Despite its overwhelming success, the TAG-Porsche engines were never the most powerful in Formula One as they did not have the ability to hold higher turbo boost like the rival BMW, Renault, Ferrari and Honda engines. The McLaren drivers who regularly raced with the engine (Lauda, Prost, Keke Rosberg and Stefan Johansson) continually asked Porsche to develop a special qualifying engine like their rivals. However, both Porsche and TAG owner Mansour Ojjeh baulked at the requests due to the extra costs involved, reasoning that the proven race engines already had equal power and better fuel economy than all bar the Hondas, thus qualifying engines were never built. Though the lack of horsepower did not stop McLaren from claiming 7 pole positions (6 for Prost, 1 for Rosberg) and 21 front row starts.