Opel Manta B 400 (Group B)

Published on: Jan 19, 2016 @ 17:56
Originally Published in: 2014 (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 Manta B 400 Rally Car


In mid-1983, as part of GM’s continued international motorsport branding effort, Opel officially made the transition into Group B from the Group 4 Ascona B 400 with its upgraded sister car, the Manta B 400. Opel’s use of a conventional rear-wheel drive production car would however make it almost instantly obsolete to the bespoke Group B competition.



Since 1981, both the Group 4 Ascona B 400 and the future Group B contender, the Manta B 400, had been developed simultaneously for use in the World Rally Championship and other rally series.

Opel Manta B 400 – Technical View

Compared with the Group 4 Ascona, the Group B Manta made full use of Kevlar body panels; the front air dam / fascia, front wings (fenders), bonnet (hood), doors, rear arches, boot (trunk) lid and rear spoiler – this saved about 70 kg (150 lbs) of weight over the Ascona. The Manta was also a bit longer and lower, with its engine sitting a bit further back in the chassis, the latter upgraded to “phase 3” to help increase its reliability while producing a bit more horsepower than its predecessor. For the rest, the specifications of the two sister cars were very similar, including use of the same engine.

Phase 3 Engine

In the 1982 season, since the Ascona gave the Audi quattro a very good fight, there was high hopes that the new Manta, upgraded to the more permissive Group B rules, would yet remain competitive even though it sported a classic rear-wheel drive layout and a naturally-aspirated engine. However, in its inaugural 1983 WRC season, the Manta was instantly outclassed and could only watch the fight between Audi and Lancia without being able to truly impose itself. The only highlight being a 3rd place podium at the year’s RAC Rally in the capable hands of Jimmy McRae.

In 1984, overwhelmed by the fierce competition at every turn, the car sadly fell further down the WRC leader-boards even though Rauno Aaltonen steered his Manta to a 2nd place finish at the Safari Rally.  By then, Opel’s international efforts were basically abandoned in favour of developing a four-wheel drive and bespoke Group B supercar of their own: the Kadett E 4S.

The Opel Manta B 400 however proved to be a major contender in national rallies where the level of competition was lower and featuring similar opposition. This was particularly the case in Great Britain, Ireland and Germany national championships where local star drivers such as Jimmy McRae, Russel Brookes, Austin MacHale and Erwin Weber won their share of titles from 1983 to 1986 while driving Mantas.

The infamous Group B ban of 1986 would not stop the Manta B 400’s rally career since it was allowed to continue competing in some national series, including Great Britain and Ireland, often raking podiums alongside its Ascona B 400 sister car in the hands of talented privateers up until the early 1990s. The two Opels are now a mainstay of historic rallies across Europe, also participating in exhibition events such as the Eifel Rallye Festival.


In 1982, as the Audi quattro started to run circles around the competition at the slippery events, Opel team manager Tony Fall ordered that a four-wheel drive (4×4) prototype of the Manta B 400 be built. The project was ultimately cancelled but way more information about that car can be found by clicking here! Another interesting project was started at Opel around the same time that the Manta B 400 was being finalised: the Kadett D 400.


Group/Class B/12 Homologation number: B-237 (click to see papers)
Years active (WRC) 1983~1986 Homologation

  • start: March 1st 1983
  • end: December 31st 1989
Type 4S “phase 3” with Cosworth “crossflow” cylinder head, I-4, DOHC 16v, gas located front longitudinal
Displacement 2410 cc WRC: 2410 cc
Compression ratio 11.2:1
Output power – torque 275 HP @ 7200 rpm 221 lb-ft (300 Nm) @ 5200 rpm
Materials block: cast iron cylinder head: aluminium
  • natural / normal
  • 2 x Weber DCOE 50 carburetors
Ignition electronic, firing order 1-3-4-2
Cooling system water-cooled
Lubrication system dry sump with twin oil coolers 15 lt
Type rear-wheel drive Getrag 5-speed gearbox
Gearbox ratios constant input: 1.652
1st: 3.717
2nd: 2.403
3rd: 1.766
4th: 1.263
5th: 1.000
R: 4.230
constant input: 1.038
1st: 2.337
2nd: 1.671
3rd: 1.355
4th: 1.163
5th: 1.000
R: 2.650
Differential ratio from 3.170 to 5.175 ZF hypoid bevel gears, 75% limited slip rear differential
Clutch dry – double disc
Type steel monocoque chassis. 2 door coupe with integral roll cage and sump guard. Kevlar bonnet, boot lid, front and rear wings with wheel arch extensions, side skirts, doors and rear spoiler
Front suspension double unequal wishbones with coil springs, Bilstein telescopic gas shock absorbers and anti-roll bar
Rear suspension live axle with 4 longitudinal links, panhard rod, coil springs and Bilstein telescopic gas shock absorbers.
Steering system rack and pinion 2.7 turns lock to lock
Brakes front ventilated disks 271/279/289mm diameter with 2 or 4 piston calipers, rear ventilated disks 271/277mm diameter with 2 or 4 piston calipers, cable handbrake. Dual circuit with servo, adjustable ratio split front to rear
length: 4475 mm (176.2 in) width: 1687 mm (66.4 in) height: 1320 mm (52.0 in)
wheelbase: 2518 mm (99.1 in) front track: 1384 mm (54.5 in) rear track: 1375 mm (54.1 in)
Rims – tires 5″~8″ x 14″~15″
  • Michelin TRX
  • 195/60VR14
  • 205/50 R14
  • 205/50VR15
  • 225/50VR15
Dry/Unladen Weight 980~1000 kg (2160~2200 lb)
Weight/power 3.6 kg/HP (7.9 lb/HP)
Fuel tank 110 lt


