Mercedes GLC 400 4MATIC with EQ Technology X254 vs BMW X4 M40i G02: which is truly faster?

Off the line, the GLC 400 4MATIC with EQ Technology hits 100 km/h in 4.34 s versus 4.75 s for the X4 M40i. The instant torque of 800 Nm from the electric motor makes the difference. At this point, the GLC 400 4MATIC with EQ Technology leads by 0.41 s and sits roughly 4 m ahead.

At 200 metres, the GLC 400 4MATIC with EQ Technology is doing 145 km/h against 142 km/h for the X4 M40i. The gap is 0.27 s. The challenger starts to claw back ground.

At 400 metres standing start, the GLC 400 4MATIC with EQ Technology crosses the line in 12.66 s versus 12.98 s. The 0.33 s gap represents roughly 16 m of track - two to three car lengths.

Past 400 metres, the gap narrows. The GLC 400 4MATIC with EQ Technology maxes out at 210 km/h while the X4 M40i keeps accelerating towards 250 (i.e. 155 mph - industry threshold) km/h. At 600 metres, the gap has dropped to 0.37 s.

At 1,000 metres, the GLC 400 4MATIC with EQ Technology finishes in 23.35 s versus 23.62 s, with just 0.27 s to spare. The X4 M40i fails to fully close the launch gap.

Both rivals are electronically governed, but not at the same level: the GLC 400 4MATIC with EQ Technology is capped at 210 km/h, the X4 M40i at 250 (i.e. 155 mph - industry threshold) 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 7.22 seconds. The 0.41 s difference in 0 to 100 km/h is mostly felt in motorway merging and overtaking.