Car comparison

BMW 6 Series Convertible (E64) 645CivsBMW 6 Series (E24) 635CSi

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

New comparison

BMW 6 Series Convertible (E64)

645Ci

333 hp4398 ccGasolineRWDAutomaticNaturally aspiratedCabriolet / convertible2003-2005
VS

BMW 6 Series (E24)

635CSi

218 hp3453 ccGasolineRWDManualNaturally aspiratedCoupe1978-1982

Comparison overview

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

Best choices

BMW 6 Series Convertible (E64) 645Ci

  • Quickest 0-100 km/h
    6.2 s
  • Fastest top speed
    260 km/h
    162 mph Unrestricted
    250 km/h
    155 mph Restricted
  • Most powerful
    333 hp
    248 kW
  • Highest torque
    450 Nm
    332 lb-ft
  • Best power-to-weight
    183 hp/t
    136 kW/t
    5.5 kg/hp
  • Best overall score
    59/100
  • Best performance score
    65/100

BMW 6 Series (E24) 635CSi

  • Lightest
    1,500 kg
    3,307 lb
  • Lowest combined fuel consumption
    10.0 L/100 km
    23.5 mpg US
    28.2 mpg UK
  • Best estimated range
    700 km
    435 mi
  • Largest trunk
    415 L
  • Best economy score
    80/100
  • Best practicality score
    52/100

Specification comparison

Specification comparison
ModelBMW6 Series Convertible (E64)645CiBMW6 Series (E24)635CSi
Power
333hp248kW
218hp163kW
Torque
450Nm332lb-ft
310Nm229lb-ft
Curb weight
1,820kg4,012lb
1,500kg3,307lb
Gross weight
2,220kg4,894lb
1,860kg4,101lb
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Calculated
222 km/h
138 mph
To 99% top speed
87.8s99% target: 257 km/h / 160 mph
Calculated
94.9s99% target: 220 km/h / 137 mph
Calculated
0-100 km/h
6.2s
7.6s
0-200 km/h
22.8s
Calculated
40.5s
Calculated
0-60 mph
5.9s
Calculated
7.2s
Calculated
Fuel consumption
11.5L/100 km20.5mpg US24.6mpg UK
10L/100 km23.5mpg US28.2mpg UK
Fuel consumption city
16.8L/100 km14mpg US16.8mpg UK
-
Fuel consumption highway
8.5L/100 km27.7mpg US33.2mpg UK
-
Quarter mile
14.3s
Calculated
15.5s
Calculated
Power-to-weight
183hp/t136kW/t83hp/1000 lb
Calculated
145hp/t108kW/t66hp/1000 lb
Calculated
Torque-to-weight
247Nm/t165lb-ft/ton
Calculated
207Nm/t138lb-ft/ton
Calculated
Estimated range
609km378mi
Calculated
700km435mi
Calculated
Displacement
4,398cc268cu in
3,453cc211cu in
Length
4,820mm190in
4,755mm187in
Width
1,855mm73in
1,725mm68in
Height
1,373mm54in
1,365mm54in
Wheelbase
2,780mm109in
2,626mm103in
Front track
1,558mm61in
1,422mm56in
Rear track
1,592mm63in
1,487mm59in
Trunk volume
300L
415L
Max trunk volume
350L
-
Doors
2
2
Seats
4
4
Fuel tank
70L
70L

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 6 Series Convertible (E64) 645CiBMW 6 Series (E24) 635CSiPowerTorque
  • BMW 6 Series Convertible (E64) 645Ci: Power / Torque
  • BMW 6 Series (E24) 635CSi: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
BMW6 Series Convertible (E64)645Ci6,100 rpm3,600 rpm6,350 rpm
BMW6 Series (E24)635CSi5,200 rpm4,000 rpm5,450 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW6 Series Convertible (E64)645CiBMW6 Series (E24)635CSi
Acceleration checkpoints
0-60 mph
0-97 km/h
5.9 s
7.2 s
0-100 km/h
0-62 mph
6.2 s
7.6 s
0-200 km/h
0-124 mph
22.8 s
40.5 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Likely limited
222 km/h
138 mph
Drag race simulation
60 ft
18 m
2.4 s
2.4 s
330 ft
101 m
6.2 s
6.6 s
1/8 mile
201 m
9.3 s
10.0 s
1000 ft
305 m
12.0 s
13.0 s
1/4 mile
402 m
14.3 s
15.5 s
Trap speed
1/4 mile
402 m
163 km/h
101 mph
146 km/h
90 mph

Power comparison

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

Chart data table
VehicleValue
BMW6 Series Convertible (E64)645Ci
333 hp
248 kW
BMW6 Series (E24)635CSi
218 hp
163 kW

BMW 6 Series Convertible (E64) 645Ci has 115 hp more than BMW 6 Series (E24) 635CSi.

The biggest power difference is between BMW 6 Series (E24) 635CSi and BMW 6 Series Convertible (E64) 645Ci: 115 hp (86 kW).

Torque comparison

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

Chart data table
VehicleValue
BMW6 Series Convertible (E64)645Ci
450 Nm
332 lb-ft
BMW6 Series (E24)635CSi
310 Nm
229 lb-ft

Curb weight comparison

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

Chart data table
VehicleValue
BMW6 Series Convertible (E64)645Ci
1,820 kg
4,012 lb
BMW6 Series (E24)635CSi
1,500 kg
3,307 lb

Top speed without limiter comparison

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

Chart data table
VehicleValue
BMW6 Series Convertible (E64)645Ci
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
BMW6 Series (E24)635CSi
222 km/h
138 mph

0-100 km/h comparison

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

Chart data table
VehicleValue
BMW6 Series Convertible (E64)645Ci6.2 s
BMW6 Series (E24)635CSi7.6 s

The biggest 0-100 km/h difference is between BMW 6 Series Convertible (E64) 645Ci and BMW 6 Series (E24) 635CSi: 1.4 s.

