BMW i8 Roadster 2018 Review

Tech-laden glamour puss

Given the cutting-edge plug-in hybrid technology and carbon construction that makes up the BMW i8, it was quite revealing that there was no technical presentation at the international launch of the new i8 Roadster.

This, unashamedly, is the glamour puss of the range, which may at first sound ludicrous given the i8 Coupe’s ability to stop traffic and draw smartphone-wielding crowds wherever it parks up.

And yet, the first time you clap eyes on the Roadster, it makes sense, as it’s even more spectacular looking, even more attention grabbing, while staying true to the original concept.

At a glance, it appears that the Roadster might be more of an i8 ‘Targa’ with a roof panel that can be removed, but everything above the waistline is different – and more besides.

The windscreen frame is all-carbon and reinforced, and the doors, while still of the dramatic gullwing persuasion, are new too, as they don’t have frames around the glass, as the Coupe does.

The roof itself is a fabric section that folds away out of sight in a vertical position underneath the heavily buttressed rear, which lifts up to accommodate it before easing back down into position.

That action takes 15 seconds and can be done at speeds of up to 50km/h if need be. Or you could stand outside the car, looking cool, holding down the button on the key fob while everyone watches the roof’s balletic performance…

The extra side windows of the Coupe are gone (replaced by stylish looking panels bearing the ‘Roadster’ script) and the slope of the Roadster’s bodywork is lower than the Coupe’s.

Behind the cabin there’s a new window that can be raised or lowered independently of the roof. It acts as an effective wind deflector at speed, though it’s not needed below 120km/h unless you’re particularly tall (or your hairdo is).

Indeed, with it and the two door windows retracted, and the roof still in place, you get most of the Roadster sensation, without the sun beating down on your head.

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Inside story

That’ll give you a chance to look around the upgraded i8 cabin, which applies to both Coupe and Roadster (though the latter does without what BMW calls rear ‘seats’ in the Coupe).

It’s not very different to before, unless you go for the bright orange new upholstery option, though the infotainment has been updated so the screen mounted in the middle uses BMW’s latest ‘tile’ layout and operating system.

Apparently, it’s also touch-sensitive, but, as its position in the car hasn’t changed, it’s not realistically within reach of the driver, so it’s just as well that the traditional rotary iDrive controller is present and correct and as easy to use as ever.

The buttons for the drive modes are unchanged, but worth a revisit, as they work a little differently to those in other current BMWs.

The car defaults to hybrid Comfort mode, using combinations of electric and petrol power as it sees fit. You can eke out every litre of unleaded and every volt by toggling into Eco Pro mode.

Response isn’t great in this guise, but the i8 proves to be surprisingly efficient on a long journey. The driver can also press the eDrive button to maximise driving in purely electric mode – and then choose between Comfort and Eco Pro settings once more.

With the roof down, the i8’s silence in this guise seems enhanced, especially in a confined area, where the distant whirring of the electric motor up front and crunching of the tyres through the grit is all that you can hear. It emphasises the electric side of the car, that’s for sure.

And apparently, owners of the pre-facelift i8 told BMW they wanted even more electric running. So, for the update, the i8 gets a new battery pack that is more energy dense, gross energy capacity rising from 7.1 to 11.6kWh.

At the same time, the electric motor receives a power increase, up 9kW to 105kW (along with 250Nm of torque from rest as before). This all allows the i8 to drive at increased speeds and for longer on electric power alone.

The maximum speed on batteries is now 120km/h, while the pure electric range is quoted as 55km for the Coupe and 53km for the Roadster.

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Driving force

As always, that motor drives the front wheels alone, through a two-speed gearbox, while there’s a 1.5-litre three-cylinder turbo engine behind the cabin bolted to a six-speed auto.

The engine’s peak output of 170kW is unchanged, but BMW says it has been tweaked to sound even sportier, while a particulate filter is also new.

To hear that engine in action, you need to select Sport mode, which is done by slotting the gear lever to the left. The digital instruments behind the bespoke steering wheel change to a red colour scheme and the i8 begins to live up to its sports car styling.

The engine is suddenly more audible, more of the time and though there’s a faint three-cylinder warble, it sounds more like a six with an interesting exhaust. And yeah, there’s some electronic sound augmentation going on, but that doesn’t stop it being a lot of fun.

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Chassis tricks too

In fact, BMW’s chassis guys took the introduction of the Roadster as an opportunity to finesse the i8’s driving dynamics, focusing on the power steering calibration, body stiffness, stability control and damping.

As before, it’s a selectable two-mode damping system, but the changes have had a notable effect on how the car drives.

The i8’s nose tended to bob about over bumps and never felt keyed into the road surface on the entry to a corner, but the new one feels far more dependable and, as a result, more fun.

There’s no unwanted friction in the steering, just smooth transition across the locks, while the i8 seems to use all its tyres to better effect than before, allowing you lean on it through and out of a corner with confidence, the car moving all apiece.

In Sport mode, if you turn off the DSC completely, the i8 even exhibits some torque vectoring on the exit of tighter corners, as the outside wheel over-speeds, resulting in a more rear-driven sensation than the original i8 ever had.

It never goes much further than that as the electric motor up front pulls the car away from the curve, but it’s a satisfying new facet to the i8’s dynamics.

On this occasion we didn’t get a chance to try the updated Coupe, but we’re told that the same measures were applied to it, even if the Roadster’s remit is a fraction softer and it weighs 60kg more.

The result is a car that is more of a blast than ever to drive, even if some do write it off as one for which a technical presentation is not required…

How much is the 2018 BMW i8 Roadster?
Price: TBC
On sale: July
Engine: 1.5-litre turbo-petrol three-cylinder and front-mounted electric motor
Output: 275kW/320Nm
Transmission: Six-speed automatic (plus two-speed automatic for electric motor)
Fuel: 2.0L/100km
CO2: 46g/km
Safety rating: N/A