Both vehicles gain Brake Energy Regeneration as standard across the range, a feature that improves fuel consumption in the 6 Series by up to 6.8 per cent.
The new 6 Series gets a more distinctive look with bigger 19-inch alloys and lower-profile tyres (245/40 front, 275/35 rear), a swooping contoured bonnet and dark chrome tailpipes.
The V8 Valvetronic powerplant remains the same, thumping out 270kW and 490Nm of torque and launching the 650i Sport Coupé from 0-100km/h in 5.2 seconds and the 650i Sport Convertible in 5.6 seconds.
Meanwhile, the Coupé’s fuel consumption is down 5.4 per cent to a combined 10.5 litres/100km, while the Convertible has dropped even further, down from 11.7 to 10.9 litres/100km.
BMW hopes the reductions will help flagging sales of the 6 Series of which just 57 were sold in the first 10 months of the year – 46 per cent below last year’s 105 at the same point.
BMW Australia managing director Stavros Yallouridis says the efficiency improvements plus the addition of features like the new generation iDrive system with an 8.8-inch high-definition TV screen and an 80GB hard drive and new sporting trim options are a real step up from the old model.
“The new BMW 650i Sport further shapes the top end of the BMW product portfolio and signals yet another example of BMW’s uncompromised BMW EfficientDynamics strategy.”
The new BMW 650i Sport Coupé costs $227,300 and the Convertible is $245,100 (both up $6000) before dealer and on-road charges.
Fuel and emissions savings also lead the changes in the Z4, with consumption improved by between 4.2 and 7.8 per cent across the range.
The automatic sDrive23i now uses 8.2 litres/100km and emits 192 g/km CO2 (down from 207), while the heaviest drinker and worst polluter is the manual sDrive35i at 9.4 litres/100km and 219 g/km.
Mr Yallouridis says the improvements come courtesy of the brake energy regeneration, optimum shift indicators on the dash and reduced rolling resistance tyres on the base model.
“BMW is committed to improving the efficiency of all of its cars, not just a few less powerful small cars.“There’s no reason why sports car drivers can’t meet their sporting and lifestyle needs whilst emitting fewer emissions and using less fuel.”
And drivers agree, with the Z4’s sales soaring almost 100 per cent year-to-date over 2008.
Other new features include electric power steering and a high precision injection twin turbo motor in the range-topping 35i.
The updated Z4 and 6 Series ranges will be on display in BMW showrooms later this month.
by Tim Beissmann