At the international media launch of the new BMW X4 and 4 Series Gran Coupe, AutoExpress UK and BMWBLOG chatted with Klaus Frolich, head of small and midsize cars at BMW. Among many topics, the latest ZF-built 9-speed gearboxes came to front.
Currently using eight-speed automatics, seven-speed dual-clutches and six-speed manuals, BMW covers a wide range of vehicles, from 3-cylinder units to four, six and eight cylinder powered cars. BMW is convinced its current transmission policy is the perfect combination between efficiency and performance.
Frolich also expressed skepticism at the gearbox policies of rivals Jaguar Land Rover, Mercedes and Cadillac, all of whom are working on transmissions offering nine or more forward speeds.
“We ran some tests” explained Frolich. “The [efficiency] difference between an automatic with six speeds and eight speeds is seven or eight per cent, which is a good result. But the benefit for nine speeds [instead of eight] is almost zero per cent. Plus, it adds weight, complexity and cost, and with turbocharged engines you have a good spread of torque, so [drivers] do not want to have the gearbox constantly changing its mind.”
At the same time, Frolich says that the 7-speed M-DCT are not optimum, but rather a compromise.
“Seven gears is not optimum, it is a compromise. As in a manual gearbox, in a twin-clutch you must arrange all the gears in a line, so for weight and packaging reasons we are limited to seven speeds. But our new turbo M cars have so much torque this is no problem. DCT remains right for M cars because we can’t make a torque-convertor that would be durable up to 8000rpm.”
For the enthusiasts, Frolich also confirmed that for the foreseeable future, the manual transmission is safe at BMW, both in M Division cars and regular non-performance models. “Of course, with a manual you are slower, but it is more emotional; it now says ‘I am a serious driver, I am a connoisseur’. So, we will continue [to offer a manual] even if only ten per cent of customers want it. That is why we offer a manual M5 sedan in North America. It is stupid – the development costs are huge – but we will keep doing it as long as the customer wants it.”