BMW's i8 Roadster is a 1.5-litre petrol-electric hybrid with sports car credentials
Topless wonder: BMW's i8 Roadster The BMW i8 Roadster can go up to 105kmh on pure electric energy. PHOTOS: BMW

The BMW i8 has been the world's best-selling hybrid sports car since its debut in 2014.

It is easy to see why. It looks like a million-dollar supercar, but costs about half as much. Maintenance, road tax and fuel bills for this 1.5-litre, electrically boosted car are also a fraction of those for a V8 sports model.

Like its coupe brethren, the new convertible i8 is an amazing piece of engineering. An electric motor drives the front wheels via a two-speed gearbox and BMW's familiar three-cylinder turbocharged engine powers the rear wheels.

The 1.5-litre engine makes 231hp and 320Nm - the highest output of any BMW 1.5-litre. The electric motor's peak output is 12hp more than the i8 coupe's at 143hp, courtesy of increased battery cell capacity.

The lithium-ion battery is located under the centre of the car. With a light right foot to prevent the engine from kicking in, the car has an electrical range of 53km.

The roadster can go up to 105kmh on pure electric energy. It extends to 120kmh if the eDrive button on the centre console is engaged in conjunction with Comfort or Eco Pro mode. I was, however, unable to verify this.

In unison, both power plants offer all-wheel-drive, with a total output of 374hp and 570Nm, propelling the 1,595kg carbon-aluminium roadster (the coupe is 60kg lighter) to 100kmh in 4.6 seconds.

Although this is not supercar fast, it is enough on the autobahn to scare lesser cars into giving way. The i8 Roadster closes up any gap in traffic quickly. Its top speed is electronically limited to 250kmh, and I breached 240kmh - with a lot more oomph in reserve.

This car is more than a technological marvel. It turns heads every time. A driver in a BMW M4 looked at us with envy. Motorists gave way in traffic jams to gawk at it.

It is a doddle to drive in heavy traffic as visibility is good all-around, even with the top up.

Gull-wing doors add to the occasion. It takes a certain technique to enter the car gracefully, though. The way is to sit on the seat across the sill and then rotate your torso and legs into the footwell. Egress is the reverse.

Once inside, you are in a special world of straights and curves that blend seamlessly. Build quality is of BMW's high standards. Its soft-top is well-insulated and takes only 15 seconds to open or close.

The rear seats of the coupe have made way for the soft-top mechanism. But the convertible still has around 100 litres of storage space behind the front seats - enough for a shopping spree.

The gym bag and toothbrush can be consigned to the rear boot, which is smaller at 88 litres.

The i8 Roadster does not quite handle like an all-out sports car, though. The Audi R8 Spyder does, with sharp steering and virtually no body roll when executing a fast corner. The BMW, however, has a more pliant ride, which will soak up Singapore's bumpy roads better.

Floor the throttle and you will never guess that the howl of the engine comes from a humble 1.5-litre three-cylinder. This, of course, is aided by an electronic sound amplifier.

In Sport mode, both power plants work at their maximum intensity while charging the battery in full tilt on the overrun and under braking.

There are some cars which you are reluctant to return after a test-drive. The BMW i8 Roadster is one of them. It may not be the fastest or best-handling car for the money, but it tugs at the heartstrings nonetheless. Especially after a drive through scenic winding roads, fast autobahns and slow city traffic.