Porsche Cayenne S (8-speed Tiptronic S) 958.1 vs Bmw 840i 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 Convertible: chronicle of a drag race at 258 km/h
The launch: 0 to 100 km/h
Off the line, the Bmw 840i Convertible hits 100 km/h in 5.57 s versus 5.81 s for the Cayenne S (8-speed Tiptronic S). The 0.24 s gap is negligible: both vehicles are neck and neck.
From 100 km/h to 400 metres
At 200 metres, the Bmw 840i Convertible is doing 136 km/h against 133 km/h for the Cayenne S (8-speed Tiptronic S). The gap is 0.08 s. The challenger starts to claw back ground.
At 400 metres standing start, the Bmw 840i Convertible crosses the line in 13.79 s versus 13.99 s. The 0.20 s gap represents roughly 9 m of track — barely a car length.
Beyond 400 metres: top speed comes into play
Past 400 metres, the Bmw 840i 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 Convertible finishes in 24.82 s versus 25.30 s, with a 0.48 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 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 5.53 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 0.24 s difference in 0 to 100 km/h is mostly felt in motorway merging and overtaking.
Bmw 840i Convertible is slightly faster than the Porsche Cayenne S (8-speed Tiptronic S) to 100 km/h. The edge holds on standing starts but may narrow at higher speeds depending on aerodynamic load.