Car comparison

Porsche Boxster (981) Spyder 3.8vsBMW Z4 (G29) M40i

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

New comparison

Porsche Boxster (981)

Spyder 3.8

375 hp3800 ccGasolineRWDManualNaturally aspiratedRoadster2015-2016
VS

BMW Z4 (G29)

M40i

340 hp2998 ccGasolineAWDAutomaticTurbochargedRoadster2018-2022

Comparison overview

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

Best choices

BMW Z4 (G29) M40i

  • Highest torque
    500 Nm
    369 lb-ft
  • Lowest combined fuel consumption
    7.4 L/100 km
    31.8 mpg US
    38.2 mpg UK
  • Lowest city consumption
    9.2 L/100 km
    25.6 mpg US
    30.7 mpg UK
  • Lowest highway consumption
    6.3 L/100 km
    37.3 mpg US
    44.8 mpg UK
  • Best estimated range
    703 km
    437 mi
  • Largest trunk
    281 L
  • Best economy score
    87/100
  • Best practicality score
    32/100

Porsche Boxster (981) Spyder 3.8

  • Quickest 0-100 km/h
    4.5 s
  • Fastest top speed
    300 km/h
    186 mph Unrestricted
    290 km/h
    180 mph Restricted
  • Most powerful
    375 hp
    280 kW
  • Lightest
    1,315 kg
    2,899 lb
  • Best power-to-weight
    285 hp/t
    213 kW/t
    3.5 kg/hp
  • Best overall score
    62/100
  • Best performance score
    77/100

Specification comparison

Specification comparison
ModelPorscheBoxster (981)Spyder 3.8BMWZ4 (G29)M40i
Power
375hp280kW
340hp254kW
Torque
420Nm310lb-ft
500Nm369lb-ft
Curb weight
1,315kg2,899lb
1,535kg3,384lb
Gross weight
1,650kg3,638lb
1,860kg4,101lb
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Calculated
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Calculated
To 99% top speed
61.8s99% target: 297 km/h / 185 mph
Calculated
57.6s99% target: 262 km/h / 163 mph
Calculated
0-100 km/h
4.5s
4.5s
0-200 km/h
13.2s
Calculated
15.2s
Calculated
0-60 mph
4.3s
Calculated
4.3s
Calculated
Fuel consumption
9.9L/100 km23.8mpg US28.5mpg UK
7.4L/100 km31.8mpg US38.2mpg UK
Fuel consumption city
14.2L/100 km16.6mpg US19.9mpg UK
9.2L/100 km25.6mpg US30.7mpg UK
Fuel consumption highway
7.5L/100 km31.4mpg US37.7mpg UK
6.3L/100 km37.3mpg US44.8mpg UK
Quarter mile
12.4s
Calculated
12.6s
Calculated
Power-to-weight
285hp/t213kW/t129hp/1000 lb
Calculated
221hp/t165kW/t100hp/1000 lb
Calculated
Torque-to-weight
319Nm/t214lb-ft/ton
Calculated
326Nm/t218lb-ft/ton
Calculated
Estimated range
545km339mi
Calculated
703km437mi
Calculated
Displacement
3,800cc232cu in
2,998cc183cu in
Length
4,414mm174in
4,324mm170in
Width
1,801mm71in
1,864mm73in
Height
1,262mm50in
1,304mm51in
Wheelbase
2,475mm97in
2,470mm97in
Front track
1,526mm60in
1,594mm63in
Rear track
1,540mm61in
1,589mm63in
Ground clearance
106mm4in
114mm4in
Trunk volume
280L
281L
Doors
2
2
Seats
2
2
Fuel tank
54L
52L
CO2 emissions-
168g/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.

Porsche Boxster (981) Spyder 3.8BMW Z4 (G29) M40iPowerTorque
  • Porsche Boxster (981) Spyder 3.8: Power / Torque
  • BMW Z4 (G29) M40i: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
PorscheBoxster (981)Spyder 3.86,700 rpm4,750-6,000 rpm6,950 rpm
BMWZ4 (G29)M40i5,000-6,500 rpm1,600-4,500 rpm6,750 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricPorscheBoxster (981)Spyder 3.8BMWZ4 (G29)M40i
Acceleration checkpoints
0-60 mph
0-97 km/h
4.3 s
4.3 s
0-100 km/h
0-62 mph
4.5 s
4.5 s
0-200 km/h
0-124 mph
13.2 s
15.2 s
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Likely limited
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Likely limited
Drag race simulation
60 ft
18 m
2.2 s
2.1 s
330 ft
101 m
5.5 s
5.5 s
1/8 mile
201 m
8.2 s
8.2 s
1000 ft
305 m
10.5 s
10.6 s
1/4 mile
402 m
12.4 s
12.6 s
Trap speed
1/4 mile
402 m
194 km/h
120 mph
184 km/h
114 mph

Power comparison

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

Chart data table
VehicleValue
PorscheBoxster (981)Spyder 3.8
375 hp
280 kW
BMWZ4 (G29)M40i
340 hp
254 kW

Porsche Boxster (981) Spyder 3.8 has 35 hp more than BMW Z4 (G29) M40i.

The biggest power difference is between BMW Z4 (G29) M40i and Porsche Boxster (981) Spyder 3.8: 35 hp (26 kW).

