Porsche Cayenne S (8-speed Tiptronic S) 958.1 vs Bmw 840i xDrive Convertible G15 : which one is faster?
0-100 km/h, 400 m, 1000 m, top speed — physics simulation calibrated on 7 measures.
Simulation de performance
Race simulation at real speed
CONFIDENCE 90%Calibrated physics simulation: SCx via VMax, power curves, Crr via WLTP, drivetrain losses. Manufacturer 0-100 is the calibration target. Confidence 90 %.
Cayenne S (8-speed Tiptronic S) vs Bmw 840i xDrive Convertible: chronicle of a drag race at 258 km/h
The launch: 0 to 100 km/h
Off the line, the Bmw 840i xDrive Convertible hits 100 km/h in 5.30 s versus 5.81 s for the Cayenne S (8-speed Tiptronic S). At this point, the Bmw 840i xDrive Convertible leads by 0.51 s and sits roughly 5 m ahead.
From 100 km/h to 400 metres
At 200 metres, the Bmw 840i xDrive Convertible is doing 136 km/h against 133 km/h for the Cayenne S (8-speed Tiptronic S). The gap is 0.30 s. The challenger starts to claw back ground.
At 400 metres standing start, the Bmw 840i xDrive Convertible crosses the line in 13.56 s versus 13.99 s. The 0.42 s gap represents roughly 19 m of track — two to three car lengths.
Beyond 400 metres: top speed comes into play
Past 400 metres, the Bmw 840i xDrive Convertible continues to build its lead. At 600 metres, it runs at 190 km/h versus 186 km/h. At 1,000 metres, the Bmw 840i xDrive Convertible finishes in 24.59 s versus 25.30 s, with a 0.71 s lead. Both vehicles have similar top speeds (258 vs 250 km/h), preventing any comeback.
What the numbers don’t tell you
Both rivals are electronically governed, but not at the same level: the Cayenne S (8-speed Tiptronic S) is capped at 258 km/h, the Bmw 840i xDrive Convertible at 250 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.
With two combustion powertrains, the difference comes down to power-to-weight ratio (5.16 kg/hp vs 5.75 kg/hp) and transmission (Automatic vs Automatic).
In European road use (130 km/h max), both vehicles reach the legal speed limit in under 8.88 seconds. The 0.51 s difference in 0 to 100 km/h is mostly felt in motorway merging and overtaking.
Bmw 840i xDrive Convertible has a clear edge over the Porsche Cayenne S (8-speed Tiptronic S) to 100 km/h. This difference is clearly noticeable in spirited driving and widens on standing starts.