GJ (1982–1984)
The redesigned GJ Sigma was released in March 1982, based on the 1980 Japanese domestic market Mitsubishi Galant. While a complete redevelopment was done for the sedan models, the wagon models in fact were new only from the firewall forward—the rest of the bodyshell was still GH based. Engine and transmission offerings remained as before, but received power and torque boosts; the 2.0-litre now produced 70 kW and 152 Nm and the 2.6-litre 76 kW and 192 Nm.
In February 1983, Mitsubishi launched a special edition Sigma GL Satellite.[24] Priced $1,000 below the GL luxury level, the Satellite was built in sedan and wagon versions, with air conditioning, five-speed manual or automatic transmission all as options.[25] However, two-tone paintwork, a laminated windscreen, AM/FM radio, adjustable steering column, intermittent windscreen wipers and a heated rear window were fitted as standard equipment.[25]
The SE model featured cut pile carpets, a tachometer, overhead reading lamps, door step lamps, rear footwell lamps, four-speaker AM/FM/MPX stereo radio/cassette system, remote boot and fuel cap releases, adjustable lumbar support and tilt for the driver seat, and tinted side windows.[26]
A sporting model, the Sigma GSR, was also released with either 2.0 or 2.6-litre engines offered with either automatic or manual transmissions. Features included alloy wheels, four-wheel disc brakes, a sports steering wheel and blackouts, particularly on the window frames and doorhandles.
June 1983 saw the entry-level Sigma rebadged as the Sigma XL, to coincide with the trim level designations on MMAL's small car, the Colt.
October 1983 saw the release of the luxurious, Sigma Super Saloon.[27] Produced as a limited edition of 500 cars and placed above the SE trim level from which it derives, it came only with the 2.6-litre in either five-speed manual or three-speed automatic.[26] The five-speed manual fitted was of Japanese origin, rather than the BorgWarner Australia unit previously fitted to Sigmas, and the suspension received a re-tune.[28] The Super Saloon featured two-tone metallic paint and crushed velour upholstery for the interior.[26] Two paint and trim combinations were offered—blue upper body with silver lower body and blue interior—or dark brown/light brown exterior with a bronze interior.[26] The Super Saloon introduced standard power steering, power windows and central locking—features that also became optional on Sigma GL, SE, and GSR trims.[27] The central floor console was also revised to accommodate the power window and central door locking switches.
The GJ series Sigma had the distinction of being the only Australian car during the 1980s to be exported to Europe (Chrysler previously did this with the Australian Valiant). The car was sold in the United Kingdom, in both sedan and wagon models, under the marque Lonsdale.
GK (1984–1985)
The GK Series was released in March 1984. It was a comprehensive facelift, both outside and in. Externally the GK was changed by having a new bonnet and a shallower grille, while at the rear new taillight clusters (which had actually appeared in certain overseas markets in 1982) and rear valance were fitted, the registration plate being relocated below the bumper. Internally the specifications and trim of the models had changed. Seats were different in certain models, particularly the GL, and all models had the option of power windows (although rare), an option not available in most previous models.
The Sigma XL was the entry-level model of the range and came with either the 1.6 or 2.0-litre engines. In the SE, velour seats with lumbar control, adjustable headrests and a fold-down rear seat armrest with boot access were fitted. Reading lights incorporated into the roof-mounted dome light and built into the rear pillars were now a stock feature on the SE model Sigma. Power assisted steering was also an option along with electric windows. The SE model Sigma had stock dual line striping around the car, with chrome bonnet indicators.
Chrome detailing (around gauges and air vents, which often had a tendency to peel off) was replaced by black painting, and the door trim was now two-tone in certain models. A few other slight changes were included in the GK Sigma, for example, the boot was fully lined with carpet and also featured a plastic protector for the lights. A painted boot with only base carpet was used in the GN Sigma, with no plastic light protector. Also, red courtesy lights were built into the bottom of the doors on the SE model.
As for the mechanics of the car, the GK was unchanged from the GJ, while the SE model featured rear disc brakes as standard. The GSR received a sportier front air dam
GN (1985–1987)
Released in July 1985, the GN was an update, but also a rationalization of the previous Sigma range due to only being offered in GL trim. The range was rationalized due to the April 1985 release of the Mitsubishi Magna front-wheel drive range, which was developed eventually to replace the Sigma in Australia.
The GN range had a number of external trim changes over its predecessors, notably a black trim line around the base of the body, and the deletion of the wrap-round chrome strip seen on the previous model. The grille was remodelled, resembling the SE grille of the previous model, and new hubcaps were used with alloy wheels from the previous SE models optional. The largest change however, concerned the wagon models. To freshen the model before the impending release of the Magna wagon (which was being developed at that time, for a 1987 release), a new higher roof (dubbed "high roof") was developed for the car, which helped to improve the car's overall cabin space. It gave the wagon a unique appearance from its predecessors, particularly as it incorporated a roof-mounted spoiler.
Engine-wise, the GN Sigma was offered either with the Astron 2.0-litre (70 kW at 5600 rpm and 152 Nm at 2400 rpm) or the Astron II 2.6-litre (83 kW at 5200 rpm and 200 Nm at 2400 rpm) units. The Astron II had a few changes over the previous models, notably a newly designed head with hydraulic tappets (replacing the manual tappets in previous Astrons) and flat-top pistons. The oil pressure switch was now located at the rear of the cylinder block. In December 1985, the 2.0-litre versions were dropped, as Mitsubishi did not believe it warranted the conversion to unleaded fuel. Unleaded was introduced in Australia in January 1986.
Mitsubishi launched GL Satellite limited editions of the GN series in c. October 1986, adding air conditioning, unique striping, headlamp protectors, front and rear