Car comparison

Alfa Romeo 8C Spider 4.7 V8vsMercedes-Benz SLK (R171) · Facelift 2008 AMG SLK 55 V8

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

New comparison

Alfa Romeo 8C Spider

4.7 V8

450 hp4691 ccGasolineRWDManualNaturally aspiratedRoadster2008-2010
VS

Mercedes-Benz SLK (R171) · Facelift 2008

AMG SLK 55 V8

360 hp5439 ccGasolineRWDAutomaticNaturally aspiratedRoadster2008-2011

Comparison overview

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

Best choices

Alfa Romeo 8C Spider 4.7 V8

  • Quickest 0-100 km/h
    4.4 s
  • Fastest top speed
    300 km/h
    186 mph Unrestricted
    290 km/h
    180 mph Restricted
  • Most powerful
    450 hp
    336 kW
  • Best power-to-weight
    269 hp/t
    200 kW/t
    3.7 kg/hp
  • Best overall score
    65/100
  • Best performance score
    80/100
  • Best practicality score
    32/100

Specification comparison

Specification comparison
ModelAlfa Romeo8C Spider4.7 V8Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
Power
450hp336kW
360hp268kW
Torque
480Nm354lb-ft
510Nm376lb-ft
Curb weight
1,675kg3,693lb
1,500kg3,307lb
Gross weight
1,855kg4,090lb
1,850kg4,079lb
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Calculated
Unrestricted
270 km/h168 mph
Restricted
250 km/h155 mph
Calculated
To 99% top speed
67.0s99% target: 297 km/h / 185 mph
Calculated
61.9s99% target: 267 km/h / 166 mph
Calculated
0-100 km/h
4.4s
4.9s
0-200 km/h
13.5s
Calculated
16.0s
Calculated
0-60 mph
4.2s
Calculated
4.7s
Calculated
Fuel consumption
15.8L/100 km14.9mpg US17.9mpg UK
12L/100 km19.6mpg US23.5mpg UK
Fuel consumption city-
17.7L/100 km13.3mpg US16.0mpg UK
Fuel consumption highway-
8.8L/100 km26.7mpg US32.1mpg UK
Quarter mile
12.3s
Calculated
12.9s
Calculated
Power-to-weight
269hp/t200kW/t122hp/1000 lb
Calculated
240hp/t179kW/t109hp/1000 lb
Calculated
Torque-to-weight
287Nm/t192lb-ft/ton
Calculated
340Nm/t227lb-ft/ton
Calculated
Estimated range
557km346mi
Calculated
583km362mi
Calculated
Displacement
4,691cc286cu in
5,439cc332cu in
Length
4,381mm172in
4,103mm162in
Width
1,892mm74in
1,788mm70in
Height
1,366mm54in
1,271mm50in
Wheelbase
2,645mm104in
2,430mm96in
Front track
1,590mm63in
1,524mm60in
Rear track
1,589mm63in
1,549mm61in
Ground clearance
140mm6in
-
Trunk volume-
208L
Doors
2
2
Seats
2
2
Fuel tank
88L
70L
CO2 emissions
377g/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.

Alfa Romeo 8C Spider 4.7 V8Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8PowerTorque
  • Alfa Romeo 8C Spider 4.7 V8: Power / Torque
  • Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
Alfa Romeo8C Spider4.7 V87,000 rpm4,750 rpm7,500 rpm
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V85,750 rpm4,000 rpm6,000 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricAlfa Romeo8C Spider4.7 V8Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
Acceleration checkpoints
0-60 mph
0-97 km/h
4.2 s
4.7 s
0-100 km/h
0-62 mph
4.4 s
4.9 s
0-200 km/h
0-124 mph
13.5 s
16.0 s
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Likely limited
Unrestricted
270 km/h168 mph
Restricted
250 km/h155 mph
Limited
Drag race simulation
60 ft
18 m
2.1 s
2.2 s
330 ft
101 m
5.5 s
5.7 s
1/8 mile
201 m
8.1 s
8.5 s
1000 ft
305 m
10.4 s
10.9 s
1/4 mile
402 m
12.3 s
12.9 s
Trap speed
1/4 mile
402 m
192 km/h
119 mph
181 km/h
113 mph

Power comparison

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

Chart data table
VehicleValue
Alfa Romeo8C Spider4.7 V8
450 hp
336 kW
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
360 hp
268 kW

Alfa Romeo 8C Spider 4.7 V8 has 90 hp more than Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8.

The biggest power difference is between Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8 and Alfa Romeo 8C Spider 4.7 V8: 90 hp (67 kW).

Torque comparison

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

Chart data table
VehicleValue
Alfa Romeo8C Spider4.7 V8
480 Nm
354 lb-ft
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
510 Nm
376 lb-ft

Curb weight comparison

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

Chart data table
VehicleValue
Alfa Romeo8C Spider4.7 V8
1,675 kg
3,693 lb
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
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
Alfa Romeo8C Spider4.7 V8
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
Unrestricted
270 km/h168 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
Alfa Romeo8C Spider4.7 V84.4 s
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V84.9 s

The biggest 0-100 km/h difference is between Alfa Romeo 8C Spider 4.7 V8 and Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8: 0.5 s.