Fuel consumption comparison

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

Chart data table
VehicleValue
BMW6 Series Convertible (E64)645Ci
11.5 L/100 km
20.5 mpg US
24.6 mpg UK
BMW6 Series (E24)635CSi
10.0 L/100 km
23.5 mpg US
28.2 mpg UK

The biggest fuel consumption difference is between BMW 6 Series (E24) 635CSi and BMW 6 Series Convertible (E64) 645Ci: 1.5 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
BMW6 Series Convertible (E64)645Ci
183 hp/t
136 kW/t
5.5 kg/hp
BMW6 Series (E24)635CSi
145 hp/t
108 kW/t
6.9 kg/hp

Estimated range comparison

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

Chart data table
VehicleValue
BMW6 Series Convertible (E64)645Ci
609 km
378 mi
BMW6 Series (E24)635CSi
700 km
435 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
BMW6 Series Convertible (E64)645Ci
333 hp
248 kW
6.2 s
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
BMW6 Series (E24)635CSi
218 hp
163 kW
7.6 s
222 km/h
138 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
BMW6 Series Convertible (E64)645Ci
Power
333 hp
248 kW
0-100 km/h6.2 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
BMW6 Series (E24)635CSi
Power
218 hp
163 kW
0-100 km/h7.6 s
Top speed
222 km/h
138 mph
Doors/seats
2 doors
4 seats
Trunk
415 L
14.7 cu ft
Length
4,755 mm
187.2 in
Height
1,365 mm
53.7 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
BMW6 Series Convertible (E64)645Ci
Power
333 hp
248 kW
0-100 km/h6.2 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
11.5 L/100 km
20.5 mpg US
24.6 mpg UK
BMW6 Series (E24)635CSi
Power
218 hp
163 kW
0-100 km/h7.6 s
Top speed
222 km/h
138 mph
10.0 L/100 km
23.5 mpg US
28.2 mpg UK

BMW 6 Series Convertible (E64) 645Ci 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
BMW6 Series Convertible (E64)645Ci
11.5 L/100 km
20.5 mpg US
24.6 mpg UK
6.2 s
BMW6 Series (E24)635CSi
10.0 L/100 km
23.5 mpg US
28.2 mpg UK
7.6 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
BMW6 Series Convertible (E64)645Ci
183 hp/t
136 kW/t
5.5 kg/hp
11.5 L/100 km
20.5 mpg US
24.6 mpg UK
BMW6 Series (E24)635CSi
145 hp/t
108 kW/t
6.9 kg/hp
10.0 L/100 km
23.5 mpg US
28.2 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMW6 Series Convertible (E64)645CiBMW6 Series (E24)635CSi
Power
333 hp
248 kW
218 hp
163 kW
Torque
450 Nm
332 lb-ft
310 Nm
229 lb-ft
Acceleration
6.2 s
7.6 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
222 km/h
138 mph
Lightness
1,820 kg
4,012 lb
1,500 kg
3,307 lb
Fuel consumption
11.5 L/100 km
20.5 mpg US
24.6 mpg UK
10.0 L/100 km
23.5 mpg US
28.2 mpg UK
Practicality
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
Doors/seats
2 doors
4 seats
Trunk
415 L
14.7 cu ft
Length
4,755 mm
187.2 in
Height
1,365 mm
53.7 in
Range score
609 km
378 mi
700 km
435 mi
Trunk score
300 L
10.6 cu ft
415 L
14.7 cu ft
Power-to-weight score
183 hp/t
136 kW/t
5.5 kg/hp
145 hp/t
108 kW/t
6.9 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 6 Series Convertible (E64) 645CiBMW 6 Series (E24) 635CSi
Consumption11.5 L/100 km20.5 mpg US24.6 mpg UK10 L/100 km23.5 mpg US28.2 mpg UK
Cost / 100 km20.13 LC100 km17.50 LC100 km
Cost / 100 mi32.39 LC100 mi28.16 LC100 mi
Annual fuel used1,725 L456 US gal379 UK gal1,500 L396 US gal330 UK gal
Annual fuel cost3,019 LC/year2,625 LC/year

Head-to-head comparisons

BMW 6 Series Convertible (E64) 645Ci

  • Has 115 hp more
  • Has 140 Nm more
  • Is 1.4 s quicker from 0-100 km/h
  • Has 38 km/h (24 mph) higher top speed
  • Has 38 hp/t better power-to-weight

Pros

  • Quickest 0-100 km/h in this comparison
  • Highest top speed
  • Most powerful
  • Highest torque
  • Best power-to-weight ratio

Cons

  • Highest combined fuel consumption
  • Heaviest
  • Smallest trunk

BMW 6 Series (E24) 635CSi

  • Is 320 kg lighter
  • Uses 1.5 L/100 km less fuel
  • Has 91 km (57 mi) more estimated range
  • Has 115 L more trunk volume

Pros

  • Lightest
  • Lowest combined fuel consumption
  • Best estimated range
  • Largest trunk

Cons

  • Slowest 0-100 km/h
  • Lowest power
  • Lowest top speed

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW 6 Series Convertible (E64) 645Ci
BMW 6 Series (E24) 635CSi
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