In 1971 Abarth became a company fully controlled by Fiat, with a managing director appointed by the latter. The first was Giovanni Sguazzini, who, at the time, was also in charge of a small Rally Department born in the meanders of Fiat's branch office in Corso Bramante, Turin, which, later on, was moved to premises of its own in Corso Giulio Cesare.
The decision to join forces was the logical outcome of this development. Fiat's Reparto Rally was moved to Corso Marche 72, into a building adjacent to the historic premises at no. 38, that was used for customer services and spare parts.
Direct control by Fiat opened up new prospects, providing for a multiplicity of diversified activities.
A first major result was the birth of the Autobianchi A112 Abarth. The experience gained on race tracks with the Fiat type 100 engine, conceived for the Seicento with a displacement of 633cc, which was then increased to 850 and 1000cc for the vehicles bearing the Scorpion badge, made it possible to set up a car that was nimble, reliable, powerful, and able to re-launch the Abarth car concept for a huge audience.
Engine production was entrusted to the company, which set up a line to produce the engine, with some of its main components, up to its release and shipment to the Desio plant for installation on the car. The future of industrial operations was thus ensured for a few years: the 58 BHP 998cc was followed by a 1050cc version delivering 70BHP, which made it possible to provide employment for the workers who otherwise would have lost their jobs when it became clear that the production of the famous Abarth Exhausts was to be phased out.
Besides the production lines, the management of Abarth, in the hands of Renzo Avidano, Carlo Abarth’s right-hand man during the "roaring years", developed activities such as the construction of prototypes for Fiat's production cars (e.g., models 126 and 128), the production of a 2000cc two-seater Sport car for a vehicle class that dominated the European racing scenario of the time, as well as a number of engines designed to compete with the BMW Motorsport that reigned over the Sport 2000 and Formula 2 car market.
One activity prevailed, however. Thanks to its customers Fiat had discovered rallying, and the design and development of cars for rallying became the core business at Corso Marche.
On 1 October 1981, Abarth & C. ceased to exist and was replaced by Fiat Auto Gestione Sportiva, a division of the parent company specialising in the management of automotive sports programmes that would remain in operation through to the end of 1999, when it changed to Fiat Auto Corse S.p.A.

The commitment to rallying had reaped three world titles (in 1977, 1978 and 1980), and laid the foundations for the commitment to develop, produce and manage the future top cars of the Fiat Group, designed to claim the manufacturers’ world championship title.
In 1982, the FISA, now FIA, changed the rules governing rallying to admit small run cars (B Group cars, produced in runs of just 200 units) next to the high volume A Group (5000 units) cars.
Following the decision to diversify the brand activities – it was decided that Lancia would run in the Group B class and Fiat in Group A races - Abarth began working on the development of two models, one earmarked for the manufacturers’ world championship and the other for private customers. Respectively, the models were the Lancia Rally, better known as the SE037 (its project number that was to become its "nearly official" designation) and the Fiat Ritmo Abarth.
After that, for the Lancia brand, Abarth developed and built an all-wheel-drive car for the B Group, the Delta S4. When the B Group was suddenly abolished, they were asked to convert the Delta 4WD into a Brand Icon, an assignment they fulfilled so successfully that the resulting vehicle went on to win six consecutive world rally titles. The role of Abarth in this project no longer included responsibility for the production process, but consisted of developing the car for competitions and proposing variants for the following models, with a view to enhancing the competitiveness of the vehicle in the light of regulations that were frequently revised and under the pressure of rival models struggling to find a way to stem the tide of the "Delta phenomenon".
Work on behalf of the Fiat brand was limited to models of lesser importance competing in trophy tournaments, plus a foray into the field of vehicles without engines: a bobsleigh studied for the Italian Winter Sports Federation.
In that period, the Abarth race department was physically merged with Lancia Corse, as the latter moved to Corso Marche 72, but retained its own identity and independent racing activities, with the Group 5 Beta Monte Carlo, and the LC1 and the LC2, which competed for the manufacturers’ world title in endurance contests.
The cars were designed by Dallara, a company operating in Varano de’ Melegari, and was managed by the Lancia racing team, headed by Gianni Tonti and staffed by the people responsible for the success of the Stratos and the Fulvia.
Abarth continued working for Lancia until the brand retired from the world stage in 1993, a move decided by the Fiat management to make room, and provide funding, for the Alfa Romeo brand.

