# Power-to-weight ratio: Wikis

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# Encyclopedia

Power-to-weight ratio (or specific power or power-to-mass ratio) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power sources. It is also used a measure of performance of a vehicle as a whole, with the engine's power output being divided by the weight (or mass) of the vehicle, to give a metric that is independent of the vehicle's size.

The inverse of power-to-weight, weight-to-power ratio (power loading) is a calculation commonly applied to aircraft, cars, and vehicles in general, to enable the comparison of one vehicle performance to another. Weight-to-power ratio is a measurement of the acceleration capability (potential) of any land vehicle or climb performance of any aircraft or space vehicle.

## Power to weight (specific power)

The power-to-weight ratio (Specific Power) formula for an engine (power plant) is the power generated by the engine divided by weight of the engine as follows:

$\begin{matrix} \mbox{P-to-W}&= P/W \ \end{matrix}$

A typical turbocharged V-8 diesel engine might have an engine power of 330 horsepower (250 kW) and a weight of 835 pounds (379 kg)[1], giving it a power-to-weight ratio of 0.65 kW/kg (0.40 hp/lb).

Examples of high power-to-weight ratios can often be found in turbines. This is because of their ability to operate at very high speeds. For example, the Space Shuttle's main engines use turbopumps (machines consisting of a pump driven by a turbine engine) to feed the propellants (liquid oxygen and liquid hydrogen) into the engine's combustion chamber. The original liquid hydrogen turbopump is similar in size to an automobile engine (weighing approximately 775 pounds (352 kg)) and produces 72,000 hp (53.6 MW)[2] for a power-to-weight ratio of 153 kW/kg (93 hp/lb).

### Physical Interpretation

In classical mechanics, instantaneous power is the limiting value of the average rate of change of work done per unit time as the time interval Δt approaches zero.

$P = \lim _{\Delta t\rightarrow 0} \tfrac{\Delta W(t)}{\Delta t} = \lim _{\Delta t\rightarrow 0} P_\mathrm{avg}\,$

If the work to be done is rectilinear motion of a body with constant mass $m\;$, whose center of mass is to be accelerated along a straight line to a speed $|\mathbf{v}(t)|\;$ and angle $\phi\;$ with respect to the centre and radial of a gravitational field by an onboard powerplant, then the associated kinetic energy to be delivered to the body is equal to

$E_K =\tfrac{1}{2} m|\mathbf{v}(t)|^2$

where:

$m\;$ is mass of the body
$|\mathbf{v}(t)|\;$ is speed of the center of mass of the body, changing with time.

The instantaneous mechanical pushing/pulling power delivered to the body from the powerplant is then

$P_K =\tfrac{1}{2} m 2|\mathbf{v}(t)| \lim _{\Delta t\rightarrow 0} \tfrac{\Delta |\mathbf{v}(t)|}{\Delta t} = m \mathbf{a}(t) \cdot \mathbf{v}(t) = \mathbf{F}(t) \cdot \mathbf{v}(t) = \mathbf{\tau}(t) \cdot \mathbf{\omega}(t)$

where:

$\mathbf{a}(t)\;$ is acceleration of the center of mass of the body, changing with time.
$\mathbf{F}(t)\;$ is linear force applied upon the center of mass of the body, changing with time.
$\mathbf{v}(t)\;$ is velocity of the center of mass of the body, changing with time.
$\mathbf{\tau}(t)\;$ is torque applied upon the center of mass of the body, changing with time.
$\mathbf{\omega}(t)\;$ is angular velocity of the center of mass of the body, changing with time.

Along an obstacle free positive inclined straight road steering an automobile straight ahead, positive linear acceleration will change the speed but not the direction of the vehicle.

The weight of the body is the force applied to the body to support it at rest in a uniform gravitational field, g. Using Newton's Second Law of Motion, then

$\mathbf{F_W} = -m \mathbf{g} \;$

where:

$m\;$ is mass of the body
$\mathbf{g}\;$ is gravitational field (acceleration) vector

For large changes in altitude or with a body of mass significant when compared with the gravitational field source mass, then the gravitational field may no longer be considered uniform and therefore g also changes with time.

