Subaru MP-1 Utility (Group B)

Published on: Feb 9, 2016 @ 17:35
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

During the short-lived Group B era, Subaru focused its official rallying ambitions in Group A with the Leone and RX Turbo models. However, Subaru would homologate two cars into Group B; the 2nd generation MP-1 Utility and later on the XT 1.8 Turbo. With large enough production numbers to be homologated in Group A, it is safe to assume that the FISA regulations on the minimal interior space is why these two cars were homologated into Group B instead.


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HISTORY

Group B itself was divided into multiple classes pertaining to engine displacement, giving the privateer-owned, smaller engine / low horsepower cars a chance to clinch their respective class honours instead of going for the impossible overall win. Cars such as the Subaru MP-1 Utility / Brat.

Ron Shapley’s Subaru MP-1 at the New Zealand Rally

The MP-1 Utility is known to have made two appearances in the WRC New Zealand Rally; driven both times by privateer Ron Shapley, the car managed a respectable 23rd (1985) and 35th (1986) overall place finish. However, the car was competing in the B/11 class (for engines between 1599~1999 cc), managing a 4th (1985) and 2nd (1986) class place finish.

Subaru MP-1 at the 1985 New Zealand Rally

Very little is known about the specs of the MP-1 rally car other than it was running in the B/11 class. However, this confirms the homologation papers who state that the car used the normally aspirated “EA-81S” 1781 cc unit instead of the turbocharged version that was also available from Subaru at the time (which would have put it in the B/12 “supercar” class with the x1.4 forced induction factor).

In twin carburetor form, the EA-81S engine was known to be able to produce around 100 BHP / 90 TQ. It is safe to assume that Shapley’s and other privateers’ rally cars were using that configuration and made approximately that amount of power.

A longer ratio 1.950 second gear was also used on the rally car, making transition into multiple low speed corners easier. Other than a basic aluminium roll cage, the rest of the car remained stock, featuring all steel body panels and normal safety glass.

The infamous Group B ban of 1986 would outlaw all B/12 and B/11 class cars, which unfortunately included the vastly under-powered MP-1. It must be noted that Subaru’s actual involvement in developing this rally car would have been slim to none and as such it does not make the MP-1 as a “works” car. The B/11 class mostly featured local dealership entries and low-budget privateers such as Ron Shapley. At the time, Subaru’s official challenge on the World Rally Championship was with the RX Turbo model.


SPECIFICATIONS

Group/Class B/11 Homologation number: B-259 (click # for the papers)
Years active 1985~86 Homologation

  • start: March 1st 1984
  • end: December 31st 1999
Engine
Type EA-81S, H-4, OHV 8 valves, gas front, longitudinal
Displacement 1781 cc  WRC = 1781 cc
Compression ratio
  • road version: 8.7:1
  • rally version: N/A
Output power – torque
  • road version: 95 HP @ 6400 RPM
  • rally version: N/A
  • road version: 89 lb-ft @ 4000 RPM
  • rally version: N/A
Materials block: aluminium cylinder head: aluminium
Aspiration
  • Normal / Natural
  • Twin DCG 306 Hitachi Carburetors
Ignition N/A
Cooling system water-cooled
Lubrication system wet sump N/A
Transmission
Type four wheel drive 4 speed manual
Gearbox ratios
  • 1st: 3.636
  • 2nd: 1.950
  • 3rd: 1.344
  • 4th: 0.942
  • R: 3.583
N/A
Differential ratios 3.70 single/dual range transfer case
Clutch single plate, mechanical
Chassis-body
Type Leone-based steel monocoque chassis with roll cage, 2 door “coupe utility” steel bodyshell
Front suspension McPherson struts, coil springs, wishbone, anti-roll bar
Rear suspension semi-trailing arm, torsion bar
Steering system rack & pinion 18.5:1 (3.8 turns lock to lock)
Brakes
  • Front: single piston calipers
  • Rear: drums
dual circuit, hydraulic
Dimensions
length: 4415 mm (173.8 in) width: 1635 mm (64.4 in) height: 1430 mm (56.3 in)
wheelbase: 2445 mm (96.3 in) front track: 1265 mm (49.8 in) rear track: 1250 mm (49.2 in)
Rims – tires
  • 13 inch
  • N/A
Curb Weight 935 kg (2060 lb)
Weight/power N/A
Fuel tank 55 litres

HOMOLOGATION / PRODUCTION VERSION

Subaru Brat

While the Group B homologation is under the “MP-1” name, this quirky coupe utility by Subaru is also known under various names; 284, Brat, Brumby, MV, MPV, Shifter, and Targa. A very far cry away from being an homologation special (which it obviously isn’t) the car was produced from 1978 to 1994 thus carries a wide range of specifications: CLICK HERE.


VIDEOS

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REFERENCES

(C) Articles by Jay Auger – website owner, main author & chief editor

  • Images & videos are the property of their original owners
  • All homologation papers are the property of the Fédération Internationale de l’Automobile (FIA): SOURCE
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