The camouflage still hides much of the revised design but the new 3 will be a little wider and lower. Picture: BMW
The camouflage still hides much of the revised design but the new 3 will be a little wider and lower. Picture: BMW

BMW is doing final development work on the next-generation 3 Series ahead of its full reveal.

The latest testing has been in the area of a key BMW characteristic, driving dynamics and the company has been putting the new 3 through its paces at the Nürburgring Nordschleife.

Test runs at the legendary circuit, known as the "Green Hell", traditionally serve as a baptism of fire for the drive and suspension technology of newly developed models.

The company says an extensive testing programme was developed for the camouflaged prototypes of the new 3 Series which will benefit from substantial changes to wheel suspension, steering, damping, suspension and brakes.

The centre of gravity is said to be 10mm lower than in the outgoing model, axle load distribution is balanced at 50:50. BMW says the total weight adjusted for equipment is as much as 55kg lighter.

The rigidity levels of the body structure and suspension attachment — so crucial to the steering setup and ride acoustics — have been enhanced the company says.

Its agility and steering precision benefit from expanded track widths, while the wheel camber levels have increased.

In terms of the engine portfolio, one feature will be a thoroughly revised four-cylinder petrol engine, the most powerful four-cylinder engine to be fitted in a BMW series production model.

Yet its fuel consumption figures are claimed to be 5% below those of the predecessor engine, partly because developments have been made to the eight-speed Steptro-nic gearbox.

Damping system

Suspension upgrades aim to improve dynamics even more in the new generation. Picture: BMW
Suspension upgrades aim to improve dynamics even more in the new generation. Picture: BMW

Not only is the body lighter and more rigid in design than that of the outgoing model, the same is true of the front and rear axles.

A key feature in terms of suspension development is a new damping system. The first lift-related dampers to be fitted in a BMW model function continuously and progressively in relation to the respective spring travel. As such, the vibrations that occur when compensating for bumps on the road and during dynamic cornering can be neutralised gently and precisely, says BMW, and provide a balance between sporty flair and comfort.

"We’re using the lift-related dampers as an active setup element so as to create supreme driving properties in all conditions," says Peter Langen, head of driving dynamics at BMW. "With short spring travel, a sensitive damping response ensures comfortable vibration compensation. When the car passes over large bumps, the body movements are controlled by increased damping forces."

In a specific setup, the lift-related dampers form part of the M sports suspension, which includes lowering by a further 10mm, as well as 18-inch light alloy wheels and mixed tyres. The M sport suspension elements have increased damping forces by 20%, says BMW

"This means the difference from the standard suspension is more perceptible than before," says Langen. "We’ve also made the M sports suspension sportier, with more rigid bearings and stabilisers, harder springs and additional body struts."

To further reinforce the car’s dynamic nature, the new M sports suspension is offered solely in combination with the Variable Sports Steering. In addition to the speed-related steering assistance Servotronic, this also provides a variable steering ratio.

Variable Sports Steering has been specially reconfigured for the new generation 3, with BMW promising that it will respond with greater precision to slight steering movements, without seeming nervous in central position.

Changes to the setup of the steering will be felt on long bends, as well as when changing direction several times in rapid succession, says the company.

Then there is the M sports differential in the rear axle which is linked to Dynamic Stability Control, ensuring needs-oriented limitation of rotation speed compensation between the rear wheels on the inside and on the outside of a bend. Depending on the situation on the road, it is possible to pre-emptively influence both understeering and oversteering without brake intervention.

The active differential lock distributes drive torque selectively between the rear wheels preventing slip on a wheel with reduced surface grip, while ensuring engine power can be used unrestrictedly to generate sporty driving pleasure.

"Unlike conventional mechanical locks, the regulated M sports differential can optimise so much more than just traction," says Langen. "In addition to cornering dynamics, there is a tangible increase in drive stability in the event of load changes, for example. This allows the new 3 Series sedan to be driven remarkably confidently and effortlessly even when travelling in dynamic style."

For sporty driving, the active differential lock provides much higher levels of transverse acceleration, as well as a perceptible boost in dynamic performance when accelerating out of bends. It supports optimised stability, precision and cornering predictability without brake intervention.