drogo 's Carrozzeria Sports Cars plant in Modena. After Bizzarrini and Rivolta split up, the relationship with Drogo collapsed. The aluminium bodies for the GT-5300 models were then purchased from various suppliers. From September 1965 she came to the little Modenese body shop BBM, 1966 and 1967 at Grosso e Vece in Turin and after their bankruptcy finally Subalpina (1968).  Individual plastic bodies were also built by the boat manufacturer Vincenzo Catarsi.The completion of the cars took over in 1966 the special operation Carbondio in Turin.

Bizzarrini GT Strada 5300 

The GT Strada 5300 was the most widely used version of the Bizzarrini. It carried an aluminium body, was usually equipped with the 365 hp engine and offered in the interior a minimum level of comfort. These included side skylight windows, a ventilation system adopted by Fiat, and a leather-covered dashboard, which in some cases was panelled in wood. Some intended for the American market models were called GT America. They largely corresponded to the European Strada.

Bizzarrini GT Corsa 5300 

The GT Corsa 5300 was designed for racing use modification of the Strada, which was uncompromisingly geared to sportiness. Bizzarrini reduced the weight of the vehicle by 40 kilograms by removing components that served comfort. These included the inner door panels, the crank windows - they were replaced by sliding windows - and the ventilation. When building the body thinner and thus lighter aluminium sheets were used. The Corsa models had additional ventilation openings in the rear window area. In at least four cases, the body was made of plastic.

Bizzarrini 5300 Spyder SI 

Largely independent are the Spyder models of the Bizzarrini 5300. Overall, three specimens were created: A prototype and two of them clearly different vehicles that went on sale. The prototype of the Spyder was developed in the second half of 1965 and presented to the public at the Geneva Motor Show in March 1966. The baseline of the vehicle was similar to that of the GT Strada 5300; however, the car had a removable roll bar and also removable roof parts. The chassis of the exhibit had not been reinforced, so the car's twisting tendency was extreme. Giotto Bizzarrini described the structure as "unstable", which changed nothing, as the roll bar was later welded firmly. The Spyder prototype did not go on sale. When, after the insolvency of the Automobili Bizzarrini, he nevertheless got into private hands, Bizzarrini installed a suitable engine at the owner's request. However, broke the windscreen after only 2000 kilometres due to the high body distortions. The prototype then stood still for nearly 30 years, before a collector bought it and provided it with a body in the style of the later "series" Spyder. After the failure of the Spyder prototype Bizzarrini constructed another open version of the 5300 with firmly welded roll bar and some reinforcements around the windshield. The body was manufactured by the Turin company Stile Italia.  From now Spyder SI (for styles Italia car called) emerged in 1967 and 1968 two copies. The first, red-painted, vehicle was made for Bizzarrinis investor Harold Sarko, the second, blue, for Domenico Iselio, owner of Stile Italia. A regular mass production failed according to Giotto Bizzarrini's lack of funding.  

Race events

The Bizzarrini GT 5300 was designed as well as its predecessor Iso A3 / C for participation in racing events. Giotto Bizzarrini had used the A3 / C in 1964 and 1965 for Iso Rivolta in various endurance races and achieved some success, including in both years class victories in the 24 Hours of Le Mans.

Even after Bizzarrini had split in the summer of 1965 by Renzo Rivolta, he continued the motorsport engagement. Bizzarrini built a new vehicle for this purpose, which received the chassis number BA4 106 and should deny all the racing inserts of the plant in the 1966 season. However, Bizzarrini could not achieve any more with the conceptually unchanged GT 5300. Bizzarrini's riders Edgar Berney and Antonio Nieri were also knocked out of service for the first race, the 1000 km Monza race, as in the prestigious Targa Florio in May 1966. The 1000 km race at Spa-Francorchamps and at the Nürburgring left Bizzarrini out of money shortage to save resources for the June 24, 1966 Le Mans race. Here Bizzarrini first appeared with his new design, the P 538, which was the preferred attention of the work. In addition to the - at that time not yet mature - prototypes Bizzarrini reported the GT 5300 for Sam Posey and Massimo Natili , who entered the race four places ahead of the P 538. The event did not succeed for the Bizzarrinis. While the P 538S crashed, Posey and Natali were disqualified because they had run over a safety line in the pit lane.

For 1967 Bizzarrini equipped the GT 5300 with a seven -litre eight-cylinder engine from Ford. The car was driven by Edgar Berney and Jean de Mortemart in the 1000 km race of Monza, but did not finish. A message for the 24 Hours of Le Mans in 1967 was not accepted because the commissars considered the car technically foul. As a result, Giotto Bizzarrini ended his factory involvement in motorsport.