Opel Manta B400.jpg
Opel Manta B 400 – Homologation Version

The Manta B 400, albeit it shares the “400” moniker with its sister car, the Ascona, was actually produced at 245 units. This can be explained since only 200 cars needed to be built for Group B homologation (it was 400 for Group 4). The “400” name most likely carried over to retain a sense of continuity with the Ascona.


The homologation version of the Manta B 400 had most of the technical features of the rally car but with a luxury interior. The wide arch body kit and decals were optional items fitted out of factory by German tuner Irmscher. The car was very pricey and made Opel fans rage with envy. As such, the company spawned lesser iterations with the likes of the i400/i200, both which strongly resembled the top of the line Manta GSi mainstream production model but with the option to add the B 400’s exterior appearance.



Class Sports Homologation number: B-237 (click to see papers)
Years produced 1982~1983 (245) Assembly: Germany
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
  • natural / normal
  • Bosch L Jetronic
Ignition electronic, firing order 1-3-4-2
Cooling system water-cooled
Lubrication system N/A N/A
Type rear-wheel drive 5-speed gearbox
Gearbox ratios N/A N/A
Differential ratio N/A N/A
Clutch dry – single plate
Type steel monocoque 2 door sedan chassis. Optional body kit consisting of; Irmscher front & rear wheel arch extensions, side skirts, three-piece rear spoiler, and twin headlamps (ABS plastic)
Front suspension double unequal wishbones with coil springs, Bilstein gas shock absorbers and anti-roll bar
Rear suspension live axle, coil springs and Bilstein gas shock absorbers.
Steering system rack and pinion N/A
Brakes ventilated discs N/A
Dimensions (with optional body kit)
length: 4475 mm (176.2 in) width: 1687 mm (66.4 in) height: 1320 mm (52.0 in)
wheelbase: 2518 mm (99.1 in) front track: 1384 mm (54.5 in) rear track: 1375 mm (54.1 in)
Rims – tires
  • 6 x 14
  • 8 x 15 (optional)
  • FRONT: 195/60 VR 14 – 225/50 VR 15 (optional)
  • REAR: 195/60 VR 14 – 225/50 VR 15 (optional)
Curb Weight 1095 kg (2415 lb)
Weight/power 7.6 kg/HP (16.8 lb/HP)
Fuel tank N/A


From the January 1982 issue of Motor Sport Magazine (spell-checked & corrected)

Opel Manta 400 – Civilised homologation

ANYONE interested in manufacturers’ “homologation specials,” the road-going vehicles which allow a car manufacturer the most competitive possible specification for international competition, must have been let with a slightly sour taste from the sixties and seventies. For road testing journalist there was many disappointments, but for the buying public there were frequent disasters that have made it harder and harder to sell such cars. The 1982 FISA regulations insist on manufacturers producing 200 of the basic vehicle they want to homologate in Group B, the category from which outright international rally winners will almost always come.

The worst offenders in the homologation special game have been the British. Not that they cheat more than the rest, just that the cars were often too uncivilised and too unreliable to drive on the road. Our motto seems to have been “make as few as possible as nastily as possible, and hope nobody sees…”. Recent examples of the art have been better — Vauxhall and Talbot made genuine efforts to produce roadworthy cars from their Chevette HS2300 and 2.2-litre Sunbeam Lotus models, but too often the cars have been too rowdy and generally uncivilised to act as anything more than a competition base: and then you would be better off building from a basic body in most cases. Overseas homologation specials have been getting better. The Renault 5 Turbo and the Audi quattro are both genuinely advanced vehicles that give perfectly adequate everyday performance with proper warranty and service support in their countries of origin. The Renault is obviously the less versatile of the two in terms of accommodation and so on, but looked at as a sports car, two-seater, it achieves a convincing road-going role.

