His lap record on the Nordschleife configuration at the Nürburgring, set while qualifying for the 1000 km race in 1983, stood for 35 years, when it was beaten by Timo Bernhard in 2018.
Born in Gießen, West Germany, and following in his brother Georg's footsteps, Stefan Bellof made his karting début in 1973, competing in the Automobilclub von Deutschland's Federal Junior Cup, in which he ended up in fourth position.
Bellof moved into Formula Ford at the tail end of the 1979 season, as a member of Walter Lechner's Racing School setup, making his bow at Hockenheim in November 1979, where he finished in second place.
He continued in the series in 1981, but was not as successful as his championship-winning season, taking five wins and also made a foray into the more powerful 2000cc class, but retired from both his starts in the Lion Trophy at Zolder and the 300 km meeting at the Nürburgring.
At the conclusion of the season, Bellof contested the Formula Ford Festival at Brands Hatch, but was excluded from the meeting after finishing sixth in his quarter-final heat, for excessive contact.
"[5] Bellof joined Mike Thackwell and Alain Ferté at a test session with Maurer Motorsport at Circuit Paul Ricard in France at the end of the 1981 season.
He followed this win up with a second successive triumph at the Jim Clark Gedächtnisrennen at Hockenheim, having started from pole position and achieved the fastest lap during the race.
While competing in Formula Two in 1982, Bellof made a one-off appearance in the World Endurance Championship at the 1000 km of Spa, partnering Rolf Stommelen at the wheel of a Kremer CK5.
[11] The previous weekend, Bellof had joined Kremer to compete in the Hessen Cup at Hockenheim as part of the Deutsche Rennsport Meisterschaft, but retired with transmission failure.
After crossing the line first, their 956 was promptly disqualified in scrutineering with the car found to be under the 850 kg (1,874 lb) weight limit, which would also apply to the third-placed Martini Racing Lancia LC2.
[21] Bellof did move into the championship ahead of the 1984 season, joining Tyrrell Racing Organisation, to partner Brundle in naturally aspirated, Ford-engined machinery, which were giving away in excess of 150 horsepower (110 kW) to their turbo rivals.
Despite starting down in 20th and last place, Bellof remained away from the barriers that caught out many of his rivals, and was catching the race-leading pairing of Alain Prost and Senna[22] when the race was curtailed after 31 laps due to inclement weather conditions.
[23] Retirements followed in Canada and in Detroit, where Brundle claimed the team's best result of the season with second position as Bellof stuck his Tyrrell in the pit wall.
[5] However, Bellof, Brundle and the team were stripped of all their championship points, after their cars were disqualified from the 1984 season after a dispute over lead ballast in their fuel tanks found after the Detroit Grand Prix.
Tyrrell had only changed to such engines from the German Grand Prix onwards meaning that Bellof never truly had the opportunity to show his talent at the wheel of a Formula One car.
On lap 78, Bellof was racing Jacky Ickx's works Porsche 962C from the La Source hairpin on the run to Eau Rouge corner.
The Brun Porsche caught fire moments after the wreck, while Ickx – able to climb unaided from his car – attempted to help safety workers in extricating Bellof.
At the previous World Sportscar race at Mosport Park in Canada, fellow West German and F1 driver Manfred Winkelhock died of severe head trauma after crashing into a concrete wall while at the wheel of a Kremer Racing-run Porsche 962C.
[citation needed] In 2010 Bellof's family donated his racing mementos to the local Sammler und Hobbywelt museum for public display.