Larrauri first appeared in the World Sportscar Championship in 1983, sharing a Lancia LC1 for Scuderia Sivama Motor. From 1984 he joined Brun Motorsport, the Swiss privateer operation run by Walter Brun, becoming one of the team's most consistent drivers across the Porsche 956 and then the Porsche 962C era. Alongside WSC racing he also competed for Brun in the Deutsche Rennsport Meisterschaft, the IMSA GT Championship, and the All Japan Sports Prototype Championship.
His strongest WSC seasons were 1986 and 1987. In 1986 he finished sixth in the championship with Brun, a season that included second overall at Le Mans — sharing the Porsche 962C with Joël Gouhier and Jesús Pareja — and a race win at the 360 km of Jerez. In 1987 he finished seventh in the championship, adding podiums at the 1000 km of Monza, the 1000 km of Nürburgring, and the 1000 km of Spa. He also finished second at the 200 Miles of Norisring that year.
Walter Brun's decision to enter Formula One for 1988 led to the creation of EuroBrun Racing, a partnership between Brun Motorsport and Giampaolo Pavanello's Euroracing team — which had previously operated the factory-backed Alfa Romeo F1 programme from 1982 to 1985. Larrauri was signed alongside 1987 Formula 3000 champion Stefano Modena.
The EuroBrun ER188, powered by a Ford Cosworth DFZ V8 producing 590 bhp, was one of the slowest cars of the season. Larrauri qualified for only eight of the sixteen rounds. His best finishes were 13th in Mexico and 16th in Germany. His tendency to impede lapping cars drew comparisons to René Arnoux's reputation for similar behaviour. Brun sought to replace him mid-season but found no available substitute who could fit the car, and Larrauri continued through to the final round in Australia.
Larrauri did not secure a drive at the start of 1989. He returned with EuroBrun for the last five Grands Prix of the season — the team now fielding the ER189 with a Judd CV V8 — but failed to pre-qualify at each attempt, ending his Formula One career without a championship point from 21 entered events.
Back in the World Sportscar Championship from 1989 with Repsol-backed Brun Motorsport, Larrauri remained competitive. He finished third at the 1989 480 km of Jarama and second at the 480 km of Mexico, ending the season seventh in the championship. He continued racing with Brun through 1990 and 1991, finishing tenth overall at the 1991 24 Hours of Le Mans. A one-off Le Mans appearance followed in 1994, sharing a Ferrari 348 GTC-LM for Ferrari Club Italia with Joël Gouhier and Fabio Mancini.
In later years Larrauri remained active in Argentine domestic racing, compiling an extensive record in series including the Fiat Linea Cup Argentina.
Larrauri's career captures the dual reality of 1980s international motorsport: a driver who was consistently effective at the highest level of endurance racing — anchored by his Le Mans podium in 1986 — but who could not convert that form into results within a severely underfunded Formula One entry.