Yet there is a manufacturer planning to move into the four-wheel drive turbocharged, mid-engine exotica world of Group B with an old formula. The Group B Opel Manta 400 carries over the same front-mounted 16-valve engine and coil sprung, Panhard rod, live rear axle as featured on the Ascona 400 of 1979. Even though the running gear is no similar (four-wheel disc brakes — vented at the front, coil springs, Bilstein gas dampers, the same 144 horsepower engine) the Manta feels totally different to the Ascona. To explore these changes I took one of six pre-production Manta 400s out recover the recent RAC Rally, much of our 1,000 + miles over the same route I had used to tents RHD Ascona 400 last year.

Externally the two-door Manta body adds wheel arch extensions in ABS plastic compared to Ascona, but loses the front wing strakes that descended to Opel via BMW’s CSL. The Manta continues with the garish side stripes and the top half of the 400 symbol (400 was originally the number of Asconas that had to be made for homologation). Plastic wheel arch extensions and large spoilers front and rear are the work of West German specialists Irmscher. Ronal alloy wheels continue as before, but the five spoke design is 8×15 102 rather than the Ascona‘s 65 and carried enormous Pirelli P7 radials of 225/50 VR section, instead of the rather badly abused P6s I tried in 1980. Inside, LHD and a 220 kph speedometer confronted us. Instrumentation continues to be comprehensive and like that of the previous topline Manta — the 110 bhp injected E. That means a 7,000 rpm tachometer (redline around 6,200 rpm, 8 to 16 volt dial, matching water temperature, oil pressure (0-5 bar) and fuel tank contents minor instrumentation.

As before, the seats carry the Opel logo prominently and repeatedly, but as seats these slim Recaro units proved to have effective location and high levels of comfort even when the suspension was being jolted through Kielder forest. The most welcome change inside, compared to the Ascona, was to find a five-speed gearbox nestling to hand in place of the previous four-speed. Unfortunately it had the rather wide ratios of the Monza-Senator range, but the geared up, indirect, overdrive fifth made an enormous difference to our fuel consumption. Last year we were struggling to get 20 mpg. This time our average was 23.5 mpg, the worst figure 19.5 mpg when disporting the car through a foggy and muddy private “stage” at speeds up to 85 mph The best recorded mpg was 27.9 on a mainly legal motorway run to the Lake District from the Midlands.

Such consumption reflects how hard European manufacturers have been working to extract efficiency from performance cars as well as the ostensible economy cars. Look also at the Granada and BMW 2.8s, now on the right side of 23 mpg too, even driven hard. It seems more readily available than in the Ascona, with a lot less wind noise in evidence at any speed up to this point. Then a coupe window is likely to stand proud of its sill and provide audible warning that the car is heading for double the British speed limit.

Though 2.4-litres from four cylinders was thought large when Opel produced their Cosworth-aided four-valve per cylinder unit in 1979, current thinking from Porsche (944) and the 230E Mercedes models show that “big fours” have a lot more life left in a fuel economy era. In fact it looks as though that arch six cylinder supporter, BMW, may also be forced to follow along this road in the future, primarily looking for low speed torque, low unit weight and outstanding mpg.

The Opel alloy-headed four measures 2410 cc (95 mm by 85 mm) and carries Bosch L-Jetronic fuel injection to feed its 9.7:1 compression ratio and judging by the occasional run-on five star would not be unacceptable to Opel engineers. The twin overhead camshafts are chain driven, the crankshaft is supported by five main bearings and there are eight counterbalance weights.

From the driver’s seat peak power appears to drop very sharply over 5,500 rpm, the maximum is placed at 5,200 and amounts to 144 bhp, or one horsepower more than BMW’s 2.3-litre six as used in the 323i. Look at the torque of the Opel and the BMW and you see the real difference character: the Opel offers 155 lb-ft torque at 3,800 rpm, while the BMW’s 115 cc less provides 140 lb-ft at 4,500 rpm. A single plate, nine inch diameter clutch transmits the Manta’s power to the Getrag Monza specification five speed. The ratios? First, 3.822; second, 2.202; third, 1.383; fourth, direct; fifth 0.872. The final drive ratio for our car was a 3.18;1 and this provides the rpm. capability of 130 continued mph in top gear though the most we saw indicated was around 120 mph.

We could fairly say that the Manta had been driven through the full gamut of weather and mad conditions by the clew of our four day, two night sojourn in England, Wales and Southern Scotland. The accent was on driving pleasure over challenging B-roads, or those of lesser status down to forestry tracks.

