Having been very successful with turbocharged cars in the 1970s, Porsche returned to Formula One in 1983 after nearly two decades away, supplying water-cooled V6 turbo engines badged as TAG units for the McLaren Team. For aerodynamic reasons, the Porsche-typical flat engine was out of the question for being too wide. With turbo power being the way to go in F1 at the time a 90° V6 turbo engine was produced. The TAG engine was designed to very tight requirements issued by McLaren's chief designer John Barnard. He specified the physical layout of the engine to match the design of his proposed car. The engine was funded by TAG who retained the naming rights to it, although the engines bore "made by Porsche" identification. Initially, Porsche were reluctant to have their name on the engines, fearing bad publicity if they failed. However, within a few races of the 1984 season when it became evident that the engines were the ones to have, the "Made by Porsche" badges began to appear. TAG-Porsche-powered cars took two constructor championships in 1984 and 1985, and three driver crowns in 1984, 1985 and 1986. The engines powered McLaren to 25 victories between 1984 and 1987, with 19 for 1985 and 1986 World Champion Alain Prost, and 6 for 1984 Champion Niki Lauda.
https://en.wikipedia.org/wiki/Porsche_in_motorsport#Formula_One