Rally Review -- Tour of Corsica , June 1991
Sainz on Corse
Almost since the need to drive fast began to be an essential part of rallying, those responsible for preparing cars have had two major objectives; speed and reliability. Most other claims on the attention of car builders, for example, handling, flexibility and the need to have components fitted in such a way that they can be replaced quickly at the roadside, evolve from one of these.
But hand in hand with the requirement to make a car travel as fast as possible is that of giving it the ability to stop. The faster it goes, the more difficult it is to slow it down. Weight is also part of the equation, as most schoolboys will know, for momentum is the product of mass and velocity, and it is momentum, rather than speed alone, which is what must be reduced by braking action. Equally, therefore, the heavier a car, the more difficult it is to slow it down.
For normal road use, the brake assemblies on production cars are perfectly adequate, but if such cars were driven fast on very twisty roads, demanding hard braking before each corner, the chances are that brake efficiency would diminish, or “fade”. The reason? Heat!
The principle behind braking is friction. Give the wheels more friction to work against as they revolve, and they will slow down. But friction also generates heat, which in turn causes brake fade. In severe cases, brake pads themselves can burn, hydraulic fluid can boil, and discs can become so red hot that they can be seen glowing brightly in the dark.
Speed alone does not cause brakes to deteriorate. Long straights separated by occasional corners will seldom produce brake fade because, although the brakes are applied hard, they are not applied often. It takes a lot of effort to slow a car from 120 mph to 20 mph using the shortest possible braking distance, but provided it does not have to be done too often little harm will have been done to the braking efficiency. But if a car has to be alternately accelerated and slowed every twenty-five yards or so, then the effects of friction-produced heat will soon be noticed.
It is down to the team to decide on means to prevent overheating, though usually in collaboration with the brake manufacturer. Even the fastest, best handling car, fitted with the best tyres, will fail to achieve success if its brakes fade due to overheating, and nowhere is this more evident than on the tortuous special stages of Corsica.
Every special stage consists of short bursts of fierce acceleration each followed by hard, last-minute braking for the sharp corner which inevitably follows. Brakes, therefore, have to be supremely efficient in order that drivers maintain their confidence that they will be able to slow down adequately for the next corner.
Consequently, pre-event test sessions in Corsica are devoted as much to the brakes as to other aspects of fine adjustment. It is impossible to prevent heat build-up. It is a natural product of friction and nothing can be done about it. But what can be done is to devise means of removing heat as it is produced, preventing it reaching a harmful level, and different teams had different ideas on this subject.
The simplest method is to copy that of windscreen washers, as many do in Kenya to keep shock absorbers cool. Small units consisting of reservoir, electric pump and a few jets are all that is required, plus a switch on the dashboard. Ford used such a means to cool their 14-inch AP discs and their shock absorbers, the whole lot being fed from one 5.5 gallon water tank.
Subaru also had a water cooling system, but theirs was a sealed, recirculating system, with small tank, radiator and caliper water jacket cooling each of their AP brakes, which were 14-inch, just like those of Ford. Lancia used water jets to cool their discs, which were smaller than those of Ford and Subaru, but so well ventilated that they looked as though someone had been let loose on them with a newly acquired electric drill!
Toyota also had small brake discs, limited of course by wheel size, but decided after testing that water cooling was not necessary. It seemed that pads with friction surfaces containing a ceramic compound would be enough to prevent excessive heat build-up.
Ford, Toyota, Subaru and Lancia were the main contenders in the 100-strong field of starters in Corsica, although Renault, Citroën, Peugeot, Mitsubishi and even Alfa Romeo were represented in one way or another, whilst a well-driven BMW got into the first ten.
Ford’s official line-up consisted of two four-wheel drive Sierra Cosworths for Malcolm Wilson/Nicky Grist and Francois Delecour/Anne-Chantal Pauwels. Bernard Beguin/Jean-Marc Andrié from France and Franco Cunico/Stefani Evangelisti from Italy drove privately prepared cars, similar in most respects to the works cars but having five-speed gearboxes. Wilson and Delecour each had seven available ratios.
Lancia had two Delta Integrales for Yves Loubet/Jean-Paul Chiarioni and Didier Auriol/Bernard Occelli, the former in Martini colours and the latter in those of Fina, although entered by the Jolly Club. A third car, prepared in France and backed by Fina, was driven by Bruno Saby/Daniel Grataloup.