I am prejudiced against large four-cylinder engines. I like a motor that will rev smoothly and emit quality noises of appreciation simultaneously: in mass production terms Alfa’s GTV injected six represents a high point in my estimation.

Yet the Opel does an admirable job of providing real overtaking punch — I can believe the maker’s claim of 0-60 mph in little more than 7 seconds — and reasonable economy. That would be enough to praise, if it was not for the fact that the four provides a constant stream of torque between 2,000 and 5,000 rpm. This allows pretty well any gear below fourth to provide genuine pulling power when the road is unexpectedly clear ahead, or when a corner tightens after a brow. Inject the stiffly sprung chassis and sporting Bilstein damping and you have a car that is very hard to catch cross-country, whether the going be A or B-class. Long fast corners see the 0.1 settle swiftly into a steady posture that would see the 2.10 Capri shuffling restlessly on its single leaf rear springs. On slower corners you notice that even the heaviest braking fails to lock a front wheel (a rarity amongst 1981-82 European mass production cars with their braking bias set lineally forward and that the cut-wilt turn-in with the kind of breathtaking precision that should be right with such wide wheels and pedigree Pirellis.

Very few corners demand first gear. This is fortunate for second that has a job of providing much over 55 mph, so you tend to rip third’s enormous range between 45 and fourth the equivalent of 100 to 110 mph. A constant indicated 100 mph at 4,000 rpm would be the natural gait in Germany but a steady 75 mph and 3,000 revs, is a pace the British police seem happiest at. If necessary fourth gear can be used smoothly from 1,500 rpm, below that the engine pulls well but there’s a lot of vibration within.

Some Opel dealers commented how much more precise and civilised the Manta is compared to the Ascona 400. The handling improvement seems entirely due to those P7s. Their only drawbacks being that standing water makes the car slide just like a race saloon would upon slicks. Pirelli’s stiff, low-profile, construction naturally does nothing to help a live-axle car skip over bumps, without the occasional jarring thump reaching through the seat back. Naturally the tyres tend also to follow any ridges in the road.

Opel sporting manager in Germany, Tony Fall, is well aware that a little more work is needed to refine the suspension: “I think it would be less twitchy with some of the production castor angle removed”. he opined – but I think the slightly offset, and wider, rear track has helped the handling a lot. The main benefit of the Manta 400 over Ascona, for us on the competitions side, will be that of weight. With more plastic parts homologated and the Manta body, we should be able to get it at 980 kg, which is considerably less than most of our rivals”. The Manta inspected first to be seen internationally on the Acropolis Rally and on the Scottish home International in June. Russelsheim plans to run two cars in the World Championship next year for 1980 World Champion Walter Röhrl who won the Acropolis for Opel in 1974 and will be an Ascona and subsequent Manta 400 for Jimmy McRae, 1981 British Champion, and it is to be hoped he will also get some overseas Championship chances too. Unconfirmed at press time was the expectation that Opel will also run a prototype Manta in Britain with the Ferguson four-wheel drive system, running within the national rally championship.

As a road car the Manta 400 has to be judged in the light of its price. There is evidence that Opel have taken a careful look at Audi quattro marketing and decided they must not be too close to the four-wheel drive, turbocharged wunderwagen. In Germany the Manta 400 will cost approximately £9,500 and in the UK – probably a little over £12,000 so not too close to the Audi”. I was told. Although I enjoyed the Manta and was very impressed with its handling, seating comfort and mpg performance balance, there is no way I could ever see myself parting with that sort of money for this car unless I either lived in Ireland, or the Isle of Man, where it would be most enjoyable in everyday use or I was a keen road rally competitor who wanted an interesting dual purpose vehicle.

Sales are expected to start in Spring of 1982 and, unlike the quattro and the Renault 5 Turbo at the time of writing, RHD will be available from the factory.

— J.W.

SOURCE: (C) Motor Sport Magazine – January 1982 (used under permission)

To read more about Group B related articles on Motor Sport Magazine please visit their archives: http://www.motorsportmagazine.com/archive



(free delivery worldwide!)

AWIN Affiliates Program – by purchasing books with the links provided here you are also helping to support the Rally Group B Shrine!*

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

Gruppe B Gruppe B – Aufstieg und Fall der Rallye-Monster (German)

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

Gruppe 4 Gruppe 4 – Das Jahrzehnt der Heckschleudern (German)

Cosworth Cosworth- The Search for Power

(C) Rally car article, homologation car, & specifications 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
  • Eifel Rallye Festival Pictures used under permission – McKlein Publishing

Community Website: