Porsche's return to Formula One as an engine supplier in 1983 came at the direct invitation of McLaren chief designer John Barnard, who specified the physical layout of the engine to integrate with his proposed monocoque design. Because Porsche's traditional flat-opposed engine layout was too wide for aerodynamic packaging, engineers departed from their usual architecture and produced a 90-degree V6 turbo. Mansour Ojjeh's TAG group agreed to finance the entire development program, with the condition that the engines would carry the TAG name. Porsche was initially reluctant to associate their marque with the project in case the engines failed, but once results vindicated the design, "Made by Porsche" identification began appearing prominently.
The TAG-Porsche was designed around tightly specified physical envelope requirements set by Barnard. The 90-degree V6 configuration with twin KKK turbochargers allowed it to be integrated as a stressed structural member within the McLaren chassis. Displacement was 1,499 cc, within the 1.5-litre turbocharged limit that governed Formula One from 1977 to 1988.
Throughout its competitive life the engine was noted for reliability and fuel economy rather than outright peak power. Unlike some rival units from BMW, Renault, Ferrari, and Honda, the TAG-Porsche was never developed into a dedicated qualifying engine capable of running maximum boost for a single flying lap. McLaren drivers including Niki Lauda, Alain Prost, Keke Rosberg, and Stefan Johansson repeatedly requested a qualifying-specification engine, but Porsche and TAG owner Ojjeh declined on cost grounds, reasoning that the race engine already matched rivals on power while bettering them on fuel consumption — an important factor under the mandatory fuel-load limits of the era.
The TAG-Porsche-powered McLaren MP4/2 made its debut in mid-1983, and the package became fully competitive from the 1984 season onward. Between 1984 and 1987, TAG-Porsche-powered McLarens claimed 25 victories and three consecutive drivers' world championships: Niki Lauda in 1984, and Alain Prost in 1985 and 1986. Prost accumulated 19 of those victories. McLaren also secured the constructors' championship in 1984 and 1985.
The 1984 season was particularly dominant, with McLaren winning twelve of the sixteen rounds. Despite lacking the raw qualifying pace of the turbocharged Honda that eventually displaced it, the TAG-Porsche engine proved that refined reliability and drivability could compensate for a peak-power deficit over a full season.
By 1987 the Honda engine had surpassed the TAG-Porsche in outright performance and McLaren moved to Honda power for 1988. The TAG-Porsche thus powered McLaren's last season of competitive turbocharged racing in 1987 before the new normally aspirated formula supplanted the turbos entirely for 1989.
Porsche attempted another Formula One engine program in 1991, supplying the Footwork Arrows team with a naturally aspirated V12 designated the 3512. That program was widely described as catastrophic — the engine was overweight, underpowered, and unreliable, failing to score a single point and failing to qualify for more than half the season's races. It bore no meaningful technical relationship to the successful TAG-Porsche turbo unit. After the Footwork affair, Porsche did not participate in Formula One again.
The TAG-Porsche remains one of the most celebrated engine programs in Formula One history, defined less by peak specification figures and more by its engineering balance and the championship results it underpinned. Its three drivers' titles and 25 race victories between 1984 and 1987 represent the high-water mark of Porsche's involvement in Formula One single-seater competition.