Car comparison

BMW 4 Series Convertible (G23) 420dvsBMW 4 Series Gran Coupe (G26) 420i

Compare specs, acceleration, fuel consumption, dimensions, practicality, and estimated running costs side by side.

New comparison

BMW 4 Series Convertible (G23)

420d

190 hp1995 ccDieselRWDAutomaticTurbochargedCabriolet / convertible2020-2024
VS

BMW 4 Series Gran Coupe (G26)

420i

184 hp1998 ccGasolineRWDAutomaticTurbochargedCoupe2021-2024

Comparison overview

Use the estimates as comparison hints and verify exact figures before making decisions.

Best choices

BMW 4 Series Convertible (G23) 420d

  • Quickest 0-100 km/h
    7.6 s
  • Fastest top speed
    236 km/h
    147 mph
  • Most powerful
    190 hp
    142 kW
  • Highest torque
    400 Nm
    295 lb-ft
  • Lowest combined fuel consumption
    4.5 L/100 km
    52.3 mpg US
    62.8 mpg UK
  • Best estimated range
    1,311 km
    815 mi
  • Best performance score
    52/100
  • Best economy score
    95/100

BMW 4 Series Gran Coupe (G26) 420i

  • Lightest
    1,620 kg
    3,571 lb
  • Best power-to-weight
    114 hp/t
    85 kW/t
    8.8 kg/hp
  • Largest trunk
    470 L
  • Best overall score
    55/100
  • Best practicality score
    69/100

Specification comparison

Specification comparison
ModelBMW4 Series Convertible (G23)420dBMW4 Series Gran Coupe (G26)420i
Power
190hp142kW
184hp137kW
Torque
400Nm295lb-ft
300Nm221lb-ft
Curb weight
1,775kg3,913lb
1,620kg3,571lb
Gross weight
2,270kg5,004lb
2,175kg4,795lb
Top speed
236 km/h
147 mph
235 km/h
146 mph
To 99% top speed
99.3s99% target: 234 km/h / 145 mph
Calculated
99.3s99% target: 233 km/h / 145 mph
Calculated
0-100 km/h
7.6s
7.9s
0-200 km/h
33.6s
Calculated
34.6s
Calculated
0-60 mph
7.2s
Calculated
7.5s
Calculated
Fuel consumption
4.5L/100 km52.3mpg US62.8mpg UK
7.3L/100 km32.2mpg US38.7mpg UK
Fuel consumption city
5L/100 km47mpg US56.5mpg UK
-
Fuel consumption highway
4.3L/100 km54.7mpg US65.7mpg UK
-
Quarter mile
15.5s
Calculated
15.7s
Calculated
Power-to-weight
107hp/t80kW/t49hp/1000 lb
Calculated
114hp/t85kW/t52hp/1000 lb
Calculated
Torque-to-weight
225Nm/t151lb-ft/ton
Calculated
185Nm/t124lb-ft/ton
Calculated
Estimated range
1,311km815mi
Calculated
808km502mi
Calculated
Displacement
1,995cc122cu in
1,998cc122cu in
Length
4,768mm188in
4,783mm188in
Width
1,852mm73in
1,852mm73in
Height
1,384mm54in
1,442mm57in
Wheelbase
2,851mm112in
2,856mm112in
Front track
1,575mm62in
1,595mm63in
Rear track
1,611mm63in
1,623mm64in
Ground clearance
124mm5in
140mm6in
Trunk volume
300L
470L
Max trunk volume
385L
1,290L
Doors
2
5
Seats
4
5
Fuel tank
59L
59L

Performance charts

Use the estimates as comparison hints and verify exact figures before making decisions.

Dyno simulation

Estimated stock-style power and torque curves by engine speed.