A somewhat strange appearance was that of a Group N Delta prepared by Italy’s Astra team for Finnish lady driver Minna Sillankorva. She plans to contest the ladies’ section of the World Championship this year, but although this crown can only be awarded to a driver who has started seven events during the year, her budget did not run to driving in the Tour of Corsica. By prior arrangement, the Astra car was taken to Corsica, driven off the start line and through the first special stage, whereupon it was promptly retired.
Toyota entered two Celica GT-4s for Carlos Sainz/Luis Moya and Armin Schwarz/Arne Hertz, whilst a third appeared in Fina colours, driven by Marc Duez/lClaus Wicha. There was just one Subaru from Prodrive, backed by BP and driven by François Chatriot/Michel Perin.
A single Galant VR-4 was entered by Mitsubishi Germany for Ronald Holzer/ Klaus Wendel, two AX Sports by Citroën for Laurent Poggi/Didier Breton and Sylvan Polo/Christian Tilber, and two Group N Alfa Romeo 75s by AR France for Pierre-César Baroni/Philippe David and Christine Driano/Marie-Christine Lallement. Renault sent three unblown Group A Clios, entered in the name of Team Diac, for Jean Ragnotti/Gilles Thimonier, Philippe Bugalski/Denis Giraudet and Claude Balesi/Jean-Paul Cirindini. A Renault 5 CT was driven privately by Corsican veterans Manzagol and Monti who finished tenth overall and won the Group N category. Magaud and Doenien drove a 309 and a 205 respectively for Concessionnaires Peugeot, the French distributor.
There was a time when the French saw the Tour of Corsica as their kind of Targa Florio; not actually a race, but as near as possible to it without actually moving outside the definition of a rally. Certain road sections were declared selectifs and given time allowances which were impossible to achieve, whilst a further complication was the inclusion of special stages within some of those impossible sections, a ploy which the Alpine Rally also used.
Even ordinary road sections were tight enough, and the whole thing was virtually a road race from start to finish, only the emplacement of controls and the creation of a timetable — of sorts! — establishing it as a rally. Stopping to refuel or to change tyres almost invariably led to a penalty, and the whole thing was so fast that the police made it their practice to close almost the entire route, which made things very difficult indeed for both service crews and local residents.
Nowadays, the rally has quite a different character. Road sections are far more relaxed, rest stops are longer and more frequent, and the entire island is not brought to a complete standstill by wholesale road closures. The change has come about gradually, partly to reduce the disruption it inevitably caused, partly because of safety requirements and partly due to FISA’s standardisation requirements, one of which was to limit the length of special stages to 30 kilometres (18.64 miles).
Most of the changes remain, but following an application by the French Automobile Sport Federation, FISA this year allowed the event to run special stages which were longer than the former maximum. This year there were three stages longer than 40 kilometres, the longest being 48.09 (nearly 30 miles).
The increase in stage distance not only meant that the problem of brake cooling was rendered more acute, but gave the tyre suppliers something extra to ponder. Special stages having been limited in length, they had become accustomed to producing and supplying rally tyres which would last precisely the distance required. Now they had to last longer, so there was a general rethink on tread compounds and patterns, both by Pirelli and by Michelin. Ford and Toyota use Pirelli tyres; Lancia and Subaru use Michelins.
At one time the base of the rally used to alternate between Ajaccio in the South-West and Bastia in the North-East, but in recent years it has been kept at Ajaccio and Bastia only visited occasionally, as it was this year for a night stop. The Sunday-to-Wednesday event was divided by three night stops into four daylight legs; the first stop at Ajaccio itself; the other two at Bastia and Calvi. There were 27 special stages totalling 389 miles which, at 45% of the 860 mile total distance, represents a higher proportion than most rallies achieve. Of course, if the rally had to rely on private roads rather than sealed-off public ones as other organisers are obliged to do, the proportion would be far, far less.
Having spent some years moving around the calendar, the rally is now established as a springtime event, but even so, there is absolutely no guarantee about the weather. Indeed, if you fly over the Mediterranean and see a solitary wedge of dark cloud in an otherwise clear sky, the chances are that the cloud will be directly over Corsica. This year rain and hail punctuated the periods of sunshine, whilst the mountains were still snow-capped.
The weather can often place a limit on the usefulness of helicopters for servicing, for the route passes through mountainous terrain in which fog or low cloud can create impenetrable areas. Landing spots are not exactly plentiful either, and pilots often have to indulge in tricky manoeuvring in order to get into confined areas. We recall one pair of aircraft having to land with their main rotor-blade tips just a few feet from a wall and their tail booms overhanging a steep drop. There can even be no suitable landing spot at all, and mechanics then have to jump out of the aircraft whilst it is in the low hover.
The first day consisted of two loops from Ajaccio, the first containing one stage and the second three. Armin Schwarz was the leader at the end of the day, the young German showing that the confidence placed in him by team director Andersson was not at all misplaced. Loubet lost about ten minutes off the road when, on the third stage, his seat broke loose from its mountings and he found himself without any support at all. Citroën’s rally didn’t even progress this far, for both Poggi and Polo retired, the latter by going off the road and the former the result of a steering fault.
Malcolm Wilson had a trying day indeed, losing time firstly due to a bad tyre choice and secondly as the result of a misfire. He was also put off his stride when he encountered Baroni’s retired Alfa Romeo partially blocking the road after crashing on the third stage. But this was not all. On the way back to Ajaccio his gearbox refused to allow him full selection and, having tried repeatedly to engage the vanous ratios, he was finally left stuck in reverse. There was a mile to go, and the only way to cover that distance was backwards! He managed it, but it certainly confused everyone, officials, spectators and police. The next morning was no different, and we can recall no other occasion when a car has been reversed off the restart ramp when the flag was lowered.
Nine stages totalling 133 miles figured on the second day, and on the third both Saby and Beguin encountered cattle on the road, fortunately without mishap. Ironically, it was the same stage on which Sainz had met a non-competing car last year, an incident which had alarmed the Spanish driver considerably but which was dismissed as unimportant by FISA’s chairman during the post-rally press conference. Safety standards can obviously vary, especially when they apply to his own backyard!
Stage eight, the fourth of the day, began under a heavy sky and, as expected, the rain began even before the leader had reached the summit of the pass. The rain even turned to hail which drummed against car roofs like metal pellets and gave the road the appearance of being snow-covered. Saby spent about half a minute off the road on this one.
At nearly 30 miles, the tenth stage was the longest of the event, and it was here that Schwarz came to grief. The surface was drying, but it obviously hadn’t dried enough for the slicks which he had chosen. On the downhill part of the stage he slid wide on a corner, off the road and out of the rally. Later, on the final stage of the day, Chatriot lost some time when his Subaru’s turbocharger failed, but this was put right and he continued.
Delecour lost some seconds by spinning on the last stage of the day, but this was an isolated incident and his driving was demonstrating all the polish which he had shown in Monte Carlo. Indeed, at Bastia he and Auriol were joint leaders,19 seconds ahead of Sainz. Cunico, Duez and Wilson came next, and it says much for the potential of Ford that the leading seven included four Sierras.
Restart order is by overall position after the previous leg, but as there were two joint leaders, which of them would be first off the ramp on the Tuesday? The distinction went to Delecour on the basis that he had been fastest on the first stage of the rally. By this time, the rain and hail had stopped, the sun was shining, and the tyre men were putting away their asymmetric rain tyres in favour of slicks.
The Renault Clios had been performing remarkably well, but a few minutes lost off the road meant that Ragnotti was unable to have a scheduled, precautionary transmission change. Yes, you’ve guessed it! Little over a mile into the next stage, which happened to be one of the three long ones, he stopped with complete transmission failure and was out of the rally.
Wilson lost a minute or two when a bleed nipple loosened, causing the loss of brake hydraulic fluid, but that turned out to be the least of Ford’s worries. Not long afterwards, Delecour’s engine spluttered and stopped, a lead to the fuel pump having broken. By the time this was traced and put right, no less than 16 minutes had been lost, and the rally leader had dropped to 11th place.
As though that were not enough, Beguin’s rear suspension collapsed, and it turned out that this was due to failure of the very same joint that took almost certain victory away from Delecour on the Monte Carlo Rally. After that event, Ford had widely circulated both the cause of the failure and the revision which had been devised to prevent it, but somehow this recurrence escaped the net.
By this time, Sainz had forged ahead and was sharing the lead with Auriol. Behind them was Cunico, who last year drove a works Q8 Ford but is this year driving for Ford of Italy. Loss of brakes had delayed him a little, but the Italian was not too concerned. A remarkable achievement on that third day was that of Bugalski, who had got his underpowered and under-tractioned Renault Clio into sixth place. Alas, he dropped two places the next day, but it was nevertheless a fine performance which must have pleased Renault no end.
Renault is something of a dark horse team. Having once been at the spearhead of rallying, both with the Alpine which they took over from Dieppe and with their own Gordinis, they now seem poised for a come-back. No-one has said anything, nor even dropped a hint, and this remark is included merely as the result of a hunch. So much for that!
Chatriot began to show his mettle by getting ahead of Wilson, but later lost time when he had to stop after turbocharger failure (his second during the rally) to seal the oil feed pipe. Later, he lost some minutes having a hub replaced and was down in ninth place when the day ended. His engine had also been overheating and, due to a fail-safe device, had been producing much less than full power.
The final leg ran from Calvi via Baleone to Ajaccio, first passing very close to that town before looping away to the the three final stages in the South-East and returning for the finish in the afternoon.
Dark skies again turned breakfast conversations to tyre choice, but this time the unflappable Sainz was determined to shake off Auriol’s challenge. Bit by bit, second by second, he moved ahead, and on the last of the three long stages he jumped forward when Auriol’s Michelins began to lose their grip and his own Pirelli’s did not. That stage was the deciding factor, and Sainz emerged with a lead that Auriol could not possibly wear down.
All this talk of tyres “going off” has no bearing at all, of course, on the stock which we can all buy from the dealer down the road. Rally tyres are now as highly specialised as those used in F1 racing and, notwithstanding whatever advertising may be produced, the differences between one leading make and another are minimal.
Whilst Sainz had been charging the Toyota team with excitement, so Delecour had added to Ford’s misfortunes by succumbing to rear transmission failure. He stopped just two stages into the day and once again a brilliant performance came to a premature end.
Chatriot, after his turbocharger problems, seemed to squeeze extra zest from his Subaru on this last day, and even made a few best stage times, but forfeited all his gains when he lost a wheel on one stage and coughed his way to the end of another, his alternator malfunctioning and his battery flattened.
That was about the size of it. Sainz again showed his coolness, but not before Delecour, Schwarz, Auriol and others had demonstrated their ability. World Championship rallying is no longer a succession of one-horse races in which the prominent team manager has the freedom to decide which of his drivers should win. We are back at last to competition on equal terms. So far, Sainz is strongly defending his title. But the equally determined pretenders are very close on his heels. — GP
***
Results (top five) Tour of Corsica 1991:
Round 5 of 14 rounds, World Rally Championship for Drivers
Round 4 of 10 rounds, World Rally Championship for Makes
1. Carlos Sainz (E)/Luis Moya (E) — Toyota Celica GT4, Gp A — 7h 5m 29s
2. Didier Auriol (F)/Bernard Occelli (F) — Lancia Delta Integrale, Gp A — 7h 06m 34s
3. Gianfranco Cunico (I)/Stefani Evangelisti (I) — Ford Sierra Cosworth 4×4, Gp A — 7h 11m 39s
4. Marc Duez (B)/Klaus Wicha (B) — Toyota Celica GT4, Gp A — 7h 13m 12s
5. Malcolm Wilson (GB)/Nicky Grist (GB) — Ford Sierra Cosworth 4×4, Gp A — 7h 17m 19s
100 starters, 43 finishers
World Rally Championship Situation:
Drivers (top five) after 5 of 14 rounds: Carlos Sainz (E) 60 pts, Juha Kankkunen (SF) 38 pts, Didier Auriol (F) 32 pts, Massimo Biasson (I) 27 pts, Kenneth Ericsson (S) 20 pts. A total of 39 drivers have scored points
Makes (top five) after 4 of 10 rounds: Toyota 77 pts, Lancia 71 pts, Ford 28 pts, Subaru 20 pts, Nissan 10 pts.