• Just one petrol engine
• Two PHEV powertrains
• Top 550e model is rapid

Petrol engines

The 520i is the only petrol option you can buy. It’s a turbocharged 2.0-litre four-cylinder unit with 208hp and 330Nm of torque – and BMW claims it can propel the 5 Series from 0–62mph in 7.5 seconds before reaching a top speed of 143mph.

To maximise its efficiency, BMW teamed the engine with a 48-volt mild hybrid system and an eight-speed automatic gearbox. On paper, the formula seems to have worked because the engine returned fuel economy figures of between 44.1 and 49.5mpg in official WLTP tests.

Hybrid engines

There are two plug-in hybrid powertrains to choose from. The cheaper 530e model is based around a 2.0-litre four-cylinder petrol engine. It’s teamed with a 184hp electric motor and a 19.4kWh battery pack. Combined, the system has an output of 299hp and 450Nm of torque – and BMW’s claims it can return up 470.8mpg and cover up to 63 miles on electric power alone.

Above that, there’s the 550e. This is the only version of the combustion-engine 5 Series we’ve tried so far – and it flies in the face of convention. Instead of being based around a milk-bottle displacement three-cylinder petrol engine, it uses a twin-turbocharged 3.0-litre straight-six as its starting point.

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The engine is teamed with the same 19.2kWh battery pack, but it has a more powerful 197hp electric motor and, unlike the 530e, it features four-wheel drive. Combined, the powertrain churns out a whopping 483hp and 700Nm of torque, which is enough to whisk the 5 Series from 0–62mph in just 4.3 seconds.

What’s it like to drive?

• Razor-sharp steering
• Excellent handling
• Yet, it’s comfortable

The 550e is a seriously quick car. Its 0–62mph time is only a second behind the previous-generation M5 – and that vast reserve of torque makes the car incredibly flexible. And, because the 550e gets four-wheel drive as standard, you can use its performance in virtually any weather. We’ve tried the car in torrential rain, and never felt like we were overstepping the capabilities of the chassis.

Accessing all that performance is a bit tricky, though. Because the 550e is supposed to be a fuel-sipping motorway muncher, the throttle mapping is significantly dulled in any drive mode other than sport. Leave the car to its own devices and it’ll do its darndest to keep its petrol in its tank and potter around in EV mode.

There is a way around this, though. Much like BMW’s electric cars, if you pull and hold the left paddle on the steering wheel, you unlock ‘Boost’ mode. This winds the petrol engine and the electric motor up their maximum settings, unleashing the system’s entire 483hp for 10 seconds of madness.

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The acceleration isn’t severe enough to strain your neck, (thanks to the car’s substantial 2,230kg kerb weight), but it will pin you into your seat – and you get a satisfying and perfectly audible whoosh from the turbos each time the eight-speed gearbox snatches the next cog. It’s entertaining to drive quickly, which is important for a 5 Series.

What’s even more impressive is how nimble the car is. This is thanks in no small part to BMW’s rear-wheel steering system – an optional extra that our test car was, thankfully, fitted with. It has enough breadth of motion to make this five-metre-long frigate feel like a family hatchback.

At higher speeds, the rear wheels turn in the same direction as the fronts to improve stability – and it really does work. The car feels incredibly planted at motorway speeds. That stability is further improved thanks to the low-down weight of the PHEV’s battery pack.

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Don’t be fooled into thinking the 5 Series has become a one-trick motorway barge, though. The new car is equally good on a country lane. Like all BMWs, its damping has been set on the firmer side of comfortable – but that means it controls its body well in fast corners and it doesn’t wobble around over cross axle bumps.

If you crave a dash more rigidity for your favourite stretch of twisty road, you can switch the car into Sport mode. That firms up the damping, increases the steering weight and changes the throttle mapping – all of which helps to make the 5 Series PHEV feel a lot more focused and eager.

In some regards, the basic 520i is even better. It’s several hundred kilos lighter than the 550e and feels it in the corners. Even without four-wheel steer it feels happier under heavy braking and when changing direction quickly, but you do miss the pace of the brawnier plug-in hybrids. You have to work the engine hard to feel as quick as the numbers suggest, and it doesn’t make a particularly great noise whilst doing it.

BMW has done a good job with the 5 Series’ steering system, too. It’s not quite as communicative as the previous-generation models, but it’s very direct, very fast and offers just enough feedback to be fun. We’re not especially fond of the aggressively thick steering wheel rim, though. You need quite large hands to grip it properly.