Background

This created a golden era in motor rallying history - Audi, Lancia, Peugoet, Ford, Citroen and Austin Rover created many super rally cars to compete in World Rally Championship, all with at least 400 horsepower, lightweight Kevlar body and most of them were mid-engined and 4-wheel drive also. Recalling that period, motor rally enthusiasts always regard that as the best moment of their life. WRC had never been as exciting as that period.

What a pity the Group B ended in misery. In 1986 season, series of accidents involving spectators as well as led to the death of Lancia's top driver Henri Toivonen and navigator Sergio Cresto happened. Group B was accused of being too powerful and too light to be controllable. As a result, FIA axed it after that season.

WRC (1983-86)

The Road Cars

• Audi Quattro Sport
• Ford RS200
• Lancia 037
• Lancia Delta S4
• Peugeot 205 T16
• Rover Metro 6R4
• Renault R5 Turbo

The 2133 c.c. all-alloy 5-cylinder unit had 4-valve head plus a big turbocharger. Maximum power in race car reached 500 hp, while the road car still managed to put out 300 hp. No wonder R&T recorded 3.6 sec for 0-60 mph and 11.8 sec for quarter mile for the race version, both were faster than Peugeot 205T16, Ford RS200 and Lancia 037.

The chassis was as conservative as the normal Quattro road car - steel monocoque was retained, front-engined configuration remained unchanged. To reduce weight and enhance nimbleness, wheelbase was shortened by a massive 12.6 inches. This led to the very strange-looking appearance - it simply looked like a Quattro coupe with the center section chopped away. Short wheelbase married with long overhangs in front and tail, what a contrast to today's design philosophy !

The body was made of mostly Kevlar, some aluminium and glass-fiber, just like other Group B cars. Also like other Group B cars, the Quattro Sport road car was very difficult to drive. It was very raw, too.

RS200 was approved by FIA in 1983, but the required 200 road cars were produced in as late as 1985 to 86. In terms of technology involved, it was quite advanced - spaceframe chassis, mid-mounted engine, Kelvar body for race car or honeycomb-structured glass-fibre body panels for the road car, 4-wheel drive, twin absorbers in each corner ...

The engine was a 1.8-litre 16V turbocharged four-cylinder, just like Delta S4 and 205 T16. In road trim it output 250 hp, good enough to achieve 6 and a half seconds for 0-60 mph. According to the comment by Autocar, the driving environment was noisy and hot, the high-boost turbocharged engine was laggy (just like other Group B cars), all controls were taut. In fact, Group B cars were never as fun to drive as other pure road cars, because they had to sacrifice something to ensure competitiveness in rallying. They were just bought for participating racing events, or simply for their rarity, in the collector's point of view.

In racing, RS200 was not very successful, despite it won its debut race in a less competitive event. Before Group B was axed in 1987, it raced for 2 seasons and was never as competitive as the dominating cars like Lancia Delta S4 and Peugeot 205 T16.

Although Lancia already had a mid-engined race car called "037" (or "Monte Carlo" for road version), this car was found outpowered (only 325hp, compared with 440hp of Peugoet and 500hp of Audi) and outhandled by rivals (2WD only, unlike Audi and Peugeot's 4WD). Therefore Lancia had to develop the Delta S4 as a replacement.

Like contemporary rivals, Delta S4 was styled and named to promote the mass-production Delta. In fact, under the skin it was a clean sheet design. Being disagreed with Audi Quattro Sport's front-engined theory, it adopted the more popular mid-engined layout. The engine was longitudinally mounted behind the front seats, directly driving the viscous-coupling LSD which transfered 30% torque to front wheels and 70% to the rear. At each of the corners of the steel tubular space frame chassis, double wishbones and twin absorbers were employed as suspensions. All these were covered by a glass-fibre / epoxy resin composite body. (Kevlar for race car)

While its 4WD system was not as advanced as Peugeot 205T16's (which had variable torque split between front and rear axles), its engine was by far advancer. As I know, it was the only car ever employed turbocharger and supercharger simultaneously.

Turbocharger is generally regarded as the most efficient means of forced induction, but it requires higher rev (hence a lot of exhaust gas) to operate. The result is poor low-speed power and the presense of turbo lag. On the contrary, supercharger performs strongly and instantly right from idle, but it is rahter inefficient in high rpm. For a rally car, a flat torque curve over a wide range of rpm is always very crucial, since rally car has to brake to very slow in tight corners and then accelerate to near top speed in 10 seconds. Therefore Lancia spent a lot money with Abarth to develop a system combining both turbocharger and supercharger to get a perfect output. It employed twin intercoolers, one for the turbo and one for the supercharger. The supercharger worked at low speed. Once the turbo cut in, a bypass valve relieved the pressure from the supercharger so that energy efficiency was be lifted.

This system was not only complex, but also faced great difficulties during development. The biggest problem was the transition between supercharging and turbocharging, since a short zero-boost period existed. However, after further developement, this problem was eventually solved.

As a result, the 1.8-litre engine had an outstanding power of 250 hp and a healthy 214 lbft of torque, while the rally car had at least 470 hp and 333 lbft.

Like other Group B cars, only 200 units of road version were made to fulfill the minimum requirement for homologation.

In WRC, Delta S4 experienced a dramatic fate. It won its debut race, then continued to dominate the following races and was leading both the driver and manufacturer championship standings. Such excellent results amazed everyone, since it was a completely new car. In 1986, Tour de Corse (Corsica Rally), leading driver Henri Toivonen and navigator Sergio Cresto crashed in their S4 and both were killed. The team lost its momentum and eventually handed the title to Peugeot. This accident led to the rethink of Group B cars. Races went on but finally FIA annouced the termination of Group B, because it was too powerful and dangerous. Therefore, Delta S4 became the most outstanding rally car in history that did not won world title.

Patrick Head, who is now the technical director of the F1 team, was responsible for the development program. Rover's old V8 was chopped to become a V6, accompanied with many modifications of course, including 24 valves cylinder heads and Cosworth racing pistons. The result was a 3-litre engine developing 250 hp in street form and 410 hp in racing trim.

Like other great rivals, the engine was placed in the middle of the car, driving all 4 wheels, with radiator located behind the big air intake beside the doors. Massive front and rear air foils gave it a distinctive look.

We have no idea how it worked on road. However, in rallying, its best result was just a third place in RAC 1986, which was its debut race. This doesn't mean the non-turbo experiment failed. In fact, without much financial backing, Metro 6R4 had no reason to succeed.

The 1.8-litre 16 valves turbocharged four generated up to 440 hp in race form but only 195 hp in road trim - in fact, unlike Audi and Ford, Peugeot (as well as Lancia S4) had no intention to fulfill the customers' expectation. All it wanted was to win the WRC and spend as little to the road car development as possible.

However, the road car still (had to) shared most of the advanced technology with the race car, including the unique center differential which enable on-board selection of different torque slit ratio between front and rear axle. Driver might select the most suitable setting for different kinds of road.

The earliest mid-engined R5 Turbo was unveiled in 1980. It certainly catched some attention, but was never competitive in motor rallying. Perhaps Renault's biggest bet was still in F1. The second generation appeared in1984, whose performance tested by Autocar showed pretty big turbo lag at low speed.