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A420iPetrolvsB118dDiesel
  • MotorwayMotorwayRange and charging
  • PerformancePerformance0-100, top speed
  • ConsumptionConsumptionYearly cost
  • Specs420i · 118d

BMW 420i Convertible G22 vs BMW 118d F40: which is truly faster?

Simulated drag race 0 → 1,000 m in real time. Synchronised speed counters and stopwatch. Physics calibration on 7 manufacturer measurements.

saloon · 2021 vs 2020 · Methodology
BMWPetrolFaster

420i Convertible G22

184 hp · 300 Nm · 1,690 kg · 2021

VS
BMWDiesel

118d F40

150 hp · 350 Nm · 1,405 kg · 2020

Result · 0–100 km/h

ABMW 420i Convertible G22

8.14 s

Gap0.51 sin favour of 420i Convertible
BBMW 118d F40

8.65 s

Summary · Caralogy simulation
Measure420i Convertible G22118d F40Gap
0–100 km/h8.14 s8.65 s0.51 s · 420i Convertible G22
400 m standing start15.97 s16.41 s0.44 s · 420i Convertible G22
1,000 m standing start28.97 s29.83 s0.86 s · 420i Convertible G22
Top speed (electronically limited)236 km/h218 km/h18 km/h · 420i Convertible G22
Power-to-weight ratio9.18 kg/hp9.37 kg/hpbetter ratio · 420i Convertible G22

Watch the race

Standing-start drag race, calibrated on manufacturer splits. The gap shows at each stage.

BMWPetrol420i Convertible G22
Speed
0km/h
Timer
0,00s
Distance
0m
BMWDiesel118d F40
Speed
0km/h
Timer
0,00s
Distance
0m
100 m
200 m
300 m
400 m
500 m
600 m
700 m
800 m
900 m
1000 m
0m → 1000m
Gap0m

Stage-by-stage comparison

Simulated performance at each stage. Best value in bold.
Stage420i Convertible G22118d F40
0–30 km/h1.81 s2.07 s
0–50 km/h3.07 s3.39 s
0–80 km/h5.69 s6.08 s
0–100 km/h8.14 s8.65 s
0–120 km/h11.24 s11.98 s
0–160 km/h20.26 s22.37 s
0–200 km/h36.93 s47.11 s
400 m standing start15.97 s16.41 s
1,000 m standing start28.97 s29.83 s
Top speed236 km/h218 km/h

Parameters and assumptions

Simulation

Start
Standing, straight line
Surface
Dry asphalt, 23°C
Wind
None
Driver
1 person, 75 kg

Calibration

Splits
0–100, 0–200 manufacturer
Power curve
Real measurement (Caralogy)
VMax
Manufacturer limited
Transmission
Losses integrated in model

Physics model calibrated on manufacturer splits. The limited top speed is not the real aerodynamic top speed of the vehicles.

Under the bonnet

Manufacturer technical specifications. The power-to-weight ratio is the key physical factor in a drag race.

BMW

420i Convertible G22

9,18kg/hpratio better by 0,18 kg/hp
CharacteristicValueDetail
Power184 hp4 cyl
Torque300 Nm
Weight1 690 kgmanufacturer kerb weight
Drivetrain-
GearboxEight-speed Steptronic transmission
BMW

118d F40

9,37kg/hpcompensated by −285 kg
CharacteristicValueDetail
Power150 hp4 cyl
Torque350 Nm
Weight1 405 kgmanufacturer kerb weight
Drivetrain-
GearboxSix-speed manual (8-speed Steptronic transmission)

The start: 0 to 100 km/h

Off the line, the 420i Convertible hits 100 km/h in 8.14 s versus 8.65 s for the 118d. At this point, the 420i Convertible leads by 0.51 s and sits roughly 8 m ahead.

From 100 km/h to 400 metres

At 200 metres, the 420i Convertible is doing 115 km/h against 113 km/h for the 118d. The gap is 0.33 s. The challenger starts to claw back ground.

At 400 metres standing start, the 420i Convertible crosses the line in 15.96 s versus 16.41 s. The 0.44 s gap represents roughly 17 m of track - two to three car lengths.

Beyond 400 metres: top speed comes into play

Past 400 metres, the 420i Convertible continues to build its lead. At 600 metres, it runs at 161 km/h versus 157 km/h. At 1,000 metres, the 420i Convertible finishes in 28.97 s versus 29.82 s, with a 0.86 s lead.

What the numbers don’t tell you

Both rivals are electronically governed, but not at the same level: the 420i Convertible is capped at 236 km/h, the 118d at 218 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 (9.18 kg/hp vs 9.37 kg/hp) and transmission (Automatic vs Automatic).

In European road use (130 km/h max), both vehicles reach the legal speed limit in under 14.03 seconds. The 0.51 s difference in 0 to 100 km/h is mostly felt in motorway merging and overtaking.

Other duels you might be interested in

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Frequently asked questions

Over 0–100 km/h, 420i Convertible G22 wins (8,14 s vs 8,65 s).

420i Convertible G22 goes from 0 to 100 km/h in 8,14 seconds (calibrated simulation).

420i Convertible G22: 184 hp, ratio 9,18 kg/hp. 118d F40: 150 hp, ratio 9,37 kg/hp.

420i Convertible G22: 236 km/h. 118d F40: 218 km/h.