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  • Specs840i · 718

BMW 840i G15 vs Porsche 718 Cayman: 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.

limousine · 2020 vs 2018 · Methodology
BMWPetrol

840i G15

340 hp · 500 Nm · 1,710 kg · 2020

VS
PorschePetrolFaster

718 Cayman

300 hp · 380 Nm · 1,335 kg · 2018

Result · 0–100 km/h

ABMW 840i G15

4.95 s

Gap0.39 sin favour of 718 Cayman
BPorsche 718 Cayman

4.56 s

Summary · Caralogy simulation
Measure840i G15718 CaymanGap
0–100 km/h4.95 s4.56 s0.39 s · 718 Cayman
400 m standing start13.16 s12.66 s0.50 s · 718 Cayman
1,000 m standing start23.75 s22.89 s0.86 s · 718 Cayman
Top speed (electronically limited)250 km/h274 km/h24 km/h · 718 Cayman
Power-to-weight ratio5.03 kg/hp4.45 kg/hpbetter ratio · 718 Cayman

Watch the race

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

BMWPetrol840i G15
Speed
0km/h
Timer
0,00s
Distance
0m
PorschePetrol718 Cayman
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.
Stage840i G15718 Cayman
0–30 km/h1.33 s1.28 s · tight gap
0–50 km/h2.23 s2.13 s · tight gap
0–80 km/h3.66 s3.50 s
0–100 km/h4.95 s4.56 s
0–120 km/h6.53 s5.89 s
0–160 km/h10.83 s9.50 s
0–200 km/h17.36 s15.19 s
400 m standing start13.16 s12.66 s
1,000 m standing start23.75 s22.89 s
Top speed limited250 km/h274 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

840i G15

5,03kg/hpcompensated by −375 kg
CharacteristicValueDetail
Power340 hp6 cyl
Torque500 Nm
Weight1 710 kgmanufacturer kerb weight
Drivetrain-
Gearbox8-speed Steptronic
Porsche

718 Cayman

4,45kg/hpratio better by 0,58 kg/hp
CharacteristicValueDetail
Power300 hpB4
Torque380 Nm
Weight1 335 kgmanufacturer kerb weight
DrivetrainPropulsion
GearboxDUAL_CLUTCH

The start: 0 to 100 km/h

Off the line, the 718 Cayman hits 100 km/h in 4.56 s versus 4.95 s for the 840i. At this point, the 718 Cayman leads by 0.39 s and sits roughly 3 m ahead.

From 100 km/h to 400 metres

At 200 metres, the 718 Cayman is doing 149 km/h against 142 km/h for the 840i. The gap is 0.29 s. The gap remains stable from the start.

At 400 metres standing start, the 718 Cayman crosses the line in 12.65 s versus 13.15 s. The 0.50 s gap represents roughly 24 m of track - two to three car lengths.

Beyond 400 metres: top speed comes into play

Past 400 metres, the 718 Cayman continues to build its lead. At 600 metres, it runs at 206 km/h versus 198 km/h. At 1,000 metres, the 718 Cayman finishes in 22.89 s versus 23.75 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 840i is capped at 250 (i.e. 155 mph - industry threshold) km/h, the 718 Cayman at 274 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 (5.03 kg/hp vs 4.45 kg/hp) and transmission (Automatic vs Automatic).

In European road use (130 km/h max), both vehicles reach the legal speed limit in under 7.46 seconds. The 0.39 s difference in 0 to 100 km/h is mostly felt in motorway merging and overtaking.

Compare with other alternatives

Swap one of the two models to explore an equivalent duel in the same segment.

Instead of 840i G15
Jaguar F-TYPE P300

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Frequently asked questions

Over 0–100 km/h, 718 Cayman wins (4,56 s vs 4,95 s).

840i G15 goes from 0 to 100 km/h in 4,95 seconds (calibrated simulation).

840i G15: 340 hp, ratio 5,03 kg/hp. 718 Cayman: 300 hp, ratio 4,45 kg/hp.

840i G15: 250 km/h. 718 Cayman: 274 km/h.