RX Opel/Vauxhall Astra 4S – John Welch

john-welchs-vauxhall-astra-xtrac.jpg

In 1983, GM’s motorsport effort in Group B international rallying was with the classic rear wheel drive Opel Manta B400 (it was only a slightly different version of the Ascona B400 but sporting composite panels). In the WRC, the humble Manta quickly fell out of contention, making some argue that Opel should have went with the four wheel drive prototype of the rally car instead. However, by that time, it was evident that the Group B winning formula was to use a small and lightweight car as a base. In 1984, one such car within GM’s European lineup was about to be launched: the new generation Opel Kadett / Vauxhall Astra model. The E4S project was born.

astra4sbp

For detailed information about the Opel Kadett E4S / Vauxhall Astra 4S – CLICK HERE!

In 1986, when news of the cancellation of Group B hit, the aim of the car had already shifted towards competing in Group S instead. There was a total of 4 prototypes built: one with each version of the engine and all equipped with “Xtrac” four wheel drive systems. 3 were branded as the “Opel Kadett Rally E 4×4” (2 of which were tested in the 1986 Paris-Dakar rally), and the last as the “Vauxhall Astra 4S” which was tested under prototype rules in one event of the 1986 British Rally Championship.

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Paris-Dakar prototype

One of the Paris-Dakar prototypes was purchased by John Welch to compete in the British / European Rallycross series. It featured a de-stroked 2.1L Manta B400 engine turbocharged with a BMW Formula One unit that produced a claimed 650 HP. Welch would compete with the car from 1988 to 1992. His best finish was 10th place in the 1988 European Championship. He then sold off the car to a fellow competitor who stripped the drivetrain to install it in an Audi 90 coupe. Thus ended the story of the only Group S car to enter rallycross.

SPECIFICATIONS

Group/Class Formula A / Division 2 Championships: none
Years Active 1988~1992 Best finish: 10th (1988)
Engine
Type B400 “phase 4” engine, I-4, DOHC 16v, gas located front longitudinal
Displacement 2.1L
Compression ratio N/A
Output power – torque ~650 HP @ – rpm (claimed) 420 lb-ft @ – rpm (claimed)
Materials block: cast iron cylinder head: aluminium
Aspiration
  • turbocharger (BMW F1 unit)
  • air/air intercooler
Ignition electronic, firing order 1-3-4-2
Cooling system water-cooled
Lubrication system dry sump with mid-mounted twin oil coolers
Transmission
Type “Xtrac” four wheel drive 6 speed gearbox
Gearbox ratios N/A N/A
Differential ratio N/A Driver adjustable F/R ratio F28/R72 to F50/R50 hydraulic system
Clutch N/A
Chassis-body
Type T-Platform steel monocoque chassis (middle section only) 2 door coupe with integral roll cage and sump guard. Front and rear spaceframe. Kevlar body panels.
Front suspension N/A
Rear suspension N/A
Steering system rack and pinion N/A
Brakes F & R: Discs Dual circuit with servo, adjustable ratio split front to rear
Dimensions
length: 4256 mm / 167.6 in width: 1760 mm / 69.3 in height: 1393 mm / 54.8 in
wheelbase: 2500 mm / 98.4 in front track: N/A rear track: N/A
Rims – tires N/A N/A
Dry/Unladen Weight 960 kg (2115 lbs)
Weight/power 1.5 kg/HP (3.3 lb/ft)
Fuel tank 25 liters

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(C) Article by Jay Auger – website owner & author
(Images & videos are the property of their original owners)

Special thanks to:

  • Hamish Munro (spelling)

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