[2] Thompson and Keith Duckworth worked on a turbocharged version of the Cosworth DFL V8 engine, and its installation in the C100's chassis.

[2] However, a week after the new C100 had undergone its maiden test at Paul Ricard, albeit with a regular DFL as the new engine was not yet ready, Ford pulled the plug on the C100 project.

[2] Thompson claimed that the updated C100 developed 4,000 lb (1,814 kg) of downforce in its sprint race configuration, and that it was superior to the Porsche 956.

[3] Although Ford attempted to enter the C100 in the 1981 24 Hours of Le Mans, they did not actually attend the event;[5] instead, the car made its début at the Brands Hatch 1000 km three months later.

Manfred Winkelhock and Klaus Ludwig were selected to drive the works-entered car, and took a debut pole by 1.1 seconds from the works Lola T600 of Guy Edwards and Emilio de Villota.

[26] For 1983, Ford ended the C100 program, and sold C100 #04 to Peer Racing,[8] who promptly replaced the 4-litre Cosworth DFL engine with a 3.3-litre version.

Peer Racing entered David Kennedy and Martin Birrane in the new Thundersports series, but the pair crashed out of the season opener, held at Brands Hatch.

[30] Kennedy and Birane then retired again in the Thruxton round of the Thundersports series, after a puncture caused the suspension to fail after nine laps.

[31] Jim Crawford replaced Birrane at Donington Park, and the car took its last ever victory, winning by a lap over the Lola T594-Mazda of Pete Lovett and Jeff Allam.

[32] This would also prove to be the car's last ever finish; an accident in practice prevented Birrane and Kennedy from running the car in the Brands Hatch 1000 km,[33] whilst Kennedy and Rupert Keegan crashed out of the final race of the Thundersports season, also held at Brands Hatch.

[35] Although Ludwig was not classified at the following round, held at the Hockenheimring, Niedzwiedz won the race by over a minute, and took the fastest lap in the process.

[40] The C1/8 was then entered in the opening Norisring round of the DRM season, but gearbox issues restricted Niedzwiedz to tenth place, last of the classified drivers.

[41] Niedzwiedz dominated again in the next round of the Interserie, held at Erding,[40] but the team's attempt to run the C1/8 at the 1000 km Nürburgring ended with a driveshaft failure after two laps.

[40] For the first time that year, Niedzwiedz came second in the following race at Siegerland, beaten by Henri Pescarolo in a Joest Porsche 956.

[39] Niedzwiedz remained with the team and the C1/8 in order to defend his Interserie crown, and he began the season with a fourth at the Nürburgring and a third at Hockenheim.

[44] Jan Thoelke was selected to drive the C1/8 at Erding, and he took fifth, with the Kumsan Tiger Team taking over that car; Niedzwiedz, in his C1/4, took second.

[46] Both teams then returned to the Interserie; Konrad replaced Niedzwiedz at Zakspeed, but was not classified after not competing in the second race, whilst Thoelke came home sixth.

[44] Niedzwiedz finished the season in ninth place in the driver's championship, whilst Thoelke was 13th, Ludwig 18th, and Konrad 19th.

[39] Zakspeed selected Dauer to drive their C1/8, whilst Thoelke drove in several events in his C1/8, both as a privateer and under the Derichs Rennwagen banner.

[39] The first appearance of 1986 for both C1/8 entries came at the Hockenheim round of the 1986 Supercup, which had replaced the DRM; Dauer retired, whilst Thoelke finished ninth.

[48] Both teams ran at the next ADAC Supercup event, which was the 100 Miles of Norisring and also formed part of the World Sports Prototype Championship; both cars retired without completing half of the race distance.