Automotive Engineer

Premium SUVs are still liked by drivers, whether they are used offroad or spend their entire lives in an urban environment. Sitting higher than others on the road gives you a sense of security and perhaps a little superiority.

They’re profitable for OEMs too, but there are drawbacks: the distance you can travel on a litre of fuel and the amount of carbon emissions blowing out of the exhaust.

OEMs are unlikely to stop developing SUVs, however. BMW currently produces four – the X1, X3, X5 and X6 – all of which are popular.

But, as changes to emissions legislation take effect, consumer buying habits are changing, so OEMs have to bring the vehicles into line with other cars in their fleets and make them more fuel efficient.

In 2004 when BMW launched the first-generation X3 the most efficient powertrain was the 2-litre, four-cylinder diesel. It emitted 165g/km CO2 and used 5.2 litres of fuel to travel 100km.

The latest version boasts figures of 147g/km and 4.7 litres/100km, from its four-cylinder diesel. 

“That was the target,” says Lutz Römer, head of the X3 project. “Of course we could have lowered these emissions further but that would have meant reducing performance, and I think we have found a very good compromise between driving performance and emissions.”

The previous powertrain could only muster 104kW of power and 350Nm of torque. Römer and his team of engineers have increased this to 135kW of power at 4,000rpm and 380Nm between 1,750 and 2,750rpm. A 225kW six-cylinder gasoline engine is also available.

While improving efficiency is a challenge for every OEM, Römer also had to heed the criticism levelled at the previous vehicle: “We wanted on the one hand to keep the characteristics of the previous X3 but also to improve he areas that were sometimes criticised, especially ride comfort. So we have made a big step forward in terms of ride comfort but we also improved the agility and driving performance as well,” he says. Part of this was done by widening the X3’s track, increasing the length of the wheelbase and lowering the centre of gravity.

And, whether it’s an inline four or six under the hood, or refinement in the cabin, buyers want to have the ride and performance they associate with premium SUVs. That performance includes offroad ability. As some OEMs are moving away from all-wheel drive systems in smaller segment vehicles, BMW could have opted to remove the X3’s all-wheel drive system, and have an optional two-wheel drive version.

The X1 is available without allwheel drive and other OEMs are planning to do the same with their SUVs in an effort to improve efficiency, but this isn’t an idea Römer looks happy about.

“It was a possibility, but we didn’t spend long considering the option as the X3 first and foremost is an all-wheel drive