The Sigma Model Range
The GH model was released in 1980. It sold so successfull that Mitsubishi Motors actually bought out Chrysler Australia. The big change externally was the introduction of square quartz halogen headlights and deeper bumpers front and back. Three luxury levels were again available, the SIGMA, GL and SE. Engine choices were still the 1.6 litre Saturn engine for the SIGMA and 2.0 litre or 2.6 litre Astron for the GL and SE. The 2.6 litre was now built with what Mitsubishi called the "silent shaft". Their marketing claimed this made for a smoother running engine which offered the power of a six cylinder and the economy of a four cylinder.
The GE Sigma was first released in 1977 by Chrysler Australia. Its standard features were far and above any other locally produced small car at the time. Three luxury levels were available, the GALANT, GL and SE. The lower spec GALANT came standard with the 1600cc Saturn engine and 4 speed manual. It could be optioned with the 2.0 litre Astron motor, while engine choices for the GL and SE were the 2.0 litre Astron or 2.6 litre Astron. Transmission choices were 4 or 5 speed manual, 3 speed automatic. All models had four wheel coil suspension. The SE came with optional 14" cast alloy wheels. The GE was also the first Australian built car to offer a 12 months unlimited kilometres warranty.
Mitsubishi Motors teamed up with Peter Wherrett to develop a sportier version of the GH that would appeal to "driving enthusiasts". The result was the "Peter Wherrett Special" and was released in July 1981. The model was a limited run of only 1,000 units and were all painted red with destinctive stripes on the lower doors. They all came with the 2.6 litre Astron engine and 5 speed manual transmission, an extractor exhaust system was added. Power was up from 72.9kW @ 4400rpm to 76.0kW @ 4800rpm. 15" alloy wheels were introduced with Pirelli tyres as standard. Four wheel disc brakes were also introduced for the first time to an Australian built 4 cylinder car. The already highly regarded handling of the GH was further improved with revised suspension. The interior featured Recaro front seats in a wool blend upholstery and an autographed leather Momo steering wheel.
This time Mitsubishi Motors approached Normalair-Garrett to produce a turbocharged version of the GH model (yet another first for an Australian built car). The Sigma Turbo was released in late 1981 and was available in three colours, red/black, silver/black and blue/black. The engine was the 2.0 litre Astron with a Garrett Air Research T3 turbocharger and Zenith CD carburettor. Compression was reduced to 7.8:1 with boost running at 10lb. This increased power from 64.4kW @ 5200rpm to 116.0kW @ 5200rpm. To assist cooling two bonnet vents were added, as was a unique "egg crate" grille. On the inside a "turbo boost" lamp was incorporated into the dash so the driver could tell when the engine was on positive boost.
The Sigma underwent a complete facelift with the release of the GJ model in 1982. Gone were the distinctive quad headlights, replaced with single intergrated units. The bumpers were flowed back into the body and the shape changed slightly to help aerodynamics. The handling was further improve with revised suspension settings. The interior was completely changed and featured an all new dash, the square gauges were replaced by a single panel with round instruments. Luxury levels were now XL, GL, GSR, SE and the Super Saloon. The XL still came with the 1.6 litre Saturn engine and 2.0 litre option. The GL and SE had the option of 2.0 litre or 2.6 litre Astron, whilst the GSR and Super Saloon were all 2.6 litre's.
The GK Sigma was released in early 1984. The body was further refined aerodynamically by the introduction of a rolled over nose cone, revised tail lights, revised body moulds and the placement of the rear number plate within the actual bumper. The base spec XL suprisingly still only came with the 1.6 litre Saturn as standard. Other luxury levels were no different to the earlier GJ except for the GSR. It had a revised front air dam, rear boot spoiler, moulded mud flaps, black window surrounds and door handles. It also featured all new styled "Pepperpot" alloy wheels with low profile 60 series rubber. Mitsubishi marketed the GK GSR as one of the most powerfull and exciting four cylinder "escape machines" of its time.
The last of the Sigmas' was the GN. Released in 1986 it was virtually unchanged from the earlier model. Cosmetically the body featured a revised grille and black paint treatment to the lower body. Major changes were the release of the "Astron II" performance motor and the all new "High Roof" station wagon. Luxury levels were reduced to only one, the GL. The 1600cc Saturn motor was also dropped. The 2.0 litre Astron was now the base engine, with the 2.6 litre Astron II being the only optional upgrade. As the Australian Government had introduced new laws relating to leaded petrol Mitsubishi introduced an unleaded version of the GN. The Sigma was actually sold along side Mitsubishis new model Magna during 1986 and was eventually phased out in early 1987.
