Electronic Power Steering (EPS)
The safe bet is that it’s coming and will be standard on the full range of F30 vehicles. It doesn’t make any sense for BMW to develop it, deploy it on both the 7 and 5 series and not utilize it on the 3er. There are fuel consumption benefits to be had and BMW takes their devotion to EfficientDynamics seriously.
The rap on electric power steering is that it doesn’t provide sufficient steering feel. And when even Consumer Reports complains about reduced steering feel in the new 5 series you have to take notice. I have not been a fan of any electrically assisted steering, but this generation of BMW’s EPS is the best of the bunch I’ve sampled. It still isn’t as good as the best hydraulic steering racks or manual steering racks (but then how well can you steer a 1500kg car with a manual rack).
It’s interesting to hear the take on the usefulness of steering feel from various race drivers. Some insist that they get every scrap of info possible from the tires passed up into their hands, other’s are just looking for consistency and the little vibrations and other info that can be passed up from the tires is not all that vital to the task.
If steering feel is really of primary importance then most BMW’s will fall a bit short, try a Porsche or an NB Miata instead. And whatever you do, don’t expect world class steering feel from runflat tires. Tires are responsible for a lot of what’s perceived as steering feel and runflats aren’t known for their brilliant tactile sensations.
All that being said, if you want a hydraulically assisted power steering rack on your next 3er, maybe you should be planning on buying an E90. It will interesting to see if the next gen M3 uses EPS though.
Eight Speed Automatic
The ZF 8HP transmission is another piece of EfficientDynamics. It’s about six percent more efficient than the 6 speed auto it replaces but it has some additional tricks above and beyond enhanced fuel economy.
The core of the transmission is four epicyclic gear sets and five shifting elements. That gives it eight forward speeds and reverse. In a conversation with a BMW engineer, I facetiously asked how many reverse gear ratios they could do, he chuckled and said a few but didn’t think they would ever introduce a car with more than one.
The truly trick piece of this tranny is that it can accept a variety of interfaces between the engine and tranny core. There’s the usual torque converter, that’s ubiquitous in automatic transmissions (the torque converter obviates the need for a clutch between the engine and tranny). It can also be equipped with an electric motor. Soon more BMWs will
utilize the electric motor nose that will hybridize the car. We’ve published rumors of a diesel four cylinder X5 utilizing the electric motor nose of the 8HP. Expect a four cylinder F30 with that nose in the near future. Then there is also a dual-clutch module that could possibly replace the existing DCT.
An additional feature, from a fuel economy standpoint, is that the ZF 8HP is the first automatic that is compatible with stop/start. We sampled stop/start in the press preview of the X3 and came to the conclusion that it will feel totally seamless when coupled to the hybrid (electric motor) module.
This is a little known piece of gear that allows a great deal more integration of the various vehicle electronic modules. It is migrating down from the 7 and 5ers into the F30. It will find its way into pretty much the entire model range before long. The cost of development requires that it be spread across as many units as possible.
FlexRay acts as a ‘bus of buses’, it basically is a high bandwidth bus that interfaces to the lower bandwidth CAN buses utilized by the majority of the vehicles electronic modules. It doesn’t just act as an interconnect though. It also routes priority messages between buses. One way of grasping what FlexRay allows is to think about the communication
required between the cruise control code, ECU, and the ABS system in an active cruise control, stop and go, system.
The proliferation of government regulation requiring reduced fuel consumption and carbon dioxide emissions is driving manufacturers nuts. When Aston Martin has to re-badge a Toyota iQ to help with their emissions numbers you know things are warped beyond belief. BMW’s approach has been to find a lot of little things that add up to fuel consumption and emissions savings. EPS and the ZF 8HP automatic transmissions are just two additional pieces in their EfficientDynamics portfolio.
The difficult task that BMW faces is how to steer a course towards efficiency while retaining the driving dynamics drivers expect from a BMW. And it’s getting even more difficult. BMW has to make sure they maintain a focus on the driver’s seat in the F30. If the new 3er misses the mark with potential buyers . . .