The Lotus Elise GT1 (also known as the Lotus GT1 and known internally as Type-115) is a race car developed for grand tourer-style sports car racing starting in 1997. 

Lotus Cars had previously been using the Lotus Esprit GT1 –a racing version of their Lotus Esprit road car– in the BPR Global GT Series since its foundation in 1994, competing in the premiere GT1 class against the likes of the McLaren F1 GTR, Venturi 600LM, Ferrari F40 GTE, and others. However, in 1997 the series became known as the FIA GT Championship, and manufacturer involvement was increased with the new international exposure. Porsche was the first to start a new breed of racing car in 1996, with their purpose-built homologation special known as the 911 GT1. This was quickly followed by announcement that Mercedes-Benz planned to do the same with their CLK-GTR for 1997.

Thus Lotus decided that in order to remain competitive in the GT1 class, let alone be victorious, they would be required to follow the route set forth by Porsche and Mercedes-Benz. However, aware that they lacked the resources available that Porsche and Mercedes had to create not only the race cars but also the production sports cars at a guaranteed loss of money for the company, Lotus decided to take an alternate route. Through interpretation of the rules for FIA GT, Lotus realized they would only need to build a single production car in order to meet homologation requirements. The car would not even need to be sold to a customer, it merely had to be built.

With this in mind, Lotus turned to designing their racing car. Lotus decided to abandon the aged Esprit chassis and instead turn to its new sportscar, the Elise. Mechanically, only the Elise's aluminum chassis was retained for the GT1, although it was heavily modified from its stock form. A new carbon fiber body that resembled the Elise was built, featuring a much longer length in order to increase the car's aerodynamic capabilities.

Debuting at Hockenheim, on 13 April (first round of the 1997 FIA GT Championship season), the three factory Elise GT1s and the privateer GBF car took to the grid. Their debut was short lived, as all four cars failed to finish, all due to alternator problems in the engine. For race two (Silverstone, 11 May), privateer GBF UK received their second car (an untested chassis bearing Nr 06 driven by Andrea Boldrini and Mauro Martini). Again the three factory cars suffered, failing to finish because of gearbox difficulty. GBF's Elise GT1s fared slightly better, with one of their entries actually finishing, although classified last and 25 laps down from the winner.

The third race of the season in Helsinki was a shorter race, featuring a smaller field (23 cars). Only three Elise GT1s were entered, but GBF was able to succeed in taking 5th place, earning them points in the championship. The other two Elise GT1s also finished the race as well, an improvement for the company.

As the season progressed, the teams began to suffer. After Helsinki was the 24 Hours of Le Mans, in which only a lone GT1 was entered due to concern over the car's ability to last 24 hours. The car had an oil pump failure after 121 laps. Returning to FIA at the Nürburgring, the full team (five cars) managed to muster only 11th place, while at Spa they achieved 8th, but at Zeltweg all five cars failed to finish again. The teams did not attempt the Suzuka round, and again could only earn 12th place at Donington and 11th at Mugello when the series returned to Europe. The final two races in the United States saw only the factory team bring two cars, in which they managed a 13th and 9th-place finish. The factory squad ended the season without any points, while GBF's points finish at Helsinki earned them 8th place in the championship.

Following the 1997 season, Lotus and its parent company, Proton, decided that the GT1 was not only lacking in pace in comparison to Porsche, Mercedes-Benz, and the older McLarens, but that it was also extremely expensive. The Chevrolet V8 was not a custom built race engine like its competitors leaving it lacking in top speed while the Lotus turbo V8 was faring even worse. The chassis was also too similar to a production car to compete with the exotic designs of other machines. The project was therefore cancelled and the factory team folded. The privateer teams also either folded or bought more capable machines.

Former factory driver Mike Hezemans of the Netherlands, feeling that the Elise GT1's main faults were in its power and aerodynamics, decided that the car should not be abandoned convinced his father Toine Hezemans to provide financial help in his project. The pair bought two former Elise GT1 chassis abandoned by the factory along with their inventory of parts. Hezemans along with his small team consisting of chief mechanic Hans Willemsen and two more mechanics, Peter Classen and Mario Van beek, set out to eliminate the faults existing in the car. They took the chassis to the Netherlands and in their small workshop, the car was extensively reworked. The front end was made longer and smoother in an attempt to increase front downforce. To replace the Elise GT1's Chevrolet V8, Hezemans turned to Chrysler, buying a pair of 356-T6 8.0L V10s producing 620 hp (462 kW) and 800 N⋅m (590 lb⋅ft) of torque which were being used in Chrysler's GT2 class racing cars. The engine was fitted in the car by extending the chassis. The Hewland gearbox was retained as the team had a small budget. The new cars were promised to compete in the 1998 FIA GT Championship season. In order to make the cars compliant to the regulations of the FIA, Hezemans turned to his friend Erich Bitter who was an independent German car manufacturer. He agreed to give the cars his firm's name and the car were named Bitter GT1s.

The cars never matched even the lackluster performance of the original Elise GT1s. The only race in which they actually competed, Silverstone, saw both Bitters failing to finish, the torque produced by the new V10 engine was too much for the gearbox. After failing to even get past initial practice at Hockenheimring, the project was cancelled.