The Lotus 98T was a car designed by Gérard Ducaurouge and Martin Ogilvie. The 98T was a further development of the 97T from 1985. A total of four chassis were built of which three were for Ayrton Senna, while Johnny Dumfries got one chassis.
The differences from the 97T
The chassis of the 98T was lower than that of the 97T. This was due to a change in the rules concerning the capacity of the fuel tank.
Lotus planned to give Senna a car in 1986 that would be competitive for the championship. It gave the Brazilian a strong position in the team. Johnny Dumfries was chosen at the recommendation of Senna, at least, Ayrton did not want Derek Warwick to strengthen the team. We have reported extensively on this in our extra report entitled 'Veto'. Ayrton got the number one status in the team and it didn't really give Dumfries a chance in 1986. Dumfries had to accept a handicapped role, as he was instructed to help Ayrton.
Steve Hallam on the 98T
Senna's racing engineer Steve Hallam said: "The message we got was that the team should increase the intensity and support Ayrton, otherwise we wouldn't get the best out of him. Peter and Gérard realised that the Chapmans realised that and Renault realised that too. They quit their own factory team and have instead become our exclusive partner. We had very good support from them, but then Honda suddenly caught up."
The 98T qualified with special tyres, a different turbo, a different gearbox and an extreme version of the EF15B injection system. The amount of horsepower was increased to about 1200. With only 540 kilograms of weight, the car could only fly two laps at full power and full boost.
Hallam said: "We changed the turbos after each qualifying run, because it would get so stressed that they would be stressed after just one lap. The mechanics needed half an hour to change them, so the qualifying laps had to be at least half an hour apart. The turbos would turn red and the mechanics usually wore thick asbestos resistant gloves to loosen the nuts and bolts. The air around these mechanics was so hot that it was almost unbearable.
Renault makes a special engine
Renault developed a pneumatic valve system for the EF15B that made the engine lighter and smaller. It used compressed air to operate the valves mechanically instead of conventional valves. This provided reliability and speed. Despite its high cost and compliancy, it proved to have made great progress and was quickly taken on by other Formula 1 engine manufacturers. The same technology only reached MotoGP in 2002.
The EF15B also had a more advanced ignition system with coils in each of the six spark plug segments, which were managed by the car's ECU. The driver's fuel readout was updated every lap by radio signal. If the number of laps of fuel remaining on the display was greater than the number on the pit board, it was time to start racing. If it was less, the driver was saving fuel.
The smaller fuel tanks also had parts. Gérard Ducarouge was able to give the 98T a smaller, stronger carbon fibre and aluminium honeycomb frame. For its construction, he opted for an integral injection moulding approach such as Ferrari, Williams and McLaren. The cockpit height was reduced behind the driver and the space created by the smaller fuel tank was an ideal location to install the 'black box'.
Ayrton Senna Special: Part 1 - Ayrton and karting - The early years
Ayrton Senna Special: Part 2 - Ayrton and karting - International
Ayrton Senna Special: Part 3 - Ayrton and karting - The tough trip in Buenos Aires
Ayrton Senna Special: Part 4 - Ayrton and karting - The last race
Ayrton Senna Special: Part 5 - Ayrton in Europe - Formula Ford 1600 and the battle with Rick Morris
Ayrton Senna Special: Part 6 - Ayrton in Europe - A glorious year in Formula Ford 200
Ayrton Senna Special: Part 7 - Ayrton in British Formula 3 - Senna in a class of his own
Ayrton Senna Special: Part 8 - Ayrton in British Formula 3 - First signs of pressure and dirt game
Ayrton Senna Special: Part 9 - Ayrton in British Formula 3 - Shame at Oulton Park and another title
Ayrton Senna Special Exclusive Interview: Allen Berg: Ayrton drove against the British system
Ayrton Senna Special: Part 10 - Ayrton as a test driver - The first experience in a Formula 1 car
Ayrton Senna Special: Part 11 - Ayrton as a test driver - A selection of different teams
Ayrton Senna Special: Part 12 - Ayrton at Toleman - Why the choice for Toleman was the right one
Ayrton Senna Special: Part 13 - Ayrton at Toleman - Monaco Grand Prix - Stefan was faster
Ayrton Senna Special: Part 14 - Ayrton at Toleman - Monaco Grand Prix - Post-race
Ayrton Senna Special: Part 15 - Ayrton at Toleman - Competitive in a new car with two podiums
Ayrton Senna Special: Technical Analysis 1: The Toleman TG183 (1984)
Ayrton Senna Special: Teammate 1: Johnny Cecotto
Ayrton Senna Special: Part 16 - Ayrton at Lotus - Facial Paralysis
Ayrton Senna Special: Part 17 - Ayrton at Lotus - Masterclass in Estoril
Ayrton Senna Special: Part 18 - Ayrton at Lotus - An unfortunate first half of the season
Ayrton Senna Special: Part 19 - Ayrton at Lotus - Many podiums and a victory at Spa-Francorchamps
Ayrton Senna Special: Technical Analysis 2: The Lotus 972
Ayrton Senna Special: Teammate 2: Elio 'The Gentleman'
Ayrton Senna Special: Extra 1: Veto 1
Ayrton Senna Special: Part 20 - Second year at Lotus - Titanium competition with Nigel Mansell
Ayrton Senna Special: Part 21 - Second year at Lotus- A good start and the lead in the championship after Detroit (1986)
Ayrton Senna Special: Part 22 - Second year at Lotus - Decay in the second half of the season (1986)