The torque from the powerplant is accelerating the body to a desired velocity of motion whilst lifting the weight of the body, overcoming friction through the powerplant and upon the surface of the body (e.g. rolling resistance and skin friction), and overcoming other drag from the motion of the body through fluids (e.g. air, water). The degree in which the deliverable torque associated with the body overcomes the force of gravity upon the body and yields a net positive linear climbing acceleration, or mechanical advantage, is then

$\mbox{MA}=\frac{m \mathbf{a}(t) - F_F - F_D}{-m \mathbf{g}} = \frac{|\mathbf{a}(t)| - \tfrac{1}{m}F_F(m,|\mathbf{v}(t)|) - \tfrac{1}{m}F_D(|\mathbf{v}(t)|)}{|\mathbf{g}|}\;$

where:

$m\;$ is mass of the body
$|\mathbf{v}(t)|\;$ is linear speed of the center of mass of the body, changing with time.
$\mathbf{a}(t)\;$ is powerplant acceleration of the center of mass of the body, changing with time.
$\mathbf{g}\;$ is gravitational acceleration of the center of mass of the body.
$F_F\;$ is force of friction within powerplant and upon surface of the body.
$F_D\;$ is force of drag.

If the friction and drag loses are negligible, then the powerplant will convert essentially all its power to either delivering kinetic energy to the body or lifting the weight of the body. To meet this ideal, techniques include low rolling resistance tyres, sufficient tyre inflation, obstacle free path, straight asphalt road, low automotive aerodynamic drag area, well lubricated powertrain and a low loss mechanical transmission to run the engine at a speed that corresponds with the engine peak output power. The mechanical advantage is then simply

$\mbox{MA} = \frac{|\mathbf{a}(t)|}{|\mathbf{g}|}\;$

Power is only delivered if the powerplant is in motion, and is transmitted to cause the body to be in motion. It is typically assumed here that mechanical transmission allows the powerplant to operate at peak output power. This assumption allows engine tuning to trade power band width and engine mass for transmission complexity and mass. Electric motors do not suffer from this tradeoff. The power advantage or power-to-weight ratio is then

$\mbox{P-to-W} = \frac{|\mathbf{a}(t)||\mathbf{v}(t)|}{|\mathbf{g}|}\;$

where:

$|\mathbf{v}(t)|\;$ is linear speed of the center of mass of the body.

Power-to-weight ratio is relative to a uniform gravitational field. Normalising to any arbitrary gravitational field yields the specific power or power-to-mass ratio which is then

$\mbox{P-to-M} = |\mathbf{a}(t)||\mathbf{v}(t)| = \frac{|\mathbf{\tau}(t)||\mathbf{\omega}(t)|}{m}\;$

The power-to-weight ratio is typically calculated from power and mass, although mass is usually measured as weight on a calibrated weighing scale. Values are then expressed in units power per unit force exerted on unit mass in standard gravity. Use of kg (kilogram) and lb (pound) rather than kgf (kilogram-force), SI unit N (Newton) or lbf (pound-force) is common. The value thus expressed is the power-to-mass ratio and not the power-to-weight ratio.

The actual useful power of any traction engine can be calculated using a dynamometer to measure torque and rotational speed. For jet engines there is often a cruise speed and power can be usefully calculated there, for rockets there is typically no cruise speed, so it is less meaningful.

## Examples

### Engines

#### Heat Engines and Heat Pumps

Thermal energy is made up from molecular kinetic energy and latent phase energy. Heat engines are able to convert thermal energy in the form of a temperature gradient between a hot source and a cold sink into other desirable mechanical work. Heat pumps take mechanical work to regenerate thermal energy in a temperature gradient.