Torque comparison

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

Chart data table
VehicleValue
PorscheBoxster (981)Spyder 3.8
420 Nm
310 lb-ft
BMWZ4 (G29)M40i
500 Nm
369 lb-ft

Curb weight comparison

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

Chart data table
VehicleValue
PorscheBoxster (981)Spyder 3.8
1,315 kg
2,899 lb
BMWZ4 (G29)M40i
1,535 kg
3,384 lb

Top speed without limiter comparison

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

Chart data table
VehicleValue
PorscheBoxster (981)Spyder 3.8
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
BMWZ4 (G29)M40i
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
PorscheBoxster (981)Spyder 3.84.5 s
BMWZ4 (G29)M40i4.5 s

Fuel consumption comparison

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

Chart data table
VehicleValue
PorscheBoxster (981)Spyder 3.8
9.9 L/100 km
23.8 mpg US
28.5 mpg UK
BMWZ4 (G29)M40i
7.4 L/100 km
31.8 mpg US
38.2 mpg UK

The biggest fuel consumption difference is between BMW Z4 (G29) M40i and Porsche Boxster (981) Spyder 3.8: 2.5 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
PorscheBoxster (981)Spyder 3.8
285 hp/t
213 kW/t
3.5 kg/hp
BMWZ4 (G29)M40i
221 hp/t
165 kW/t
4.5 kg/hp

Estimated range comparison

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

Chart data table
VehicleValue
PorscheBoxster (981)Spyder 3.8
545 km
339 mi
BMWZ4 (G29)M40i
703 km
437 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
PorscheBoxster (981)Spyder 3.8
375 hp
280 kW
4.5 s
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
BMWZ4 (G29)M40i
340 hp
254 kW
4.5 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
PorscheBoxster (981)Spyder 3.8
Power
375 hp
280 kW
0-100 km/h4.5 s
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Doors/seats
2 doors
2 seats
Trunk
280 L
9.9 cu ft
Length
4,414 mm
173.8 in
Height
1,262 mm
49.7 in
BMWZ4 (G29)M40i
Power
340 hp
254 kW
0-100 km/h4.5 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
2 seats
Trunk
281 L
9.9 cu ft
Length
4,324 mm
170.2 in
Height
1,304 mm
51.3 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
PorscheBoxster (981)Spyder 3.8
Power
375 hp
280 kW
0-100 km/h4.5 s
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
9.9 L/100 km
23.8 mpg US
28.5 mpg UK
BMWZ4 (G29)M40i
Power
340 hp
254 kW
0-100 km/h4.5 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
7.4 L/100 km
31.8 mpg US
38.2 mpg UK

BMW Z4 (G29) M40i 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
PorscheBoxster (981)Spyder 3.8
9.9 L/100 km
23.8 mpg US
28.5 mpg UK
4.5 s
BMWZ4 (G29)M40i
7.4 L/100 km
31.8 mpg US
38.2 mpg UK
4.5 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
PorscheBoxster (981)Spyder 3.8
285 hp/t
213 kW/t
3.5 kg/hp
9.9 L/100 km
23.8 mpg US
28.5 mpg UK
BMWZ4 (G29)M40i
221 hp/t
165 kW/t
4.5 kg/hp
7.4 L/100 km
31.8 mpg US
38.2 mpg UK

Detailed score breakdown

Detailed score breakdown
VehiclePorscheBoxster (981)Spyder 3.8BMWZ4 (G29)M40i
Power
375 hp
280 kW
340 hp
254 kW
Torque
420 Nm
310 lb-ft
500 Nm
369 lb-ft
Acceleration
4.5 s
4.5 s
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Lightness
1,315 kg
2,899 lb
1,535 kg
3,384 lb
Fuel consumption
9.9 L/100 km
23.8 mpg US
28.5 mpg UK
7.4 L/100 km
31.8 mpg US
38.2 mpg UK
Practicality
Doors/seats
2 doors
2 seats
Trunk
280 L
9.9 cu ft
Length
4,414 mm
173.8 in
Height
1,262 mm
49.7 in
Doors/seats
2 doors
2 seats
Trunk
281 L
9.9 cu ft
Length
4,324 mm
170.2 in
Height
1,304 mm
51.3 in
Range score
545 km
339 mi
703 km
437 mi
CO2 score
-
168 g/km
Trunk score
280 L
9.9 cu ft
281 L
9.9 cu ft
Power-to-weight score
285 hp/t
213 kW/t
3.5 kg/hp
221 hp/t
165 kW/t
4.5 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
VehiclePorsche Boxster (981) Spyder 3.8BMW Z4 (G29) M40i
Consumption9.9 L/100 km23.8 mpg US28.5 mpg UK7.4 L/100 km31.8 mpg US38.2 mpg UK
Cost / 100 km17.33 LC100 km12.95 LC100 km
Cost / 100 mi27.88 LC100 mi20.84 LC100 mi
Annual fuel used1,485 L392 US gal327 UK gal1,110 L293 US gal244 UK gal
Annual fuel cost2,599 LC/year1,943 LC/year

Head-to-head comparisons

Porsche Boxster (981) Spyder 3.8

  • Has 35 hp more
  • Is 220 kg lighter
  • Has 35 km/h (22 mph) higher top speed
  • Has 64 hp/t better power-to-weight

Pros

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

Cons

  • Highest combined fuel consumption
  • Smallest trunk

BMW Z4 (G29) M40i

  • Has 80 Nm more
  • Uses 2.5 L/100 km less fuel
  • Has 157 km (98 mi) more estimated range
  • Has 1 L more trunk volume

Pros

  • Highest torque
  • Lowest combined fuel consumption
  • Best estimated range
  • Largest trunk

Cons

  • Lowest power
  • Heaviest
  • Lowest top speed

Choose cars to compare

Brand
Model
Generation
Engine or modification
Porsche Boxster (981) Spyder 3.8
BMW Z4 (G29) M40i
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