Fuel consumption comparison

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

Chart data table
VehicleValue
Alfa Romeo8C Spider4.7 V8
15.8 L/100 km
14.9 mpg US
17.9 mpg UK
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
12.0 L/100 km
19.6 mpg US
23.5 mpg UK

The biggest fuel consumption difference is between Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8 and Alfa Romeo 8C Spider 4.7 V8: 3.8 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
Alfa Romeo8C Spider4.7 V8
269 hp/t
200 kW/t
3.7 kg/hp
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
240 hp/t
179 kW/t
4.2 kg/hp

Estimated range comparison

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

Chart data table
VehicleValue
Alfa Romeo8C Spider4.7 V8
557 km
346 mi
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
583 km
362 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
Alfa Romeo8C Spider4.7 V8
450 hp
336 kW
4.4 s
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
360 hp
268 kW
4.9 s
Unrestricted
270 km/h168 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
Alfa Romeo8C Spider4.7 V8
Power
450 hp
336 kW
0-100 km/h4.4 s
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Doors/seats
2 doors
2 seats
Trunk-
Length
4,381 mm
172.5 in
Height
1,366 mm
53.8 in
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
Power
360 hp
268 kW
0-100 km/h4.9 s
Top speed
Unrestricted
270 km/h168 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
2 seats
Trunk
208 L
7.3 cu ft
Length
4,103 mm
161.5 in
Height
1,271 mm
50.0 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
Alfa Romeo8C Spider4.7 V8
Power
450 hp
336 kW
0-100 km/h4.4 s
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
15.8 L/100 km
14.9 mpg US
17.9 mpg UK
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
Power
360 hp
268 kW
0-100 km/h4.9 s
Top speed
Unrestricted
270 km/h168 mph
Restricted
250 km/h155 mph
12.0 L/100 km
19.6 mpg US
23.5 mpg UK

Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8 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
Alfa Romeo8C Spider4.7 V8
15.8 L/100 km
14.9 mpg US
17.9 mpg UK
4.4 s
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
12.0 L/100 km
19.6 mpg US
23.5 mpg UK
4.9 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
Alfa Romeo8C Spider4.7 V8
269 hp/t
200 kW/t
3.7 kg/hp
15.8 L/100 km
14.9 mpg US
17.9 mpg UK
Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
240 hp/t
179 kW/t
4.2 kg/hp
12.0 L/100 km
19.6 mpg US
23.5 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleAlfa Romeo8C Spider4.7 V8Mercedes-BenzSLK (R171)Facelift 2008AMG SLK 55 V8
Power
450 hp
336 kW
360 hp
268 kW
Torque
480 Nm
354 lb-ft
510 Nm
376 lb-ft
Acceleration
4.4 s
4.9 s
Top speed
Unrestricted
300 km/h186 mph
Restricted
290 km/h180 mph
Unrestricted
270 km/h168 mph
Restricted
250 km/h155 mph
Lightness
1,675 kg
3,693 lb
1,500 kg
3,307 lb
Fuel consumption
15.8 L/100 km
14.9 mpg US
17.9 mpg UK
12.0 L/100 km
19.6 mpg US
23.5 mpg UK
Practicality
Doors/seats
2 doors
2 seats
Trunk-
Length
4,381 mm
172.5 in
Height
1,366 mm
53.8 in
Doors/seats
2 doors
2 seats
Trunk
208 L
7.3 cu ft
Length
4,103 mm
161.5 in
Height
1,271 mm
50.0 in
Range score
557 km
346 mi
583 km
362 mi
CO2 score
377 g/km
-
Trunk score
-
208 L
7.3 cu ft
Power-to-weight score
269 hp/t
200 kW/t
3.7 kg/hp
240 hp/t
179 kW/t
4.2 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
VehicleAlfa Romeo 8C Spider 4.7 V8Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8
Consumption15.8 L/100 km14.9 mpg US17.9 mpg UK12 L/100 km19.6 mpg US23.5 mpg UK
Cost / 100 km27.65 LC100 km21.00 LC100 km
Cost / 100 mi44.50 LC100 mi33.80 LC100 mi
Annual fuel used2,370 L626 US gal521 UK gal1,800 L476 US gal396 UK gal
Annual fuel cost4,148 LC/year3,150 LC/year

Head-to-head comparisons

Alfa Romeo 8C Spider 4.7 V8

  • Has 90 hp more
  • Is 0.5 s quicker from 0-100 km/h
  • Has 30 km/h (19 mph) higher top speed
  • Has 29 hp/t better power-to-weight

Pros

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

Cons

  • Highest combined fuel consumption
  • Heaviest

Mercedes-Benz SLK (R171) Facelift 2008 AMG SLK 55 V8

  • Has 30 Nm more
  • Is 175 kg lighter
  • Uses 3.8 L/100 km less fuel
  • Has 26 km (16 mi) more estimated range

Pros

  • Highest torque
  • Lightest
  • Lowest combined fuel consumption
  • Best estimated range

Cons

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

Choose cars to compare

Brand
Model
Generation
Engine or modification
Alfa Romeo 8C Spider 4.7 V8
Mercedes-Benz SLK (R171) AMG SLK 55 V8
Compare selected cars
2 vehicles selected

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