ROAD AND TRAIL TEST Opel Manta 400 Civilised homologation
ANYONE mteresteed in manufacturers’ “homologation specials,” the road-going vehicles which allow a car manufacturer the most
competitive possible specification for international competition, must have been lett with a slightly sour taste from the sixties and seventies. Fees road testing journalist there were many disappbintments, but for the buying public there were frequent disasters that have made it harder and harder to sell such cars.
The 1982 FIA 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 — Vatuchall 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 uncivilised to act as anything more than a cornpetiton 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
Quatuo are both genuinely advanced vehicles that give perfectly adequate everyday performance with proper warranty and service support in their countrien 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 Ancona 400 of 1979. Even though the running gear is no similar (four-wheel disc braes — 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 Ancona, but loses the front wing strakcs 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
Ascona, was to find a five-speed gearbox nestling to hand in place of the previous four-speed. Unfortunatly 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.
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 measutes 2,410 cc. (95 mm. by 85 mm.) and carries Bosch L-Jctronic 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 th 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 oft our car was a 3.18;1 and this provides the r.p.m. capability of 130 conttnued overleaf —
m.p.h. in top. 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 preiudiced 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 antgear 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 Bilatein damping and you have a car that is very hard to catch crom-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 ht lock a front wheel (a rarity amongst 1981-82 European mass production cars with their braking bias set linnly 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 has a Job providing much over 55 m.p.h.. so you tend to rid third, enormuus range between 45 and m pit to coprwithm,tstci,rttet-itig.tnd,,t-ertitktnntoskv.ls
fourth the equivalent of 100 to 110 mph. seems more readily available than in 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.
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 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 iust 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 jarrisg thump reaching through the seat back. Naturally the tyms 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, fur us on the competitions side, will be that of weight. With more plastic parts homologated and the Manta body. we should be able It wmPcla at 980 kg.. which is considerably less than most of uur 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 Rolirl who won the Acropolis lotOpel in 1974: and 1980 RAC Rally winner Ilene, ‘foie… recruited frt. Talbot Also in Rothmans colours
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 thr 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 unles 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, RHO will be available from the facto, for this eye catching 0,1. — J.W.