Car comparison

BMW 6 Series (E63) 645CivsBMW 8 Series (E31) 850Ci 5.4

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

New comparison

BMW 6 Series (E63)

645Ci

333 hp4398 ccGasolineRWDAutomaticNaturally aspiratedCoupe2003-2005
VS

BMW 8 Series (E31)

850Ci 5.4

326 hp5379 ccGasolineRWDAutomaticNaturally aspiratedCoupe1994-1999

Comparison overview

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

Best choices

BMW 6 Series (E63) 645Ci

  • Quickest 0-100 km/h
    5.8 s
  • Fastest top speed
    265 km/h
    165 mph Unrestricted
    250 km/h
    155 mph Restricted
  • Most powerful
    333 hp
    248 kW
  • Lightest
    1,695 kg
    3,737 lb
  • Best power-to-weight
    196 hp/t
    147 kW/t
    5.1 kg/hp
  • Lowest city consumption
    16.1 L/100 km
    14.6 mpg US
    17.5 mpg UK
  • Lowest highway consumption
    8.0 L/100 km
    29.4 mpg US
    35.3 mpg UK
  • Largest trunk
    450 L
  • Best overall score
    63/100
  • Best performance score
    68/100
  • Best economy score
    78/100
  • Best practicality score
    53/100

Specification comparison

Specification comparison
ModelBMW6 Series (E63)645CiBMW8 Series (E31)850Ci 5.4
Power
333hp248kW
326hp243kW
Torque
450Nm332lb-ft
490Nm361lb-ft
Curb weight
1,695kg3,737lb
1,880kg4,145lb
Gross weight
2,065kg4,553lb
2,300kg5,071lb
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Calculated
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Calculated
To 99% top speed
79.6s99% target: 262 km/h / 163 mph
Calculated
90.9s99% target: 262 km/h / 163 mph
Calculated
0-100 km/h
5.8s
6.3s
0-200 km/h
20.3s
Calculated
22.6s
Calculated
0-60 mph
5.5s
Calculated
6.0s
Calculated
Fuel consumption
10.9L/100 km21.6mpg US25.9mpg UK
-
Fuel consumption city
16.1L/100 km14.6mpg US17.5mpg UK
21.1L/100 km11.1mpg US13.4mpg UK
Fuel consumption highway
8L/100 km29.4mpg US35.3mpg UK
9.9L/100 km23.8mpg US28.5mpg UK
Quarter mile
13.9s
Calculated
14.3s
Calculated
Power-to-weight
196hp/t147kW/t89hp/1000 lb
Calculated
173hp/t129kW/t79hp/1000 lb
Calculated
Torque-to-weight
265Nm/t178lb-ft/ton
Calculated
261Nm/t174lb-ft/ton
Calculated
Estimated range
642km399mi
Calculated
-
Displacement
4,398cc268cu in
5,379cc328cu in
Length
4,820mm190in
4,780mm188in
Width
1,855mm73in
1,855mm73in
Height
1,373mm54in
1,340mm53in
Wheelbase
2,780mm109in
2,684mm106in
Front track
1,558mm61in
1,554mm61in
Rear track
1,592mm63in
1,562mm61in
Trunk volume
450L
320L
Doors
2
2
Seats
4
4
Fuel tank
70L
90L
CO2 emissions
264g/km
-

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 (E63) 645CiBMW 8 Series (E31) 850Ci 5.4PowerTorque
  • BMW 6 Series (E63) 645Ci: Power / Torque
  • BMW 8 Series (E31) 850Ci 5.4: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
BMW6 Series (E63)645Ci6,100 rpm3,600 rpm6,350 rpm
BMW8 Series (E31)850Ci 5.45,000 rpm3,900 rpm5,250 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW6 Series (E63)645CiBMW8 Series (E31)850Ci 5.4
Acceleration checkpoints
0-60 mph
0-97 km/h
5.5 s
6.0 s
0-100 km/h
0-62 mph
5.8 s
6.3 s
0-200 km/h
0-124 mph
20.3 s
22.6 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Likely limited
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Likely limited
Drag race simulation
60 ft
18 m
2.3 s
2.4 s
330 ft
101 m
6.1 s
6.3 s
1/8 mile
201 m
9.1 s
9.4 s
1000 ft
305 m
11.7 s
12.1 s
1/4 mile
402 m
13.9 s
14.3 s
Trap speed
1/4 mile
402 m
169 km/h
105 mph
163 km/h
101 mph