As we have seen, when Alfa Romeo was acquired by Fiat in 1987, Corso Marche was affected as well; the introduction of this new division put an end to the sports activities of the Lancia brand.
As for Alfa Romeo, after an initial period of independent activity (albeit with Alfa Corse working under Giorgio Piantà, who had left his position at Abarth as manager of road going vehicle quality to become the "prime mover" in re-launching the sports programmes of the Milan-based company), the ties between the two organisations, Abarth and Alfa Corse, became closer and closer.
During the initial stage, the Milan-based Alfa brand, which had just ended its participation in Formula 1 racing, began to look for new outlets, first with the development of the 164 Procar in cooperation with Brabham, then with the supply of engines for Formula Indy, with a view to establishing a foothold in the US market.
In 1988 the two engineering teams - Abarth and Alfa Corse - started cooperating, first on the development of a sport car prototype, the SE048, a project that came to a premature halt, and then on a series of touring car models using the frame of the Alfa 155, a car that had scored wins in the Italian championship in 1992, the German championship in 1993, and the British championship the following year, always according to different sets of rules for which Abarth had to devise appropriate adaptations.
The penchant for rallies, however, continued to find expression in the participation in single-brand trophies, where the Fiat Cinquecento competed at various levels and with various versions; Fiat management was willing to tolerate rallying as long as it was kept as a low-profile activity.
By mid-1994, the historic site of Corso Marche 38 had been engulfed by the fast-sprawling city, which had reduced the vehicle testing ground "Campo Volo" to a single lane a few hundred metres long; using the engine test rooms had become a problem, the noise having come under criticism by the apartment-blocks and schools that had arisen in the immediate proximity.
New facilities were opened up at the Lancia plant in Chivasso, where production activities had been discontinued and a viable test track was available for the new models.
Following the move to Chivasso, the Corso Marche engine test room was closed on a permanent basis and the bulk of engine design and construction activities was relocated to Settimo Milanese. This achieved a division of labour, vehicles and gearboxes going to Abarth in Chivasso, and the engines to Alfa Corse.

1996 ended with a revolution: the International Touring Car Championship (ITC) was suppressed, swept away by its exorbitant costs and the decision of two major players, Alfa Romeo and Opel, to quit the stage where they had been struggling against the technical and political superiority of Mercedes. A change in leadership took place while the racing season was in full swing: Giorgio Piantà was suddenly dismissed and replaced by Francesco Galletto, in charge of the management of financial resources of Fiat's technical office. After an inevitable, but short, period of stasis, during which many resources were allocated to tasks relating to Fiat production vehicles (on-track tests to prevent accidental airbag firing, the design of vehicles for the disabled, support for the production of a small run of taxi cabs, assistance with the design of the 156 GTA), race car design activities were resumed. For Alfa, this opportunity to turn the page coincided with the launch of the 156, a model that would be developed in Chivasso to suit the regulations of different championships, such as the Superturismo, the Superproduzione and the Super 2000 championship, where Alfa made a successful debut, taking the European title in 2002.
For the Fiat brand, instead, this period allowed a return to a larger vehicle - the Punto Kit and the Super 1600, for competition in the top-level rally formula: besides selling more than seventy cars, after many years Fiat again took outright first place in an Italian rally championship.
In terms of internal organisation, the management of the Alfa 156s was entrusted from the start to the Cremona-based Nordauto racing team headed by Mauro Sipsz: the ties with this organisation became increasingly close, culminating with a merger and the foundation, on 1 July 2001, of NTechnology in Chivasso and Milantech in Settimo Milanese, two structures devoted to the development of race cars and engines for all brands.
The adventure of NTechnology lasted until 31 December 2005, when the operation passed under the total, exclusive control of Fiat and its name was changed to an anonymous "NewBusiness16". This paved the way for the return of Abarth, which began a new life in 2007.