The Lotus 33 incorporates the concepts used on the previous and winning Lotus 25, improving all the technical aspects related to it. The car made its debut during the 1965 season, on the occasion of the British Grand Prix, the fifth stage of the Formula 1 world championship.
The design of the model 33 derives strictly from the previous Lotus 25, which serves as the basis for the new design, taking the design of the monocoque frame to a new level, both in terms of lightness and in terms of overall frame stiffness. The Climax engine with 1500 cm³ of displacement is once again mounted on the 33.
The Lotus 33 is almost identical to the 25, therefore it can be considered as a deeper evolution of the latter, which differs mainly in the suspension layout built around the new and larger tires produced by Dunlop. In addition, the car is simplified in mechanics, in such a way as to go in search of greater overall reliability in the Grand Prix.
The engine is continuously developed by Climax, and the unit now has a power equal to about 200-210 horsepower, against only 181 of the previous version: the bore is increased, and it passes from direct to indirect injection for the 1965 season.
The 1965 season
The car took the reins of the season only at the British Grand Prix, immediately giving excellent responses with a solid victory. The same result is obtained in the following two Grands Prix in Holland and Germany, while in the three remaining events Jim Clark finishes in tenth position in Italy, while in Mexico and in the USA he is forced to retire.
The double retirement does not compromise the title race of Jim Clark, who adds to the three victories obtained with the Lotus 33, the other three obtained at the wheel of the Lotus 25, winning the second world title with the Lotus, which can also celebrate the second constructors title in its history.
The 1967 season
In 1966 Colin Chapman signed a contract with BRM for the supply of the new engine called H16, mounted on board the Lotus 43, a natural evolution of the Lotus 33, in relation to the increase of the maximum displacement allowed to 3000 cubic centimeters.
The engine, however, proved heavy, not very powerful and unreliable, and during the season Clark only won one victory at the end of the season at Watkins Glen. In 1967, after yet another retirement during the South African Grand Prix, Lotus decides to return to the 33 model, which still has the eight-cylinder Climax.
The car was used until the 1967 Dutch Grand Prix, when the futuristic Lotus 49 made its debut. Always with Jim Clark at the wheel, during 1967 the Lotus 33 successfully took part in various competitions outside the Formula 1 World Championship, winning the Tasman Cup.
The Lotus 33 concludes its history with a title in the Tasman Cup, the victory of the Formula 1 world championship both in terms of the drivers 'and constructors' standings, and six overall victories in the top flight.