Paris show: BMW lets 3 Series cat out of the bag

BMW has surprised the motoring world by spilling a swathe of technical details of its new seventh-generation 3 Series sedan well ahead of its formal reveal at this year’s Paris motor show in October.

The factoids were detailed in a press release about testing of the new model at Germany’s Nurburgring where some European journalists were allowed to get behind the wheel of camouflaged 330i M Sport test mules.

Due to arrive in Australia about March or April next year, the new G20 model will get the most powerful four-cylinder engine ever fitted to a BMW, eclipsing the current 180kW/350Nm 2.0-litre turbo unit loaded into the front end of a number of current models, including the 330i.

Power and torque figures for the latest turbocharged 2.0-litre petrol engine – sufficiently new to be regarded internally as a new-generation powerplant – have not been formally disclosed, but Britain’s Autocar suggests power will rise about 6kw, to 186kW, while torque will be lifted an impressive 50Nm, to 400Nm.

These figures are nothing to write home about by comparison to the hand-grenade four-cylinder engines of some rivals, including Mercedes-AMG’s 280kW/475Nm A45, but BMW does not pretend this new engine to be anything but a mainstream unit, reserving its hi-po efforts to six-cylinder units packing more than 330kW.

BMW says the new engine will be mated with the latest iteration of the trusty ZF eight-speed automatic transmission, tweaks to which have helped to cut fuel consumption by a claimed five per cent.

The engine will be cleaner too, gaining a particulate filter to help the new model meet the latest European emissions standard.

BMW designers and engineers have dropped the centre of gravity by 10mm and gained a 50:50 weight distribution while also trimming about 55kg out of the overall weight “adjusted for fittings”, thanks to greater use of lightweight metals such as aluminium and magnesium in the latest rear-wheel-drive platform that already underpins new BMW models such as the 5 Series.

Some of the weight savings have been made in the front and rear axles that nonetheless are said to deliver “supreme yet sporty driver properties”.

New “lift-related dampers” will be standard across the range, arming the 3 Series with a suspension that neutralises vibrations from road impacts at the extremes of wheel travel.

Says BMW head of driving dynamics Peter Langen: “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.”

These dampers are also used on the M sports suspension that also includes a 10mm lower ride height, lightweight 18-inch alloy wheels and mixed tyres (wider at the back).

Tested at the famed Nurburgring, the M sports suspension showed damping forces 20 per cent higher than the standard set up.

“This means the difference from the standard suspension is much more perceptible than before,” Mr Langen said.

“We've also made the M sports suspension much sportier, with more rigid bearings and stabilisers, harder springs and additional body struts.”

The 3 Series’ steering has been tweaked to better respond to slight inputs while avoiding a nervous feel at the straight ahead.

Cars fitted with the M sports differential get an electronic lock linked to the ESC to allow for compensation between the rear wheels in corners.

“Unlike conventional mechanical locks, the regulated M sports differential can optimise so much more than just traction,” Mr Langen said.

“In addition to cornering dynamics, there is a particularly tangible increase in drive stability in the event of load changes, for example.

“This allows the new BMW 3 Series sedan to be driven remarkably confidently and effortlessly even when travelling in dynamic style.”

This system apparently provides “much higher levels of transverse action”, which is engineering speak for hanging the back out for some tyre-smoking action at full noise.

Mainstream variants of the previous-generation F30 3 Series – launched in 2011 – were made for Australia in South Africa, but as GoAuto has reported, all new 3 Series variants will come from Germany this time.