The Alfa Romeo 75 did not have multiple chassis generations, but rather a continuous evolution process
divided into two distinct phases, known as Series 1 and Series 2.
First Series (1985–1988)
Launched in May 1985 with carbureted four-cylinder engines (1.6, 1.8, and 2.0 liters), an injected 2.5 V6,
and a 2.0-liter turbodiesel supplied by VM Motori. Early versions featured orange lenses on the taillights
and side turn signal repeaters.
In 1986, the 1.8 Turbo was added, which used a Garrett T3 turbocharger with an intercooler and oil cooler to
extract 155 hp from the Bialbero four-cylinder block. This version served as the basis for the homologation
of FIA Group A touring cars, requiring an initial minimum production of 5,000 street units.
The year 1987 marked a major mechanical revolution with the launch of the 2.0 Twin Spark (TS). Alfa Romeo's
engineering redesigned the cylinder head of the two-liter engine to adopt two spark plugs per cylinder
(promoting a more homogeneous combustion), shallow hemispherical combustion chambers, Bosch Motronic digital
electronic injection, and the pioneering variable valve timing system on the intake camshaft. The engine
generated 148 hp and drastically improved the dynamic balance of the 75, as the aluminum engine was much
lighter than the V6 blocks, eliminating the understeer tendency when entering tight corners. In the same
year, the 3.0 V6 America emerged, increasing the Busso engine's displacement to 2,959 cc to yield 188 hp.
Also in 1987, Alfa Romeo produced the rare 75 Turbo Evoluzione, limited to exactly 500 examples assembled
between March and April. This version was necessary to homologate additional aerodynamic and mechanical
modifications for the 1987 WTCC championship. Under FIA rules, turbo engines suffered a capacity multiplier
of 1.7 for competition class purposes. The original 1,779 cc engine would equal 3,024 cc, placing the 75 in
Class 1, which would put it at a disadvantage against larger cars.
To put it in Class 2 (up to 3,000 cc), Alfa Romeo reduced the cylinder bore from 80 mm to 79.6 mm, decreasing
the physical displacement to 1,752 cc. This resulted in a corrected displacement of 2,978 cc (1752 x 1.7).
The Evoluzione's block (Tipo 061.58) featured thicker cylinder walls to withstand extreme turbo pressures on
the tracks, a revised cylinder head, and a Garrett T03 turbo tuned to 0.9 bar in the street version.
Although officially declared with the same 155 hp as the conventional turbo, the engine generated about 175
real hp in civilian use.
Second Series (1988 to 1992 Facelift)
Introduced in the fall of 1988 for the 1989 model year, Series 2 brought styling and mechanical engineering
changes. On the exterior, the vehicle received a new front grille with integrated grey horizontal fins and
all-red taillight lenses. The instrument panel was updated with revised graphics and a grey background.
The most significant alteration of Series 2 was the installation of the "isostatic" gear selection system.
The chronic locking and imprecision of gear shifts in previous models — caused by the long path between the
console lever and the rear gearbox — were solved by a new set of balanced rods and pivots, accompanied by a
new single-disc clutch and redesigned gear synchronizers.
To meet Europe's pollution limits, multi-point electronic injection (i.e.) was extended to the smaller
engines, eliminating the old twin-choke carburetors. The 1.8 engine gained the 1.8 i.e. version (122 hp)
and, at the end of 1989, the 1.6 received the 1.6 i.e. version (107 hp). A new 2.4-liter turbodiesel engine
from VM Motori, generating 112 hp and equipped with an intercooler, was added to the catalog to meet the
European long-distance market.
In 1990, Alfa Romeo updated the top-of-the-line variants. The 1.8 Turbo engine received the Quadrifoglio
Verde (QV) tuning, reaching 165 hp. The top of the line became the 3.0 V6 QV "Potenziata", which abandoned
the analog Bosch L-Jetronic injection in favor of the integrated digital Bosch Motronic system (shared with
the Alfa 164), raising the power to 192 hp. This large-displacement version received new anti-roll torsion
bars, stiffer shock absorbers, and 15-inch alloy wheels.
Between 1991 and 1992, in the final months of manufacturing, numbered editions emerged such as the ASN
(Allestimento Sportivo Numerato), which featured grey velour Recaro seats, exclusive 14-inch Speedline alloy
wheels, and a numbered identification plaque on the dashboard. The special editions Indy, Imola, and Trofeo
concluded the production cycle at the end of 1992, making way for the definitive introduction of the Alfa
Romeo 155.