|Chassis||Carbon fibre and Kevlar Aluminium honeycomb monocoque|
|Suspension (front)||Double wishbones, pull-rod actuated coil springs over dampers, anti-roll bar|
|Suspension (rear)||Double wishbones, pull-rod actuated coil springs over dampers, anti-roll bar|
Front: 1,816 mm (71.5 in)|
Rear: 1,620 mm (64 in)
|Wheelbase||2,720 mm (107 in)|
|Engine||Renault Gordini EF15B, 1,492 cc (91.0 cu in), 90° V6, turbo, mid-engine, longitudinally mounted|
|Transmission||Lotus / Hewland 6-speed manual|
|Weight||540 kg (1,190 lb)|
|Notable entrants||John Player Team Lotus|
11. Johnny Dumfries|
12. Ayrton Senna
|Debut||1986 Brazilian Grand Prix|
The Lotus 98T was a Formula One racecar designed by Gérard Ducarouge & Martin Ogilvie, and built by Team Lotus. It was made to compete during the 1986 Formula One season, and was a development of the Lotus 97T of 1985. Of the four chassis built, three were assigned to lead driver Ayrton Senna, now in his second year with Team Lotus, and one to team mate Johnny Dumfries.
The chassis featured a lower monocoque than the 97T as a result of a regulation change stipulating a reduction in fuel capacity to 195 litres. The powertrain consisted of the new Renault EF15B turbocharged V6 engine, driving through a six-speed, manual sequential Hewland gearbox.
The EF15B was to appear in two forms, the standard engine and the "D.P." engine which featured pneumatic valve springs for the first time. At the end of the season Renault introduced the revised EF15C which in addition to the D.P. valve gear also boasted common rail fuel injection and much revised water cooling through the cylinder head reducing the likelihood of pre-ignition (detonation). Power figures for this period of F1 history are largely speculative as most engine manufactures freely admitted that their test beds would not have a sufficient power rating to measure the 1.5 litre turbos output at above 4 bar boost. It is claimed that the Renault EF15B in its pinnacle increment was claimed to produce in excess of 1000 HP at unrestricted boost pressure, thus making it one of the most powerful engines ever used in Formula 1 history. 
This was however during qualifying, where teams used unrestricted boost pressures for maximum power output, and for very quick lap times. These unrestricted engines were very unreliable, and would only last about a couple clean laps. Therefore, the 98T produced around 900 HP in race trim. The 98T was also the final Lotus powered by a Renault engine, as Lotus switched to Honda for the following year/season.
The gearbox came in two variants, a conventional five speed and a new six speed. The six speed was very much a development gearbox and was largely unreliable. While Senna opted to run only with the five speed, Dumfries was tasked with testing the six speed. Both gearboxes featured Hewland internals within a Lotus designed casing.
Other notable innovations of the 98T included a two-stage ride height adjustment, water injection through the intercoolers, an early form of barge board (also present on the 97T) and an advanced (for the time) fuel consumption micro computer.
During the 1986 Formula One season, the Formula One paddock was very much alive with speculation as to the legality of the Lotus 98T. The increasing rumours prompted Lotus team manager Peter Warr to issue a press statement after qualifying for the German Grand Prix, calling for the rumours to stop or for the teams to officially protest the car. While the rumours died down, they did persist, although no protest was ever lodged.
At the end of 1985, long time Lotus driver Elio de Angelis had departed for the Brabham team. This left a seat open at Lotus and the team intended to sign Derek Warwick, without a drive after the factory Renault team pulled out of racing, as his replacement. However, Ayrton Senna, not believing that the team could sustain two #1 drivers and not wanting the focus of the team to be on anything but himself, used his position as the team's lead driver to put pressure on Lotus not to sign Warwick, allegedly even threatening to follow de Angelis to Brabham if they did sign the Englishman (though that couldn't happen as Riccardo Patrese, a favourite of Brabham boss Bernie Ecclestone, was already confirmed as de Angelis' new team mate). Lotus management however took Senna's threat seriously and decided not to sign Warwick. Senna then pushed to have his former flatmate and countryman Maurício Gugelmin join the team as the #2, but this time didn't get his own way. Team sponsor JPS reportedly wanted a British driver, so Lotus hired Dumfries instead.
Gugelmin would not make his F1 debut until he joined the March team in 1988, while Warwick, who was forced into sportscar racing in 1986 after being left without a drive, would ultimately replace de Angelis at Brabham after the Italian's death in a testing accident at the Paul Ricard Circuit in May.
The 98T was the last Lotus to carry the famous Black & Gold colours of long-time team sponsor John Player Special (JPS). As Renault were pulling out of F1 after the 1986 season, Lotus signed a deal with Japanese giant Honda to supply their engines in both 1987 and 1988. Part of the Honda deal was the team agreeing to sign their official test driver Satoru Nakajima as Senna's team mate. JPS, who wanted a British driver in the team, pulled its sponsorship and in 1987 Lotus would carry the Gold & Blue colours of another cigarette brand, Camel.
Complete Formula One results
(key) (results in bold indicate pole position)
|1986||John Player Team Lotus||Renault Gordini EF15B
- "Lotus 98T". statsf1.com. Retrieved 30 January 2017.
- "The power and the glory. Lotus 98T". thelotusforums.com. Retrieved 4 February 2017.
- "Video: Onboard the Terrifying Lotus 98T Turbo F1!". turnology.com. 25 March 2016. Retrieved 10 August 2017.
Lotus production car timeline, 1950–present
|Sports racer||Mark VIII||Mark IX||Eleven||15||17||19||23||30||40||47||62|
|Grand tourer||Elan +2||Elite|
|Saloon||Ford Cortina Lotus||Ford Cortina Lotus||Carlton/Omega|