Power comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
333 hp
248 kW
BMW8 Series (E31)850Ci 5.4
326 hp
243 kW

BMW 6 Series (E63) 645Ci has 7 hp more than BMW 8 Series (E31) 850Ci 5.4.

The biggest power difference is between BMW 8 Series (E31) 850Ci 5.4 and BMW 6 Series (E63) 645Ci: 7 hp (5 kW).

Torque comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
450 Nm
332 lb-ft
BMW8 Series (E31)850Ci 5.4
490 Nm
361 lb-ft

Curb weight comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
1,695 kg
3,737 lb
BMW8 Series (E31)850Ci 5.4
1,880 kg
4,145 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 (E63)645Ci
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
BMW8 Series (E31)850Ci 5.4
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph

0-100 km/h comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci5.8 s
BMW8 Series (E31)850Ci 5.46.3 s

The biggest 0-100 km/h difference is between BMW 6 Series (E63) 645Ci and BMW 8 Series (E31) 850Ci 5.4: 0.5 s.

Power-to-weight comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
196 hp/t
147 kW/t
5.1 kg/hp
BMW8 Series (E31)850Ci 5.4
173 hp/t
129 kW/t
5.8 kg/hp

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
BMW6 Series (E63)645Ci
333 hp
248 kW
5.8 s
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
BMW8 Series (E31)850Ci 5.4
326 hp
243 kW
6.3 s
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 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 (E63)645Ci
Power
333 hp
248 kW
0-100 km/h5.8 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
4 seats
Trunk
450 L
15.9 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
BMW8 Series (E31)850Ci 5.4
Power
326 hp
243 kW
0-100 km/h6.3 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
4 seats
Trunk
320 L
11.3 cu ft
Length
4,780 mm
188.2 in
Height
1,340 mm
52.8 in

Detailed score breakdown

Detailed score breakdown
VehicleBMW6 Series (E63)645CiBMW8 Series (E31)850Ci 5.4
Power
333 hp
248 kW
326 hp
243 kW
Torque
450 Nm
332 lb-ft
490 Nm
361 lb-ft
Acceleration
5.8 s
6.3 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Lightness
1,695 kg
3,737 lb
1,880 kg
4,145 lb
Fuel consumption
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
-
Practicality
Doors/seats
2 doors
4 seats
Trunk
450 L
15.9 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
Doors/seats
2 doors
4 seats
Trunk
320 L
11.3 cu ft
Length
4,780 mm
188.2 in
Height
1,340 mm
52.8 in
Range score
642 km
399 mi
-
CO2 score
264 g/km
-
Trunk score
450 L
15.9 cu ft
320 L
11.3 cu ft
Power-to-weight score
196 hp/t
147 kW/t
5.1 kg/hp
173 hp/t
129 kW/t
5.8 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 6 Series (E63) 645Ci
Consumption10.9 L/100 km21.6 mpg US25.9 mpg UK
Cost / 100 km19.08 LC100 km
Cost / 100 mi30.70 LC100 mi
Annual fuel used1,635 L432 US gal360 UK gal
Annual fuel cost2,861 LC/year

Head-to-head comparisons

BMW 6 Series (E63) 645Ci

  • Has 7 hp more
  • Is 185 kg lighter
  • Is 0.5 s quicker from 0-100 km/h
  • Has 23 hp/t better power-to-weight
  • Has 130 L more trunk volume

Pros

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

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW 6 Series (E63) 645Ci
BMW 8 Series (E31) 850Ci 5.4
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2 vehicles selected

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