Mansell left at the end of 1984 and his seat was taken by 1983 British Formula 3 Champion Ayrton Senna, who had impressed in his debut season with Toleman.
The first race of 1985 saw the debut of the Type 97T.
Senna surprised everyone with a lap in qualifying that would be good enough for his first pole position.
Senna�s run of good driving and good fortune gave him pole position for the following San Marino Grand Prix.
Round 5 in Canada saw De Angelis on pole for the first time that season, though he only managed to salvage 5th at the end of the race, with Senna a lowly 16th.
The French Grand Prix at Paul Ricard saw Senna on the front row of the grid yet again, but once more he retired.
The British and German races saw no points finishes for Team Lotus, though they were back at the next race in Austria with 2nd place for Senna and 5th for De Angelis.
The next race of the season was the Belgian Grand Prix, which had been abandoned in June.
There were no more points finishes for Team Lotus in the final 2 races of the season, though Senna claimed pole in Australia.
Lotus finished the season equal 3rd (with Williams) in the Constructors Championship, while Senna and De Angelis were 4th and 5th in the Drivers Championship.
At the end of the season, De Angelis announced that he was moving to Brabham for 1986, and Renault announced that they were pulling out of Formula One as a team, though would continue to supply engines to Lotus, Ligier and Tyrrell in 1986.
De Angelis stayed for his 6th consecutive season with Lotus, as did Renault for the 3rd with their Turbo engine.
Senna retired, but De Angelis hung on to claim 3rd in Rio.
The second round of the season was the Portuguese Grand Prix at Estoril.
Race day was cold and very wet, but Senna demonstrated his superb car control and speed in the dreadful conditions to win by over a minute from 2nd place Michele Alboreto.
Portugal also saw De Angelis claim 4th place out of only 9 finishers.
His luck also held for 57 out of 60 laps, until his engine blew and he had to settle for 7th place.
But it wasn�t all bad for Lotus as De Angelis won the race (after Prost had been disqualified).
Senna was also quickest in Monaco qualifying, but retired from the race.
De Angelis was again well placed to pick up the pieces with 3rd place in the principality.
The Detroit Grand Prix saw another pole and retirement for Senna after he had led for the first 7 laps, and also another 5th place for De Angelis, who was enjoying good reliability form his 97T.
This race marked the end of De Angelis�s 7 consecutive points finishes with his third 5th place in a row.
Round 11 at Zandvoort saw another double points finish for Lotus with Senna 3rd and De Angelis 5th, as did the Italian Grand Prix with Senna 3rd and De Angelis 6th.
Senna claimed a front row grid position and led nearly all of the race to take the victory, his second of the season.
The Grand Prix of Europe gave Senna his 6th pole position of 1985, along with 2nd in the race (from Nigel Mansell who dominated to take his first win) and yet another 5th place for De Angelis.
