Volvo races anti-slip
The Estoril circuit in Portugal has its share of slow corners, where racing drivers need to feed the throttle to get their cars round cleanly without losing time. Mauro Baldi and Per-Gunnar Andersson could ignore the conventional rules when driving their 240 Turbo in the final round of the Touring Car Championship, however, on their way fifth place overall. With Electronic Traction Control the rear wheels couldn’t spin, and the car wouldn’t slide.
“I found the system particularly effective when the tyres were cold” said Baldi. “I started the race with the ETC switched off but then I switched it on and immediately I went faster.” With telemetry, engineer Lars Sandberg in the Volvo pit could see on computer print-out when the Pirellis had hit oil but within four milli-seconds the turbo boost had been lowered, and the fuel flow reduced, preventing any loss of traction. “If it had rained I think we would have won that race,” said Sandberg next day.
On Monday it was our turn to sample the ETC-equipped Volvo, the nearest a journalist can get to a foolproof racing car! Despite the sedate appearance of the 240 Turbo it’s not far off the class minimum weight, at 1,065kg, and the fuel/water injected 2.1 litre engine develops up to 350 bhp. It’s not in the same class as Formula 1 and Group C cars obviously, but the power-to-weight ratio is still ample to get a leading TCC contender into big trouble if driven badly.
Volvo has seen the chequered flag five times in the 1986 season though two victories have been taken away for alleged irregularities in fuel blend and tank capacity (both still disputed by Bo Wikas, Volvo’s Motorsport manager, though the rulings are accepted). It has not been such a successful season as 1985, when Volvo notched up seven outright wins enabling Thomas Lindstrom and Gianfranco Brancatelli to share the Drivers’ Championship, but competition has increased from BMW, Ford, Rover and Holden, while the Belgian RAS team which took over from Eggenberger at the start of the season needed time to acclimatise to the new level. Two weeks after Estoril, Volvo’s management made the decision to withdraw its official support for racing, and RAS will compete with another make in 1987, an announcement which came as a shock to those inside the company as well as to outsiders. The underlying reason may be general dissatisfaction with the way that FISA is running the sport, changing regulations at will and militating against turbochargers.
Though it may never do so again, Electronic Traction Control proved itself at Estoril: Baldi and Andersson drove the only Volvo that ran trouble-free, and finished in fifth place, only one lap behind the winning Ford Sierra and three Rovers, despite a last-minute engine change to a unit that hadn’t been adjusted for maximum performance. The value of ETC in low-grip conditions could be worth more than a substantial increase in power, enabling the engine, the chassis and the tyres to work at maximum efficiency.
The driver’s job is certainly made easier by a system which prevents time-wasting slides, but this is only one facet of the racing Volvo. It also has a simplified dashboard with merely one instrument to check (the rev-counter) and an array of little lamps that should all be green when the various systems are functioning properly. No distractions there for the driver, who can give total commitment to the job in hand.
The racing version of ETC is a direct development from the passenger car system announced by Volvo in 1985, an electronic alternative to four-wheel drive. The speed of the rear wheels relative to the front wheels is monitored by an ABS-type computer, and any differential immediately reduces the boost pressure from 1.4 bar, then reduces the fuel supply to the centre pair of cylinders.
It takes time to gain the courage to use the system properly, since it defies experience to floor the throttle in the early stages of a slow corner, when the slick D3 compound Pirellis are howling. In fact, when exiting the “chicane” corner preceding the big right-hander leading to the main straight, the rear end did lurch and the inside rear wheel would spin momentarily. Not what I expected! In the pits Lars Sandberg realised that the ETC control knob, giving a range of slip on a 1 to 6 scale, was giving the minimum assistance.
A second run, with the ETC setting on 1, proved easier and was four seconds a lap quicker. I was of course learning the track and getting used to the car, so quicker times should not have been difficult to achieve, but at the same time the Volvo felt more controllable and inspired greater confidence.
Earlier, some laps in the passenger seat with Johnny Cecotto driving had been a useful introduction, for the Venezuelan, who led 11 of the 14 races this year, had taken the corners extremely aggressively. The capabilities of the car were clear, while those of a less experienced driver were not!
The Volvo’s acceleration is impressive, though not a mighty shove in the Recaro seat-back, and deceleration is marked by a series of grenade explosions in the straight through exhaust under the passenger’s door.
On the straight the 240 Turbo felt almost leisurely, climbing to 7,400 rpm in fifth gear, computed at 230 km/h. Cecotto was nearing the 100 metre board when he applied the AP brakes savagely, but I would lose time braking at 200 metres, and that felt borderline.
My first dozen laps, with a burly mechanic in the passenger’s seat, were purely exploratory. Partly due to the noise level, partly to the willingness of the four-cylinder engine to rev, it felt low-geared and it made no apparent difference to take the corners in second or third gears. With confidence building I could begin to attack the corners, but the Volvo neither understeered nor oversteered, remaining faithfully on line. A time of 2 min 04 sec hadn’t involved any risk at all, though the hint of oversteer urged discretion.
Even a journalist, best in control of an electronic typewriter, experiences the baser instincts of a racing driver at times like this. Given half an hour to relax the logic goes to work, reassured by Sandberg’s certainty that on the “1” setting the rear end would behave itself. I could, I was sure, brake later at certain points, take a higher gear in turns 1 and 10, and reach the straight at a higher speed.
