Opel Manta B400 + Homologation Version

opel_manta_400_rally_car.jpg
Opel Manta B 400 Rally Car

In 1983, as part of GM’s continued international motorsport branding effort, Opel made the transition into Group B from the Ascona B 400 with its sister car, the Manta B 400. Since 1981, both cars had been developed simultaneously for this purpose. At the time, since the Ascona gave the Audi quattro a very good fight in 1982, there was high hopes that the new and improved car sporting the classic rear wheel drive layout would yet remain competitive for a while longer.

opel400.jpg

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

Opel-Manta_400_R.jpg

In its inaugural 1983 WRC season, the Manta could only watch the fight between Audi and Lancia without being able to truly impose itself. In 1984, overwhelmed by the fierce competition, the car fell further down the leader-boards. By then, Opel’s international efforts were basically abandoned. However, the Manta proved to be a major contender in national rallies (especially in the British Rally Championship) where the level of competition was lower and featuring similar competition.

ANECDOTE

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 prototype of the Manta B 400 be built. The project was ultimately cancelled. More information about that car can be found by clicking here! Another interesting project was considered at the same time that the Manta 400 was being finalized: the Opel Kadett 400.

SPECIFICATIONS

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

  • start: March 1st 1983
  • end: December 31st 1989
Engine
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
Aspiration
  • 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
Transmission
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
Chassis-body
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
Dimensions
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

HOMOLOGATION VERSION SUMMARY

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.

manta-b-400.jpg

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.

Opel_Manta_b400.jpg

SPECIFICATIONS

Class Sports RWD 2-door sedan
Years produced 1982~1983 (245) 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, 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
  • 6J 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

ROAD CAR TEST ARTICLE

From the January 1982 issue of MotorSport 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. Fees 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 uncivilized 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 H52300 and 2.2-litre Sunbeam Lotus models, but too often the cars have been too rowdy and generally uncivilized 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 81×15 102 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 k.p.h. speedometer confronted us. Instrumentation continues to be comprehensive and like that of the previous topline Manta — the 110 b.h.p. injected E. That means a 7,000 r.p.m. tachometer (redline around 6,2001, 8 to 16 volt minor 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 foal consumption. Last year we were struggling to get 20 m.p.g. This time our average was 23.5 m.p.g., the worst figure 19.5 m.p.g. when disporting the car through a foggy and muddy private “stage” at speeds up to 85 m.p.h. The best recorded m.p.g. 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 m.p.g. 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 m.p.g.

The Opel alloy-headed four measures 2,410 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 r.p.m., the maximum is placed at 5,200 and amounts to 144 b.h.p., 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 r.p.m., while the BMW’s 115 c.c. less provides 140 lb. ft. at 4,500 r.p.m. 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 r.p.m. capability of 130 continued m.p.h. in top gear though the most we saw indicated was around 120 m.p.h.

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 m.p.h. 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 r.p.m. 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 he 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 m.p.h., so you tend to rip third’s enormous range between 45 and fourth the equivalent of 100 to 110 mph. A constant indicated 100 m.p.h. at 4.000 r.p.m. would be the natural gait in Germany but a steady 75 m.p.h. and 3.000 revs, is a pace the British police seem happiest at. If necessary fourth gear can be used smoothly from 1,500 r.p.m., below that the engine pulls well but there’s a lot of vibration within.

Some Opel dealers commented how much more precise and civilized 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 hi 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 plan to run two cars in the World Championship next sear for 1980 World Champion Walter Rohrl 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 M the UK -probably a little over E12,000 not too close to the Audi”. I was told. Although I enjoyed the Manta and was very impressed with its handling, seating comfort and m.p.g. 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 at the time of writing, RHD will be available from the factory, for this eye catching 0,1. — J.W.

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

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


 

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