Fiat never quite managed to crack the US market with its mainstream offerings, but sports cars were another matter, though: American enthusiasts bought nearly 60% of all the X1/9s ever produced. That moniker originated as the car's project code, but if you've ever wondered how that came to be and why, read on...
Starting over
Fiat implemented its internal project numbering scheme in early 1946 when the company was planning its product development for the post-war years.
Aiming to bring some order into the growing number of models and designs, Fiat's legendary technical director Dante Giacosa established a simple three-digit numbering system, the first of which was to be 1 for passenger cars, 2 for light commercial vehicles, 3 for buses, and so on.
Over the following years, knowledge of such numbers remained confined within the company's walls until the launch of the 124 family sedan in the spring of 1966.
The "X" factor
The model was the first Fiat whose project number became a commercial name, a practice the Italian company would follow for over a decade.
One unintended consequence of that decision was that once skilled motoring journalists got wind of one or more project numbers, they could easily second-guess what was going on at Fiat, much to Giacosa's displeasure.
Inspired by Provslav Rakovic, the general manager of the Yugoslav firm Zàstava (which produced Fiat models under license), who often used the letter "X" when discussing future models, Giacosa began referring to new car projects as "X1," starting from the "X1/1" project that resulted in the Fiat 128 launched in 1969.
The same year saw the debut of the Autobianchi A112 ("X1/2") and the Fiat 130 ("X1/3"), while the "X1/4" arrived in 1971 as the Fiat 127, the last of the company's models to be designed under Giacosa's watch.
Epilogue
Establishing when exactly Fiat stopped using these "X" project codes isn't easy, given they were usually replaced with a three-digit number as a vehicle got closer to production, and a proper list of them probably never existed.
I can confidently say that production car projects were still issued "X" codes at least until 1978, even though the highest such code I've seen is "X1/75," belonging to an intriguing prototype for a highly fuel-efficient small car from the early 1980s that's preserved in the Stellantis Heritage Hub in Turin.
The X1/9, however, remains the only Fiat whose "X" project code was used as a commercial name, and now you know that's partly owed to an unwitting engineer from Yugoslavia and the shrewdness of the Italian motoring press.