BMW sticks to its guns for future gearboxes

27 May, 2014 10:33am Oliver Kew

Future BMWs won’t chase efficiency with nine or more gears, but will get three-cylinder power, according to tech chief

BMW is convinced its current transmission policy of eight-speed automatics, seven-speed dual-clutches and six-speed manuals is the perfect combination, according to its small and midsize cars boss, Klaus Frolich.

Speaking to Auto Express at the launch of the new X4 and 4 Series Gran Coupe – both of which offer an eight-speed ‘Sport Auto’ paddleshifter option – Frolich expressed scepticism 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.”

Quizzed over the policy to equip BMW’s M Division cars with a seven-speed dual-clutch gearbox (known as M-DCT), Frolich said: “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.”

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.”

BMW unconvinced by Audi prediction 

Asked about the possibility of three-cylinder engines in larger cars like the 3 Series and 5 Series, Frolich was unconvinced by Audi CEO Rupert Stadler’s prediction that this will become the norm within ten years. That’s despite four-cylinder turbo engines having beginning to usurp thirsty six-cylinders in the large executive saloon and estate class, in Europe at least.

Frolich forecasted: “[small engines in the larger cars] will happen, but only when the buyers are ready. Many buyers don’t care how many cylinders are in their BMW, and the new MINI shows the potential for three-cylinder. But honestly, it is much easier for us to make three-cylinder engines work with front-wheel drive than rear-wheel drive.”

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Honest interview. Having driven the 8 speed BMW gearbox, whilst very impressive and smooth, at times it felt like it was constantly changing gear, particularly through a long period of moderate acceleration, say when you join a fast A road from a junction. So I share Frolich's scepticism at having any more cogs in a gearbox.

Of course eight is enough, especially considering that the upper four speeds have overdrive gearing and that the typical eight-speed "sports sedan" can't pull itself to the redline in those four upper gears.

All this in the name of fuel economy. In fact, those tall-geared transmissions, as well as the newer CVT transmissions, are mostly adept at lugging the engine during government-mandated fuel economy test runs.

In real world driving, though, things are different. If you want to achieve the promised fuel economy, you will also have to play the lugging game. But if you want performance from your sports sedan, prepare to shift the auto transmission manually or be constantly agressive with the pedal kickdown.

I still prefer a six-speed manual, but lo-and-behold, these too have been tall-gearinged. One can lose his driver's permit in thid gear.

Yes I know what you mean,and when you add that there's the lock up clutch on most gears it makes a very busy gearbox.My 4 sp auto has lock up on 2,3 and 4th gears,does that mean there's 7 ratios ? Sort of as the revs drop on lock up.So a complex multi-geared gearbox for a city and suburban driver isn't necessary.I like well proven old tech over slightly more economy and possible problems.

Of course they do. They've been making the exact same car for 20 years.

Buyers don't care about the numbers of cylinders etc. Sounds true enough. They seem to care about image hugely and not a lot else. They can dress it up however they like by saying 'residuals' and so on. A fancy German badge with poor equipment, conservative styling, a disproportionate price tag and a rock hard ride is deriguer... Init. Premium product BS.

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