Opel Ascona B 400 (Group 4 / B)

Published on: Feb 5, 2016 @ 19:43
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.

Opel Ascona B400 4.jpg

INTRODUCTION

Brainchild of Tony Fall, the Group 4 Ascona B 400 was developed to replace the Group 1/2 Kadett GT/E and put Opel on top of the international and World Rally Championship (WRC) scenes.


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HISTORY

First shown at the Frankfurt Auto Show in September of 1979, the “B 400” variant was an homologation special produced especially to make the Ascona eligible for rallying’s top Group 4 category. It was aimed to compete directly against the Ford Escort RS1800 and Fiat 131 in both national and international rallies. As such, the car featured a traditional chassis paired with rear wheel drive. Engine specialist Cosworth (which had greatly helped Ford achieve success with their Escort) was given charge of building the engines while specialist Irmscher would take care of the bodywork modifications.

As it was often the norm in racing, the plan was to use the engine from the outgoing rally car, in this case the Kadett GT/E’s 2.0L unit, but these did not produce enough power for Group 4 competition. Therefore, many alterations were made to the engine to fix the output problem; the cylinders were bored out to make use of larger pistons, different connecting-rods, and used the much beefier crankshaft of Opel’s CIH diesel engine.

Opel Ascona B400 ERF (7).JPG

The new 2420 cc engine gave rise to some massive power outputs while using the Cosworth 16 valve head: in race trim the normally aspirated engines delivered a base power of 230 BHP with a maximum expected output of 340 BHP (albeit with much reduced reliability).

About a year later in 1980, the FISA officially announced the approval of the complete revamp of its regulations which would introduce the new Group B category set to begin in 1982. Not long afterwards in 1981, Audi introduced the quattro which would soon become the Ascona’s fiercest competitor in the WRC.

Furthermore, the second generation of the Ascona was soon to be replaced by a third generation. As such, Opel chose the shift its motorsport branding image to the new second generation of the Manta (the Ascona’s sister car) to build their upcoming Group B machine instead. Both cars would be subsequently developed at the same time.

opel-ascona-b400-drawing

In 1982, per the transition rules allowed, the Ascona was transferred from Group 4 into Group B. Near the end of the year, Opel would implement a few improvements to the car, also known as “phase 2”, in hopes to retain the competitiveness of the car while the Manta replacement was being finalised. These improvements mainly featured the switch to composite materials for body panels and screens.

The Ascona gave the Audi quattro a good fight in the WRC but fell short of the manufacturers championship. It did, however, provide Walter Röhrl with his second drivers title. As history would unfold, that would be the last time that a driver won the WRC championship with a rear wheel drive car, hence securing the Ascona’s spot in motorsport history.

RohrlAscona.jpg

In early 1983, Ari Vatanen would give the Ascona a fairy tale ending with a victory at the Safari Rally, its very last event. For the next rally, Opel had to forcibly retire the Ascona and switch its international Group B rallying efforts to the further improved Manta B 400 (also known as “phase 3”) to retain the eligibility of scoring points in the WRC.

Ultimately, the bad timing of its introduction and the infamous engine teething issues prevented the Ascona from achieving a long and successful rally career on the international scene. However, many privateers would continue to rally the car and achieved much success in national events. Today, the car is a mainstay of historic rallies around Europe.


RALLY CAR SPECIFICATIONS

The following specs are for the “phase 2” Group B version.

Group/Class B/12 Homologations:

  • # 666  (Group 4)
  • B-221 (Group B)
  • click on # to see papers
Years active 1980~1986 Homologation start:

  • November 1st 1979  (Group 4)
  • November 1st 1982  (Group B)

Homologation end:

  • December 31st 1987 (Group B)
Engine
Type 4S “phase 2” with Cosworth “crossflow” cylinder head, I-4, DOHC 16v, gas located front longitudinal
Capacity 2420 cc WRC: 2420 cc
Compression ratio 11.5:1
Output power – torque 270 HP @ 7000 rpm  214 lb-ft @ 5000 rpm
Materials block: cast iron cylinder head: aluminium
Aspiration
  • natural/normal
  • 2 x Weber DCOE 48 carburetors
Ignition electronic, firing order 1-3-4-2
Cooling system water-cooled
Lubrication system dry sump 15 liters
Transmission
Type rear wheel drive 5 speed getrag gearbox
Gearbox ratios constant input: 1.038/1 (27/26)
1st: 2.337/1 (36/16)
2nd: 1.671/1 (34/21)
3rd: 1.355/1 (30/23)
4th: 1.163/1 (28/25)
5th: 1.000/1 (direct)
R: 2.650/1 (41/16)
constant input: 1.652/1 (38/23)
1st: 3.717/1 (36/16)
2nd: 2.403/1 (32/22)
3rd: 1.766/1 (31/29)
4th: 1.263/1 (26/34)
5th: 1.000/1 (direct)
R: 4.230/1
Diffrential ratio from 6.1/1 to 3.180/1 hypoid spiral bevel gears, 75% – 80% limited slip rear differential
Clutch dry – double plate
Chassis-body
Type steel monocoque chassis with steel roll cage, steel front subframe for front suspension. 2 doors coupe steel/plastic bodyshell with plastic bonnet, front and rear bumbers and spoilers
Front suspension double unequal wishbones with coil springs, Bilstein gas shock absorbers and anti-roll bar
Rear suspension live axle with 4 longitudinal links, panhard rod, coil springs and Bilstein gas shock absorbers
Steering system rack and pinion
  • 15.5:1
  • 2.7 turns lock to lock
Brakes
  • FRONT & REAR: ventilated disks with 2 or 4 piston calipers
adjustable dual circuit with servo
Dimensions
length: 4320 mm (170.0 in) width: 1760 mm (69.3 in) height: 1360 mm (53.5 in)
wheelbase: 2518 mm (99.1 in) front track: 1387 mm (54.6 in) rear track: 1375 mm (54.1 in)
Rims – tires 5″~8″ x 14″~15″ Michelin TRX 135-250TR290, 205/50 R14
Dry/Unladen Weight 1050~1100 kg (2315~2425 lb)
Weight/power 3.9 kg/hp (8.6 lb/hp)
Fuel tank 60 lt, 80 lt, or 110 lt

HOMOLOGATION VERSION

Opel Ascona 400.jpg
Opel Ascona B 400

The “B” stands for the second generation of the model, while the “400” moniker comes from the required units aimed specifically to acquire Group 4 homologation for use in rallying. As such, only 400 of these special two-door Asconas were produced in 1979.

The car featured a few improvements over the normal Ascona production models, more prominently in the basic “phase 1” engine that produced 144 BHP in street trim. The wide arches, body kit, and decals were optional features that were fitted out of factory by German specialist Irmscher.


ROAD CAR SPECIFICATIONS

Class Sports Homologations:

  • # 666  (Group 4)
  • B-221 (Group B)
  • click on # to see papers
Years produced 1979 (400 units) Assembly: Germany
Engine
Type “24E”, I-4, DOHC 16v, gas located front longitudinal
Displacement 2420 cc
Compression ratio 9.7:1
Output power – torque 144 HP@ 5200 rpm 155 lb-ft @ 3800 rpm
Materials block: cast iron cylinder head: aluminium
Aspiration
  • natural / normal,
  • Bosch L Jetronic
Ignition electronic, firing order 1-3-4-2
Cooling system water-cooled
Lubrication system N/A N/A
Transmission
Type rear wheel drive 5 speed gearbox
Gearbox ratios N/A N/A
Differential ratio N/A N/A
Clutch dry – single plate
Chassis-body
Type steel monocoque 2 door sedan chassis. Optional body kit consisting of; Irmscher front & rear wheel arch extensions, side skirts, rear spoiler
Front suspension double unequal wishbones with coil springs, Bilstein gas shock absorbers and anti-roll bar
Rear suspension live axle, radius arms, panhard rod, coil springs and Bilstein gas shock absorbers
Steering system rack and pinion N/A
Brakes N/A N/A
Dimensions
length: 4320 mm (170.1 in) width: 1670 mm (65.7 in) height: 1360 mm (53.5 in)
wheelbase: 2518 mm (99.1 in) front track: 1387 mm (54.6 in) rear track: 1375 mm (54.1 in)
Rims – tires 6J x 14
  • FRONT: 195/60 VR 14
  • REAR: 195/60 VR 14
Curb Weight 1082 kg (2385 lb)
Weight/power 7.5 kg/HP (16.6 lb/HP)
Fuel tank N/A

VIDEOS


REFERENCES

 Affiliates Program – (free delivery worldwide!)

 Group B – The rise and fall of rallying’s wildest cars (English)

Group 4 Group 4 – From Stratos to quattro (English)

  • Any purchase you make through the Affiliates program helps support the Shrine!

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

  • Images & videos are the property of their original owners
  • All homologation papers are the property of the Fédération Internationale de l’Automobile (FIA): SOURCE
  • Eifel Rallye Festival Pictures used under permission – McKlein Publishing
  • DISCLAIMER / LEGAL NOTICES
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