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BMW i3s with Range Extender

John Mengel

With the original i3 EV, BMW aimed to apply its engineering prowess in unconventional ways—not just with weight-saving construction techniques that mated a carbon-fiber composite passenger cell to a mostly aluminum chassis, but also with eco-friendly elements such as natural-fiber cabin finishes, leather seats tanned with an olive-oil extract, a key fob made of a castor-oil-based polymer, and hemp-reinforced interior plastics. The driving experience wasn’t exactly forgotten, but it played second fiddle to the feel-good sustainability overtures.

Fast forward nearly five years, and the present reality is that the i3’s sales have been well short of original expectations and downright lackluster in contrast to the rabid demand for the new Tesla Model 3 (BMW targeted Tesla with the original i3 launch). Munich’s answer to stoke interest, it seems, is to step back a bit and embrace traditional BMW dynamic virtues.

Thus the new-for-2018 i3s tested here. That lowercase s denotes some extra kick in the form of a higher-output motor—in this case, 184 horsepower and 199 lb-ft of torque, 14 ponies and 15 lb-ft more than in the standard i3. Wider tires, fender flares, and a lower ride height improve the curbside stance and hint at the stiffer suspension tune. Inside, drivers will find something that has been missing from the i3 lineup all along: a Sport mode. There’s an attractive facelift to many of the trims and surfaces, and our test car wore a coat of bright, purposeful, $550 Melbourne Red Metallic paint.

Not Ludicrous

After track testing and hundreds of miles of city and highway driving, we still won’t call this racier i3s exhilarating, but it is incrementally quicker (and faster) by the numbers and noticeably zippier from the driver’s seat. The i3s we tested was the REx version, which means it had the additional range-extending 38-hp, 647-cc two-cylinder engine tucked under the rear cargo floor. It weighs 274 pounds more than an i3s without the gasoline-fueled engine.

The power boost pares the zero-to-60-mph time to 6.8 seconds, versus 7.2 seconds for the last i3 REx we tested, a 2017 model. That’s still far from class-leading performance among EVs. The Chevrolet Bolt EV accelerates to 60 mph in 6.5 seconds, and the Tesla Model 3—not yet available in its highest-performance guise—needs only 5.1. But the i3s solidly outruns the latest Nissan Leaf (7.4 seconds) as well as the Volkswagen e-Golf. Keep in mind that i3 models without the range extender are quicker. Without the mass holding them back, we’ve seen the non-s i3 dash to 60 mph in 6.6 seconds, and an i3s clocked 6.3.

This 2018 i3s did the quarter-mile in 15.3 seconds at 93 mph, which is 1 mph faster than our observed top speed of the standard i3 REx. The i3s tops out at 100 mph by keeping the same gear ratio (there’s only one) but allowing a higher peak motor speed (11,900 rpm versus 11,400), with new tapered roller bearings for the motor. The tires are sized 175/55R-20 in front and 195/50R-20 out back, which are only large by comparison to the base model’s front 155/70R-19s and rear 175/60R-19s. They’re still Bridgestone Ecopias, engineered for low rolling resistance more than traction, but this car’s roadholding, measured at 0.84 g on the skidpad, was well beyond the 0.77 g of grip the standard i3 generates. (The e-Golf recorded 0.82 g.) Braking was a consistent—and consistently good—163 feet from 70 mph. That’s a huge improvement over the 184 feet it took to stop the 2017 i3 REx we tested, and it’s also much better than the 181-foot stops recorded by the VW e-Golf and Chevy Bolt.

As before, the i3 offers drivers the choice between Comfort, Eco Pro, and Eco Pro+ driving modes, but the i3s also adds the aforementioned Sport mode. The dampers aren’t adaptive, so this mode simply dials up a more aggressive tune for how the motor responds to the accelerator, and it also makes the steering slightly heavier. Given the overboosted nature of the steering in the other modes, this is where the calibration should have been all along.

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