BMW is virtually certain to cease its involvement in the World Touring Car Championship next year, when the series' new technical regulations are expected to come into force.
The German manufacturer last competed as a factory entrant in 2010, but has been represented by independent teams such as ROAL Motorsport, Wiechers-Sport and Team Engstler since then, while also selling its factory-produced TC engine on a customer basis. BMW's current 1.6-liter turbocharged engine is now in its third year of racing and has powered six victories. But the company's motorsports director Jens Marquardt says that BMW simply cannot improve its performance for 2014, in which engine power is set to be significantly increased as part of a series of performance-enhancing measures.
"I just can't see how we can get a powertrain together for the new regulations, which still aren't even set," Marquardt said. "They're talking about 400hp. That's impossible for us.
"We didn't do a Global Race Engine. Our TC engine was done on a 1.6-liter production block, and that's where our limitation is. We're already at the limit of performance on it and I've been told the FIA is targeting performance beyond what we can reach.
"Even the TC engine, which works with the current regulations, is not really the best of the projects we've done from a commercial point of view, so there's nothing really for us to look into."
Dominik Greiner, whose Wiechers team has run BMW machinery in the WTCC since 2005, admitted the introduction of new regulations could make staying with the marque impossible.
"From BMW's side, there is no way to get a new car for the 2014 regulations," he said. "I hope for the moment they postpone everything for a year, which would enable us to run this car next season.
"We would like to stay with BMW, because it's a fantastic brand, but I may have to keep my eyes open to a new brand. I hope as soon as possible to know the future: It's not fair that all the teams currently in the championship wait for decisions from new manufacturers."
BMW remains the second most successful marque in the WTCC since the series was revived in 2005, claiming 58 wins and taking three successive drivers' titles between 2005-'07 with Andy Priaulx. Only Chevrolet, with 74, has taken more victories.
SEAT is also represented in a non-factory capacity in the WTCC. It recently unveiled a new version of its Leon Supercopa, but insisted that it cannot even consider building an S2000-spec version of the car until it is given a definitive set of technical regulations for 2014 and beyond.