Biturbo
The Biturbo is a two-door 2+2 coupé, introduced in December 1981.[17] It is powered by a twin-turbocharged V6, rated at 180-205 PS. The Biturbo name was dropped when the car was significantly redesigned in 1988. After 1994, the two-door coupé was again significantly reworked and became the Ghibli.
In July 1983, Maserati launched the sporty Biturbo S, for the Italian market only. Power was increased by 25 PS to 205 PS at 6,500 rpm, courtesy of increased turbo boost and twin intercoolers which fed fresh air by two NACA ducts in the bonnet. The chassis was updated as well with lowered suspension and new, wider 6½Jx14" magnesium alloy wheels were fitted. The S was recognizable by its black mesh grille and the external trim (grille frame, headlight housings, window surround and Maserati badges on the C-pillar) finished in a dark bronze shade instead of chrome. 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.[18] In the same year, the 2.5-litre Biturbo 2500 or Biturbo E (for Export) was also introduced, and was joined some twelve months later by the Biturbo ES with power outputs 205 or, respectively in European- or catalysed US-specification. In 1985, all models received updates and were renamed Biturbo II, Biturbo S II and Biturbo E II. 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 second series of the Biturbo was recognizable by its new 6"Jx14" wheels similar in design to the Biturbo S wheels; the S II wheels had fully painted faces, without the silver center.
1986 brought a major change: carburation gave way to Weber-Marelli fuel injection, and the Italian market models were now known as the Biturbo i and Biturbo Si. Power outputs increased across the range, albeit at some loss of throttle response. The original square instrument cluster (from 1983 - 1985) was changed in 1986 in favour of a rounded shape instrument cluster. The intercoolers were moved from under the bonnet to a front-mounted position directly behind the grille, making the NACA ducts on the Si's bonnet merely decorative.
In 1986, a special edition of the Si called the Biturbo Si Black was introduced, whose main feature was a black on metallic grey paint scheme.105 units were made until 1988. Performance was the same as for the regular Si.[19] In 1987, Maserati launched the final car to wear the Biturbo badge, the U.S only 2.5 litre export market model Biturbo (E) Si Black. with black on metallic grey paint scheme and special interior trim. Only a total of 25 cars were known to have been produced for the U.S. market.
222
In May 1988, with the models receiving a facelift, the Biturbo name was dropped in favour of 222—meaning two-door, two-litre engine and second generation. 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. The 222 premiered at the 1988 Turin Auto Show.[20] The engine size of the 222 E export model grew from the Biturbo's 2.5-litre to 2.8-litres. A mixed velour-leather interior was standard on the domestic models, while export markets got leather upholstery as standard.[17]
1990 saw the arrival of the 2.8 L 222 SE, heir to the Biturbo ES. It inherited the latter's limited paint finish availability (red, silver or black) and the dark trim and grille, while modern aprons and side skirts (blacked out as well) came from the 2.24v.[17]
After just a year, the 222 SE was replaced by the restyled 222 SR; the SR offered adaptive suspension as an option. Simultaneously the very similar 222 4v. joined the lineup; it was a 222 SR with a 2.8 L four-valve engine, the first car to incorporate a DOHC engine in the direct Biturbo E lineage. It featured wider, 16-inch, 7-spoke alloy wheels.
2.24v
In December 1988 Maserati unveiled the most powerful variant of the two-litre models: the 2.24v, powered by the new four-valve per cylinder engine. The engine itself had been displayed at the Turin Auto Show in May 1988.[21] The 2.24v was the first model to use the more modern wraparound front and rear fascias with integrated foglights, and deep side skirts. 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.[10] It went on sale in early 1989 in Italy, the model's most important market. The 2.24v replaced the earlier Biturbo Si, which was taken out of production in the latter half of 1988.[10]
In 1991 Gandini's restyling transformed the 2.24v into the 2.24v II. The new series cars were fitted with a catalytic converter, and got Meccanica Attiva suspension on all four wheels as standard. Production of the 2.24v ceased in 1993.
Racing
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. The redesigned front end and other elements also found their way onto the remainder of the Biturbo range. It was first introduced to the press in December 1990. Only 230 units were built from 1991 to 1992 and were mainly intended for the Italian market. 173 Maserati Racing were delivered new to Italy, with the remainder presumable exported. 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.
The lowered, electronic KONI shock absorbers allowed to adjust damping on four settings, allowing for comfort or sharp handling at the flick of a switch. 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.
The choice of colours of the Racing was limited to red or black. On the interior, the only change was the paneling, painted dark grey (carbon fibre grey) instead of the standardwood trim.
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 at 6,250 rpm with a specific output of 142.5 PS/L. The torque is 374 Nm at 4,250 rpm. This engine was given the designation AM 490 in the Maserati engine reference book. The engine was made compatible with lead-free gasoline. Induction consists of two IHI water-cooled turbochargers with two air-to-air intercoolers. Changes from the 2.24v's engine include a new, lighter crankshaft, new exhaust valves (sodium filled for improved heat dissipation), new combustion chambers, new lighter connecting rods, new lighter forged aluminium pistons, and new