BMW 518d saloon first drive

BMW's 5-series with a new generation of four-cylinder diesel engine, offering reduced emissions and reputedly improved consumption.

Pleasingly, the new 'B47' 2.0-litre diesel, which replaces the 'N47', is also more powerful – albeit marginally – than the engine it supersedes. BMW has thusly acquired some cake, and consumed it.

The all-new 'TwinPower' turbocharged diesel, which features a single variable-geometry turbocharger – despite what its name suggests – utilises BMW's latest 'modular' design, entailing a 500cc displacement per cylinder.

Other changes compared to the previous 518d version of the N47 include a higher-pressure common rail injection system, which now operates at 2000 bar as opposed to 1600 bar, and new injectors. These upgrades grant more precise fuel metering and better atomisation, resulting in a more efficient combustion cycle.

There are also myriad other tweaks. At low engine speeds and loads the pump's flow can be throttled back, for example, cutting the power required to drive it and improving overall efficiency.

The net result of all these upgrades is a hike of 7bhp, taking total output to 148bhp. The claimed average economy rises from 62mpg to 64.2mpg, while CO2 emissions drop from 119g/km to 115g/km. Torque remains unchanged however, at 266lb ft.

Fractional gains at best, admittedly, but as VED, company car tax and fuel costs become ever more prominent concerns, and consumers are oft considering downsizing into a smaller car, every little helps in order to maintain the competitiveness of the larger saloons.

Some may be somewhat disappointed to see the new engine retain the rear-mounted and often-problematic timing chain assembly of its predecessor, however; alas the company has had to retain it in order to grant the required bonnet clearance to meet pedestrian crash regulations – which was also the original reason for that design choice. Hopefully, by now, any potential issues have long been engineered out.

We tested a 518d in 'Luxury' specification, a mid-grade trim, with the optional paddle-shifted eight-speed torque convertor automatic and variable damper control – all of which would set you back £35,735.

This, it appears, is a particularly fine combination to opt for. Firstly, you get the slick-shifting, easy-going ZF eight-speed automatic, the wide ranging ratios of which make good use of the diesel's output.

Secondly, besides vast amounts of kit, this trim level equips the 5-series with 18-inch alloy wheels and tyres with a substantial amount of sidewall. Consequently the 5-series rides in a pliant, cosseting fashion that befits its executive saloon nature.

Lastly, and wrapping up the package neatly, the addition of the variable damper control gives the 5-series a wider-ranging breadth of talent than the standard 5-series. A new Comfort+ mode delivers a smoother ride than was possible previously, or, if desired, a Sport mode offers improved responses, minimised body roll and better comfort in high-speed cornering situations.

Is the 518d's engine capable of summing up the kind of performance and refinement that a luxury saloon necessitates though? Well, almost. The 0-62mph sprint is dispatched in a sensible 9.4sec, and in-gear acceleration proves swift enough to not be an annoyance. Above 1500rpm the diesel pulls with comparative vigour, up until around 3500rpm, after which its performance tails off.