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, two years 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 and bespoke 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 sports 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 production 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 which then ran another prop-shaft to drive the front wheels. The configuration allowed for the engine to be mounted longitudinally in a front-mid-ship location to improve weight bias and therefore help overall traction and handling.

1981 Lancer 2000 turbo

Similarly to 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 greatly help speed up initial development by providing a relatively instant and more stable benchmark. However, the end goal for the Group B rally car 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 in constant operation, while the other being electronically-controlled to come into operation only over 2500 rpm. This was marketed as to provide good top end performance without having to sacrifice power at the lower end of the rev range, which was a critical issue in turbocharged engines.

Mitsubishi Starion 4WD Rally – technical view

For the Starion “evolution” (ET), this engine would be 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 engines produced an output of approximately 350 BHP on full song.

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

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 racing 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).

Preparation of the prototype for the 1984 Rallye des Milles Pistes

An early prototype of the Starion 4WD Rally was able to win its class at the 1984 Rallye des Milles Pistes, on the famed French military testing grounds that is also part of the French Rally Championship, but the overall development of the car was then far from finished.

As it was often the case with such projects, it suffered from many delays, engineering problems, and seemingly second thoughts from the management as to the car’s then doubtful competitiveness in the WRC thanks to the arrival of bespoke mid-engine Group B supercars. In comparison, the Starion 4WD was rather crude with an already outdated design concept.

However, the Starion 4WD Rally would be arguably very competitive at the national level, especially in the Asia-Pacific region, where mid-engine Group B supercars were very scarce. As such, work slowly continued with an expected homologation at the end of 1986 paired with an official participation in the November RAC rally. In the interim, the Starion 4WD Rally was thus campaigned such as in the 1986 Hong Kong-Beijing Rally by Ningjun Lu and also by Danny Chau, the former finishing in second place albeit a severe crash.

Lu’s crash at the 1986 Hong Kong to Beijin Rally

Sadly, as history would turn out, news of the cancellation of Group B for the end of 1986 would effectively terminate the Starion 4WD Rally project before its completion. The follow-up Group S proposal might have been favourable for the Starion but the category remained stillborn after the FISA and BPICA members just couldn’t agree on critical points.

A theoretical last resort could have been participation in Group A, which had replaced Group B in 1987, but this would have necessitated 5,000 bespoke four-wheel drive units to be built for homologation. While the endeavour was feasible, Mitsubishi had a change of heart about the now 5-year old Starion and instead opted to use the newly introduced sixth generation Galant (VR4) model as their next 4WD Group A flagship rally car. In the early 1990s Mitsubishi would quickly reboot the project’s spirit with the legendary Lancer Evolution series.

Mitsubishi Starion 4WD Rally – Replica

A few original project members involved in the Starion 4WD Rally are said to have been later commissioned to build a replica for use in historical races by a Japanese gentleman. This particular car however differs from the original prototypes in a few aspects, such as using a right-hand drive 1987 Starion GSR-VR as its base, remaining only rear-wheel drive and closer to what the planned homologation model might have been. In early 2019, the car was put up for sale by its owner in Japan.

ANECDOTE: A Mitsubishi Starion 4WD Rally in yellow Lucky Strike colours 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:

  • 4 (presumed)
  • 5 (rumoured)
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: cast iron cylinder head: aluminium
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 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
  • N/A
  • Pajero reinforced 4WD transfer case
  • 50/50 permanent split
Clutch twin plate, dry
Chassis-body
Type
  • (H) Steel monocoque chassis, 2 door coupe design, fibreglass 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 (E) McPherson struts, carbon fibre control arms, anti-roll bar
Rear suspension (E) McPherson struts, carbon fibre control arms, anti-roll bar
Steering system rack and pinion N/A
Brakes
  • Front & Rear: vented rotors
N/A
Dimensions
length: 4280 mm (168.5 in) width: 1730 mm (68.1 in) height: 1315 mm (51.8 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) *estimated
  • (E) 1050 kg (2315 lbs)
Weight/power
  • (E) 3.0 kg/HP (6.5 lbs/HP)
Fuel tank N/A

VIDEOS


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

SPECIAL THANKS

  • Ben Miller (replica information)

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