Mitsubishi Starion 4WD Rally – Group B Prototype

Published on: Jan 19, 2016 @ 16:50
Originally Published in: 2015 (old website)
(C) Jay Auger - website owner & author
Notice: Any form of duplication methods (including but not limited to copy/paste of text and screen capture) of the website's content is strictly forbidden.

INTRODUCTION

In 1981, due to their prior success in rallying with the Lancer 1600 GSR, Mitsubishi developed the Lancer EX 2000 Turbo specifically for Group 4 homologation. However, a year later when Group B was introduced Mitsubishi knew that their quite conventional Lancer, which was also suffering from teething troubles, would not be competitive in the new category seeing how the Audi quattro was very successful in the World Rally Championship (WRC) with its four wheel drive system. It was evident to Mitsubishi that a new Group B car was needed with the same kind of drivetrain.


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HISTORY

1982 Mitsubishi Starion Turbo

When came the time to decide on which platform the new rally car would be based on, it was obvious to Mitsubishi that it should be on their newly introduced flagship model: the Starion. Mitsubishi gave the lead of the project to Andrew Cowan of RalliArt UK. The team included the very reputable Alan Wilkinson whom had already helped develop the Audi quattro, hence bringing much needed input in developing a four wheel drive system.

1982 Mitsubishi Pajero

Although the Starion was rear wheel drive, it was found to be fairly easy to adapt the platform to four wheel drive by adding an upgraded transfer case from a Mitsubishi Pajero 4×4 behind the transmission. The configuration allowed for the engine to be mounted longitudinally in a front-midship location to improve weight bias and therefore rear traction and overall handling.

1981 Lancer 2000 turbo

As it was the case with many other manufacturers’ new rally projects, RalliArt favoured in using the engine of the previous rally car, in this case the Lancer EX 2000 Turbo’s unit, as this would help speed up development by providing a relatively instant and stable benchmark. However, the end goal for the Group B project was to use the “Sirius Dash” version of the now legendary 4G63 engine.

This powerplant was announced by Mitsubishi at the 1983 Tokyo Motor Show. It featured a special 3 valves per cylinder head that featured 2 intake valves, one is in constant operation, while the other is electronically controlled to come into operation only over 2500 rpm. It was marketed as to provide good top end performance without having to sacrifice power at the lower end of the rev range, which was critical in turbocharged engines.

Mitsubishi Starion 4WD Rally – technical view

For the Starion “evolution” (ET), this engine was bored out to 2140 cc (from 1995 cc) to maximise the x1.4 forced induction multiplier of the Group B regulations. The resulting 2996 cc adjusted figure would efficiently put the car into the 2500~2999 cc engine class which dictated the minimum weight and tire sizes that needed be met. The evolution engine produced an output of approximately 350 BHP.

The bodywork of the rally car was based on the “widebody” version of the production Starion. The most notable difference is the redesigned front end that used more reliable fixed lights rather than the pop-up units. This allowed the nose to be shortened by 6 inches, which saved a bit of weight, and permitted a larger radiator grille for extra cooling.

Further weight savings were done by using carbon fibre reinforced plastics for the prop-shafts, sump-guard, and lower control arms of the suspension. Most of the exterior body panels were moulded in fibreglass and plastic (carbon & Kevlar on evolution models); bonnet/hood, boot/trunk lid, door skins, fenders/wings, bumpers, and spoiler. The resulting weight of the rally car was said to be around 1050 kg (2,315 lbs).

An early prototype of the rally car was able to win the 1984 Rallye des Milles Pistes, the famed French military testing grounds, but the overall development of the car was far from finished. As it was often the case with such projects, it suffered from many delays, problems, and seemingly second thoughts from the management as to the car’s doubtful competitiveness in the WRC thanks to the arrival of dedicated supercars. In comparison, the Starion 4WD was rather crude with an already outdated design concept.

However, the Starion 4WD Rally would have arguably been very competitive at the national level, especially in the Asia-Pacific region. As such, work slowly continued with an expected homologation at the end of 1986 with an official participation in the November RAC rally.

Sadly, as history would turn out, news of the cancellation of Group B for the end of the same year would effectively terminate the Starion 4WD Rally project before its completion. The Group S proposal might have been favourable for the Starion but the category remained stillborn. In the early 1990s Mitsubishi would revive the project’s spirit with the now famous Lancer Evolution series.

ANECDOTE: A Mitsubishi Starion 4WD Rally is featured in the 2008 manga-derived movie “Special Stage” (Esu esu).


SPECIFICATIONS

  • (H) = Planned Homologation Version
  • (E) = Planned Evolution (Rally) Version
Group/Class B/12 PROTOTYPE
Conception / Production 1983~1986  # built: unknown
Engine
Type 4G63 “Sirius Dash”, I-4, SOHC 12v, gas located front-midship longitudinal
Displacement
  • (H) 1995 cc
  • (E) 2140 cc
WRC x 1.4 = (E) 2996 cc
Compression ratio 8.0:1
Output power – torque (E) 350 HP @ 7000 rpm (E) 253 lb-ft @ 5000 rpm
Materials block: N/A cylinder head: N/A
Aspiration
  • MHI turbocharger
  • air/air intercooler
  • Bosch electronic fuel injection
boost: 14 psi (E)
Ignition N/A
Cooling system water-cooled
Lubrication system N/A
Transmission
Type four wheel drive Starion 5 speed manual
Gearbox ratios
  • N/A
  • 1st: 3.370
  • 2nd: 2.030
  • 3rd: 1.360
  • 4th: 1.00:0
  • 5th: 0.860
  • F: 3.540
Differential ratio
  • Pajero reinforced transfer case
  • 50/50 permanent split
Clutch N/A
Chassis-body
Type
  • (H) Steel monocoque chassis, 2 door coupe design, fiberglass and plastic bonnet, tailgate, door skins, arch extensions, bumper covers, and spoilers.
  • (E) Steel monocoque chassis with roll cage, 2 door coupe design, carbon and kevlar bonnet, tailgate, door skins, arch extensions, bumpers, and spoilers.
Front suspension McPherson struts, carbon fiber control arms, anti-roll bar
Rear suspension McPherson struts, carbon fiber control arms, anti-roll bar
Steering system rack and pinion N/A
Brakes
  • Front & Rear: vented rotors
N/A
Dimensions
length: 4258 mm (167.6 in) width: 1745 mm (68.7 in) height: 1320 mm (52.0 in)
wheelbase: 2435 mm (96.0 in) front track: N/A rear track: N/A
Rims – tires N/A
Dry/Unladen Weight
  • (H) 1150 kg (2535 lbs)
  • (E) 1050 kg (2315 lbs)
Weight/power
  • (E) 3.0 kg/HP (6.5 lbs/HP)
Fuel tank N/A

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REFERENCES

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Group B - book Group B – The rise and fall of rallying’s wildest cars

Group 4 Group 4 – From Stratos to quattro


(C) Article by Jay Auger – website owner & author

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