Six more laps in the Volvo proved these theories correct. Taking the last turn in third gear instead of second avoided a shift before the car was straight, and found an extra 300 rpm at the timing line. . . 7,100 rpm in fifth, 220 km/h. The first turn is fast, easy in third, and even the tighter corners could be taken “flat” in second. The experience of going straight from the brake pedal to full throttle, entering the turns, was uncanny, but was surely improving the lap speed without running any risks.
The fifth turn is a right-hand kink, flat in third with the Volvo wafting a metre to the left after hitting a bump, then there’s a short straight behind the pits to Estoril’s most interesting corner, a big double-apex turn to the left. This inevitably involved a shift from second to third before the car was straight but the remarkably precise, light action gearbox allows this without destabilising the car. And the chicane, later, could now be taken at full throttle in second, the ultimate test of Electronic Traction Control.
A time of 1 min 58 sec would be history in a race, eight seconds off Baldi’s best . . a lifetime in racing parlance, but that it was achieved by one who is not a racing driver, lacking previous experience of the car or the circuit, is a testimony to the Volvo’s good manners, its traction control system and the Pirelli tyres.
All down to development
It took one season, in 1983, to develop the Volvo 240 Turbo to a fully competitive pitch. It won races in 1984 against Jaguars as well as BMWs and Rovers, and in 1985 it won half the races it contested. “We have worked on the engine, the chassis, the brakes and the tyres, and all of these are making their contribution” says Bo Wikas. When Thomas Lindstrom and Volvo engineer Robert Kvist set out in 1983 they had a car that weighed 1,100 kg and developed 270 bhp (then, as now, the engine was equipped with water injection); now the 240 Turbo is 35 kg lighter and develops 340-350 bhp, with Volvo’s own complex electronics regulating boost pressure, water injection, ignition timing and rear-wheel slip. If, for instance, the water temperature rises unacceptably the boost is automatically lowered, and any cylinder knock is immediately controlled by retarding the ignition on that plug. And those dancing lights across the dashboard tell many tales but so long as they’re all green the driver has nothing to worry about: boost pressure, water and oil temperatures, fuel level and the water injection system are all within pre-set parameters.
Pirelli equips about 80% of the Touring Car Championship teams, all the leading makes except Rover, and the Milanese company has co-operated well with the Gothenburg engineers. The Volvos race on 16-inch diameter wheels with a maximum permitted 11-inch width of tyre, though next season the Volvos would have run on 17-inch diameter wheels with the same tyre rolling circumference. With lower, stiffer sidewalls the car’s stability is improved, and turn-in is better too. contributing vital tenths of a second to lap performance.
Aramids (the generic term for fibres known as Kevlar in DuPont’s patent dictionary) are now widely used in race tyre construction, as Mario Mezzanotte, Pirelli’s head of race tyre development, explains. “We are retiring from Formula 1 at the top. Our tyres played significant part in Gerhard Berger’s victory in Mexico, but now we have reached all our targets in research and development of very high performance tyres, and are ready to transfer this knowledge to Group A, rallies and normal production.”
The tyres supplied to the Benetton and Brabham Formula 1 teams were unusual in that the qualifying sets could be “cleaned” and used again, to advantage, while the race tyres were able to go the full distance at a competitive speed due, says Mezzanotte, to superior techniques in construction, compounding and curing. Although speeds in Group A racing are lower, the cars are heavier, and higher mechanical stresses are involved. Nylon carcasses are featured in the tyres supplied to the leading TCC teams with one belt of steel ply (better in compression) and one in aramids (better intrusion); as a result the tyres are 10% lighter and run cooler, with better consistency, allowing the use of softer compounds for higher lap speeds. And, transferring this new-found experience to the production line, P7R tyres with aramid belts are supplied to Ferrari, Maserati, Aston Martin, de Tomaso, Lamborghini and Bentley, an impressive list of customers.
For Pirelli’s rally customers the major breakthrough has been in run-flat tyres capable of getting the crew to the end of a stage even with a deflation; future developments include tyres specifically designed for four-wheel drive cars, with dual compounds (harder on the outside) and asymmetrical tread patterns.
Both Volvo and Pirelli have been able to demonstrate that racing forces the pace of development. Bo Wikas and Mario Mezzanotte said, independently, that race programmes improve both the products and the levels of expertise of the staff involved, managers needing to make key decisions without delay.
Now, sadly, Volvo’s support of the RAS team is to be discontinued and the Belgians will look elsewhere for their effort in 1987, though the Swedish company will continue to support national efforts in Germany, Portugal and Australia.
Volvo’s driving team in 1986 has included Thomas Lindstrom, “father” of the race programme, Ulf Granberg, Anders Olofsson, Per-Gunnar Andersson and the two quick foreigners, Johnny Cecotto and Mauro Baldi, all of whom have enjoyed a competitive and accident-free season. In terms of results it was a little less satisfactory, maybe, than 1985, but that is the least of Volvo’s reasons for deciding to withdraw from front-line competition.
As it turned out our laps of Estoril in the factory-supported RAS Volvo 240 Turbo were the last to be run by a team car, and the 1987 World Touring Car Championship will be poorer without the Swedish manufacturer, especially since Rover is also out of the running. And, unless a leading private team approaches Volvo, the true value of the ETC system in race conditions may never be appreciated. MLC