Porsche 911 Turbo S Cabriolet 991.2 vs Alfa Romeo Giulia Quadrifoglio : which one is faster?
0-100 km/h, 400 m, 1000 m, top speed — physics simulation calibrated on 7 measures.
400 mSimulation de performance
Race simulation at real speed
CONFIDENCE 91%Calibrated physics simulation: SCx via VMax, power curves, Crr via WLTP, drivetrain losses. Manufacturer 0-100 is the calibration target. Confidence 91 %.
911 Turbo S Cabriolet vs Giulia Quadrifoglio: chronicle of a drag race at 329 km/h
The launch: 0 to 100 km/h
Off the line, the 911 Turbo S Cabriolet hits 100 km/h in 2.95 s versus 3.94 s for the Giulia Quadrifoglio. At this point, the 911 Turbo S Cabriolet leads by 0.99 s and sits roughly 11 m ahead.
From 100 km/h to 400 metres
At 200 metres, the 911 Turbo S Cabriolet is doing 176 km/h against 164 km/h for the Giulia Quadrifoglio. The gap is 0.89 s. The challenger starts to claw back ground.
At 400 metres standing start, the 911 Turbo S Cabriolet crosses the line in 10.56 s versus 11.74 s. The 1.18 s gap represents roughly 65 m of track — a gap visible to the naked eye.
Beyond 400 metres: top speed comes into play
Past 400 metres, the 911 Turbo S Cabriolet continues to build its lead. At 600 metres, it runs at 246 km/h versus 228 km/h. At 1,000 metres, the 911 Turbo S Cabriolet finishes in 19.13 s versus 20.93 s, with a 1.80 s lead.
What the numbers don’t tell you
Both rivals are electronically governed, but not at the same level: the 911 Turbo S Cabriolet is capped at 330 km/h, the Giulia Quadrifoglio at 307 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 (2.84 kg/hp vs 3.10 kg/hp) and transmission (Automatic vs Automatic).
In European road use (130 km/h max), both vehicles reach the legal speed limit in under 5.51 seconds. The 0.99 s difference in 0 to 100 km/h is mostly felt in motorway merging and overtaking.
Porsche 911 Turbo S Cabriolet has a clear edge over the Alfa Romeo Giulia Quadrifoglio to 100 km/h. This difference is clearly noticeable in spirited driving and widens on standing starts.