BMW 420d Convertible G22 vs BMW i3 I01: which is truly faster?

Off the line, the i3 hits 100 km/h in 7.24 s versus 7.75 s for the 420d Convertible. The instant torque of 250 Nm from the electric motor makes the difference. Despite the faster sprint time, the 420d Convertible is 5 m further along the track at this moment: stronger low-speed acceleration offsets a slower run beyond 100 km/h.

At 200 metres, the 420d Convertible is doing 116 km/h against 122 km/h for the i3. The gap is 0.03 s. The challenger starts to claw back ground.

At 400 metres standing start, the i3 crosses the line in 15.40 s versus 15.64 s. The 0.24 s gap represents roughly 10 m of track - barely a car length.

Past 400 metres, the situation changes. The i3 maxes out at 150 km/h while the 420d Convertible keeps accelerating towards 236 km/h. At 600 metres, the gap has dropped to 0.17 s.

Around 682 metres, both vehicles are level. This is the inversion point: the 420d Convertible overcomes its launch deficit thanks to a 86 km/h higher top speed.

At 1,000 metres, the 420d Convertible finishes in 28.69 s versus 29.80 s. The 1.11 s delta in favour of the 420d Convertible shows that top speed makes a clear difference.

Both rivals are electronically governed, but not at the same level: the 420d Convertible is capped at 236 km/h, the i3 at 150 km/h. This isn’t a physical engine limit - it’s a manufacturer choice, usually for tyre safety or homologation reasons. Neither car reaches its true aerodynamic top speed.

Instant electric torque gives an advantage off the line. The higher top speed of the combustion engine gives an advantage over longer distances. The distance at which one catches the other depends on the top speed differential.

In European road use (130 km/h max), both vehicles reach the legal speed limit in under 12.82 seconds. The 0.51 s difference in 0 to 100 km/h is mostly felt in motorway merging and overtaking.