BMW 4 Series Convertible (G23) 420dBMW 4 Series Gran Coupe (G26) 420iPowerTorque
  • BMW 4 Series Convertible (G23) 420d: Power / Torque
  • BMW 4 Series Gran Coupe (G26) 420i: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
BMW4 Series Convertible (G23)420d4,000 rpm1,750-2,500 rpm4,250 rpm
BMW4 Series Gran Coupe (G26)420i5,000-6,500 rpm1,350-4,000 rpm6,750 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW4 Series Convertible (G23)420dBMW4 Series Gran Coupe (G26)420i
Acceleration checkpoints
0-60 mph
0-97 km/h
7.2 s
7.5 s
0-100 km/h
0-62 mph
7.6 s
7.9 s
0-200 km/h
0-124 mph
33.6 s
34.6 s
Top speed
236 km/h
147 mph
235 km/h
146 mph
Drag race simulation
60 ft
18 m
2.5 s
2.6 s
330 ft
101 m
6.7 s
6.8 s
1/8 mile
201 m
10.1 s
10.3 s
1000 ft
305 m
13.0 s
13.2 s
1/4 mile
402 m
15.5 s
15.7 s
Trap speed
1/4 mile
402 m
148 km/h
92 mph
147 km/h
91 mph

Power comparison

Bar comparison chart for Power. Higher is better · hp / kW

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
190 hp
142 kW
BMW4 Series Gran Coupe (G26)420i
184 hp
137 kW

BMW 4 Series Convertible (G23) 420d has 6 hp more than BMW 4 Series Gran Coupe (G26) 420i.

The biggest power difference is between BMW 4 Series Gran Coupe (G26) 420i and BMW 4 Series Convertible (G23) 420d: 6 hp (4 kW).

Torque comparison

Bar comparison chart for Torque. Higher is better · Nm / lb-ft

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
400 Nm
295 lb-ft
BMW4 Series Gran Coupe (G26)420i
300 Nm
221 lb-ft

Curb weight comparison

Bar comparison chart for Curb weight. Lower is better · kg / lb

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
1,775 kg
3,913 lb
BMW4 Series Gran Coupe (G26)420i
1,620 kg
3,571 lb

Top speed without limiter comparison

Bar comparison chart for Top speed without limiter. Higher is better · km/h / mph

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
236 km/h
147 mph
BMW4 Series Gran Coupe (G26)420i
235 km/h
146 mph

0-100 km/h comparison

Bar comparison chart for 0-100 km/h. Lower is better · seconds

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d7.6 s
BMW4 Series Gran Coupe (G26)420i7.9 s

The biggest 0-100 km/h difference is between BMW 4 Series Convertible (G23) 420d and BMW 4 Series Gran Coupe (G26) 420i: 0.3 s.

Fuel consumption comparison

Bar comparison chart for Fuel consumption. Lower is better · L/100 km / mpg US / mpg UK

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
BMW4 Series Gran Coupe (G26)420i
7.3 L/100 km
32.2 mpg US
38.7 mpg UK

The biggest fuel consumption difference is between BMW 4 Series Convertible (G23) 420d and BMW 4 Series Gran Coupe (G26) 420i: 2.8 L/100 km.

Power-to-weight comparison

Bar comparison chart for Power-to-weight. Higher is better · hp/t / kW/t

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
107 hp/t
80 kW/t
9.3 kg/hp
BMW4 Series Gran Coupe (G26)420i
114 hp/t
85 kW/t
8.8 kg/hp

Estimated range comparison

Bar comparison chart for Estimated range. Higher is better · km / mi

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
1,311 km
815 mi
BMW4 Series Gran Coupe (G26)420i
808 km
502 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
BMW4 Series Convertible (G23)420d
190 hp
142 kW
7.6 s
236 km/h
147 mph
BMW4 Series Gran Coupe (G26)420i
184 hp
137 kW
7.9 s
235 km/h
146 mph

Most attractive quadrant

Scatter chart with performance score on the X axis and practicality score on the Y axis.

Chart data table
VehiclePerformance scorePracticality score
BMW4 Series Convertible (G23)420d
Power
190 hp
142 kW
0-100 km/h7.6 s
Top speed
236 km/h
147 mph
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,768 mm
187.7 in
Height
1,384 mm
54.5 in
BMW4 Series Gran Coupe (G26)420i
Power
184 hp
137 kW
0-100 km/h7.9 s
Top speed
235 km/h
146 mph
Doors/seats
5 doors
5 seats
Trunk
470 L
16.6 cu ft
Length
4,783 mm
188.3 in
Height
1,442 mm
56.8 in

Performance vs fuel economy

Cars closer to the top-right corner combine stronger performance with better fuel economy scores.

