The original Biturbo was a two-door, four-seater notchback coupé (of somewhat smaller dimensions than the BMW 3 Series of the time) featuring, as the name implies, a two-litre V6 engine with two turbochargers and a luxurious interior.

The Biturbo was initially a strong seller and brought Italian prestige to a wide audience, with sales of about 40,000 units.

Sales figures fell in subsequent years, as the Biturbo developed a reputation for poor quality and reliability.

[3] De Tomaso later sold Maserati to Fiat when he suffered losses, who grouped the company with their erstwhile rival Ferrari.

[8] Mechanical upgrades first seen on the 2.24v also began filtering through the Biturbo range in early 1989, including suspension and power steering improvements as well as ventilated front disc brakes.

[8] In 1991, the entire lineup was restyled for a second time, again by the hand of Marcello Gandini; the design features introduced with the Shamal were spread to the other models.

Inset in body-colour housings, they flanked a redesigned grille, slimmer and integrated in the bonnet; the 1988 bumpers were adopted by all models.

[9] The cars in the Biturbo family were of unibody steel construction, with a conventional layout of front-longitudinally mounted engine and gearbox.

Suspension was of the MacPherson strut type upfront and semi-trailing arms at the rear, with coil springs, double-acting dampers and anti-roll bars on both axles.

[10] In 1984 and 1985, the 2.5 L V6 models utilised a single Weber DCNVH carburetor under a smooth aluminum alloy plenum fed by twin IHI turbo chargers (one per bank of cylinders).

On initial viewing of the 1986 Biturbo engine bay, the aluminum alloy plenum is finned with a slightly different footprint and the intake manifold was specific for that model.

The customer could only choose between two paint schemes: silver or red, both paired to the lower half of the body in contrasting metallic gunmetal grey.

The cylinders were now Nikasil-coated, a more capacious fuel tank was fitted and a Sensitork limited slip differential replaced the earlier Salisbury clutch-type.

The car carried all the visual clues of Gandini's signature design language, with a more rounded grille and bonnet as on the 430, different wing mirrors and a rear spoiler.

It was also distinguished by the 15-inch disc shaped alloy wheels as also used on the 422 and 430, a black grille and trim treatment, rear deck spoiler and lower body two-tone paint.

The bonnet was adorned by two reversed NACA ducts to extract hot air from the engine bay, as on the Karif, while at the rear there were four exhaust tips.

The Maserati Racing (Tipo 331) was a more potent variant of the 2.24v with a higher power output, and was meant as an intermediate model beneath the more aggressive Shamal.

Several units have also been exported from Italy since, to other European nations; limited documentation was available, which made homologation in some countries a huge administrative challenge.

This is combined with a five-speed manual gearbox manufactured by Getrag and a limited slip differential from Maserati but suspected to use Quaife technology.

Combined with new settings on the two engine controllers from Magneti Marelli, in charge of the ignition, the fuel injection and the turbo boost management, allowed the power to increase to 285 PS (210 kW; 281 hp) at 6,250 rpm with a specific output of 142.5 PS/L.

While keeping a resemblance with the rest of lineup, only the nose and bonnet were shared between the equivalent two and four-door models; all the bodywork from the A-pillar to the rear is specific to the saloons.

Two years later, a two-litre version of the 425, the 420 (1985–86), was added for the domestic market, together with the more powerful 420 S. The 420 S sported improved handling, the twin intercooled engine[20] and the same aesthetic accoutrements of the Biturbo S: dark finish trim, two-tone paint, two-tone wheels and NACA ducts on the bonnet, delivering fresh air to the intercoolers.

The 430 was considered to be a full grand tourer, with standard leather upholstery and walnut veneered steering wheel rim, dashboard trim, door inserts, gear shift knob along with the handbrake lever.

As the top of the range 2.8 L saloon, the 430 received the full aerodynamic package, including a discreet spoiler on the trailing edge of the bootlid.

[23] Embo of Caramagna was first commissioned to develop a four-seater cabriolet version of the Biturbo, which was shown at the April 1982 Turin Auto Show,[24] but their proposal never made it to production.

The car received the full 1988 Gandini treatment, one year after the other models: rounded grille, fuller bumpers, aerodynamic wing mirrors and 15" wheels on five-lug hubs.

It was conceived to be a more luxurious offering than that earlier of the Biturbo lineup, and was therefore aimed at the same market of the large GTs of the past like the 3500 GT and Mexico.

[27] To accomplish this, it was based on the longer 2,600 mm (102.4 in) wheelbase chassis of the four-door Biturbos, and powered by the largest 2.8 litre 18-valve fuel injected V6 (hence the name 228 – 2-door, 2.8 L engine).

[27] The notchback coupé bodywork was styled by Pierangelo Andreani, and the car was wider and longer than the two-door Biturbos; the interior was also more luxuriously appointed.

A 24-valve but still carbureted prototype was shown in December 1984; the production version of the 228 was introduced at the 1986 Turin Motor Show, and 469 examples were made until 1992.