Performance vs fuel economy data table
VehiclePerformance scoreFuel economy score
BMW4 Series Convertible (G23)420d
Power
190 hp
142 kW
0-100 km/h7.6 s
Top speed
236 km/h
147 mph
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
BMW4 Series Gran Coupe (G26)420i
Power
184 hp
137 kW
0-100 km/h7.9 s
Top speed
235 km/h
146 mph
7.3 L/100 km
32.2 mpg US
38.7 mpg UK

BMW 4 Series Convertible (G23) 420d is closest to the top-right balance target for performance and fuel economy.

Acceleration vs fuel consumption

Cars closer to the lower-left corner offer a better mix of quick acceleration and low fuel consumption.

Acceleration vs fuel consumption data table
VehicleFuel consumption, L/100 km0-100 km/h, s
BMW4 Series Convertible (G23)420d
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
7.6 s
BMW4 Series Gran Coupe (G26)420i
7.3 L/100 km
32.2 mpg US
38.7 mpg UK
7.9 s

Power-to-weight vs fuel consumption

The shaded area favors higher power-to-weight with lower combined fuel consumption.

Power-to-weight vs fuel consumption data table
VehiclePower-to-weight, hp/tFuel consumption, L/100 km
BMW4 Series Convertible (G23)420d
107 hp/t
80 kW/t
9.3 kg/hp
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
BMW4 Series Gran Coupe (G26)420i
114 hp/t
85 kW/t
8.8 kg/hp
7.3 L/100 km
32.2 mpg US
38.7 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMW4 Series Convertible (G23)420dBMW4 Series Gran Coupe (G26)420i
Power
190 hp
142 kW
184 hp
137 kW
Torque
400 Nm
295 lb-ft
300 Nm
221 lb-ft
Acceleration
7.6 s
7.9 s
Top speed
236 km/h
147 mph
235 km/h
146 mph
Lightness
1,775 kg
3,913 lb
1,620 kg
3,571 lb
Fuel consumption
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
7.3 L/100 km
32.2 mpg US
38.7 mpg UK
Practicality
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,768 mm
187.7 in
Height
1,384 mm
54.5 in
Doors/seats
5 doors
5 seats
Trunk
470 L
16.6 cu ft
Length
4,783 mm
188.3 in
Height
1,442 mm
56.8 in
Range score
1,311 km
815 mi
808 km
502 mi
Trunk score
300 L
10.6 cu ft
470 L
16.6 cu ft
Power-to-weight score
107 hp/t
80 kW/t
9.3 kg/hp
114 hp/t
85 kW/t
8.8 kg/hp
Overall
Fixed score
Fixed score

Fuel cost and annual usage

Estimate running costs from combined consumption, your annual distance, and the fuel price in your local currency.

Enter the fuel price in your local currency, for example €/L, $/gal, £/L or any other local currency.

LC = Local Currency

Fuel cost and annual usage
VehicleBMW 4 Series Convertible (G23) 420dBMW 4 Series Gran Coupe (G26) 420i
Consumption4.5 L/100 km52.3 mpg US62.8 mpg UK7.3 L/100 km32.2 mpg US38.7 mpg UK
Cost / 100 km7.88 LC100 km12.78 LC100 km
Cost / 100 mi12.67 LC100 mi20.56 LC100 mi
Annual fuel used675 L178 US gal148 UK gal1,095 L289 US gal241 UK gal
Annual fuel cost1,181 LC/year1,916 LC/year

Head-to-head comparisons

BMW 4 Series Convertible (G23) 420d

  • Has 6 hp more
  • Has 100 Nm more
  • Is 0.3 s quicker from 0-100 km/h
  • Has 1 km/h (1 mph) higher top speed
  • Uses 2.8 L/100 km less fuel
  • Has 503 km (312 mi) more estimated range

Pros

  • Quickest 0-100 km/h in this comparison
  • Highest top speed
  • Most powerful
  • Highest torque
  • Lowest combined fuel consumption
  • Best estimated range

Cons

  • Heaviest
  • Smallest trunk

BMW 4 Series Gran Coupe (G26) 420i

  • Is 155 kg lighter
  • Has 7 hp/t better power-to-weight
  • Has 170 L more trunk volume

Pros

  • Lightest
  • Best power-to-weight ratio
  • Largest trunk

Cons

  • Slowest 0-100 km/h
  • Lowest power
  • Highest combined fuel consumption
  • Lowest top speed

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW 4 Series Convertible (G23) 420d
BMW 4 Series Gran Coupe (G26) 420i
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