Heat Engine/Heat Pump type Peak Power Output Power-to-weight ratio Example Use
Wärtsilä RTA96-C 14-cylinder two-stroke Turbo Diesel engine[3] 80,080 kW 108,920 hp 0.03 kW/kg 0.02 hp/lb Emma Mærsk container ship
Suzuki 538cc V2 4-stroke gas (petrol) outboard Otto engine[4] 19 kW 25 hp 0.27 kW/kg 0.16 hp/lb Runabout boats
GM 6.6L Duramax LMM (LYE option) V8 Turbo Diesel engine[1] 246 kW 330 hp 0.65 kW/kg 0.40 hp/lb Chevrolet Kodiak, GMC Topkick
Junkers Jumo 205A opposed-piston two-stroke Diesel engine[5] 647 kW 867 hp 1.1 kW/kg 0.66 hp/lb Ju 86C-1 airliner, B&V Ha 139 floatplane
GE LM2500+ marine turboshaft Brayton gas turbine[6] 30,200 kW 40,500 hp 1.31 kW/kg 0.80 hp/lb GTS Millennium cruiseship,QM2 ocean liner
Mazda 13B-MSP Renesis 1.3L Wankel engine[7] 184 kW 247 hp 1.5 kW/kg 0.92 hp/lb Mazda RX-8
PW R-4360 71.5L 28-cylinder supercharged Radial engine 3,210 kW 4,300 hp 1.83 kW/kg 1.11 hp/lb B-50 Superfortress, Convair B-36
C-97 Stratofreighter, C-119 Flying Boxcar
Hughes H-4 Hercules "Spruce Goose"
Pattakon OPRE two stroke Diesel engine[8] 50 kW 70 hp 2.3 kW/kg 1.4 hp/lb
O.S. Engines 49-PI Type II 4.97cc UAV Wankel engine[9] 0.934 kW 1.252 hp 2.8 kW/kg 1.7 hp/lb Model aircraft, Radio-controlled aircraft
GE LM6000 marine turboshaft Brayton gas turbine[10][11] 44,700 kW 59,900 hp 5.67 kW/kg 3.38 hp/lb Peaking power plant
GE CF6-80C2 Brayton high-bypass turbofan jet engine[11] Boeing 747,767,Airbus A300
BMW V10 3L P84/5 2005 gas (petrol) Otto engine[12] 690 kW 925 hp 7.5 kW/kg 4.6 hp/lb Williams FW27 car, Formula One auto racing
GE90-115B Brayton turbofan jet engine[13][14] 83,164 kW 111,526 hp 10.0 kW/kg 6.10 hp/lb Boeing 777
PWR RS-24 (SSME) Block II H2 Brayton turbopump[15][16] 63,384 kW 85,000 hp 138 kW/kg 84 hp/lb Space Shuttle (STS-110 and later)
PWR RS-24 (SSME) Block I H2 Brayton turbopump[2] 53,690 kW 72,000 hp 153 kW/kg 93 hp/lb Space Shuttle

#### Electric Motors/Electromotive Generators

An electric motor uses electrical energy to provide mechanical work, usually through the interaction of a magnetic field and current-carrying conductors. By the interaction of mechanical work on an electrical conductor in a magnetic field, electrical energy can be generated.

Electric Motor type Weight Peak Power Output Power-to-weight ratio Example Use
Toyota Brushless AC NdFeB PM motor[17] 183 kg 403 lb 50 kW 67 hp 0.27 kW/kg 0.17 hp/lb Toyota Prius 2004
Panasonic MSMA202S1G AC servo motor[18] 6.5 kg 14.3 lb 2 kW 2.7 hp 0.31 kW/kg 0.19 hp/lb Conveyor belts, Robotics
Toshiba 660 MVA water cooled 23kV AC turbo generator 1,342 t 2,959,000 lb 660 MW 885,000 hp 0.49 kW/kg 0.30 hp/lb Bayswater, Eraring Coal Power stations
Canopy Tech. Cypress 32MW 15kV AC PM generator[19] 33,557 kg 73,981 lb 32 MW 42,913 hp 0.95 kW/kg 0.58 hp/lb Electric Power stations
Himax HC6332-250 Brushless DC motor[20] 0.45 kg 0.99 lb 1.7 kW 2.28 hp 3.78 kW/kg 2.30 hp/lb Radio controlled cars
Hi-Pa Drive HPD40 Brushless DC wheel hub motor[21] 25 kg 55.1 lb 120 kW 161 hp 4.8 kW/kg 2.92 hp/lb Mini QED HEV, Ford F150 HEV

#### Fluid Engines and Fluid Pumps

Fluids (liquid and gas) can be used to transmit and/or store energy using pressure and other fluid properties. Hydraulic (liquid) and pneumatic (gas) engines convert fluid pressure into other desirable mechanical or electrical work. Fluid pumps convert mechanical or electrical work into movement or pressure changes of a fluid, or storage in a pressure vessel.

Fluid Powerplant type Dry Weight Peak Power Output Power-to-weight ratio
PlatypusPower Q2/200 hydroelectric turbine[22] 43 kg 95 lb 2 kW 2.7 hp 0.047 kW/kg 0.029 hp/lb
PlatypusPower PP20/200 hydroelectric turbine[22] 330 kg 728 lb 20 kW 27 hp 0.060 kW/kg 0.037 hp/lb
Atlas Copco LZL 35 pneumatic motor[23] 20 kg 44.1 lb 5.2 kW 7 hp 0.26 kW/kg 0.16 hp/lb
Bosch 0 607 954 307 pneumatic motor[24] 0.32 kg 0.71 lb 0.1 kW 0.13 hp 0.31 kW/kg 0.19 hp/lb
Bosch 0 607 957 307 pneumatic motor[24] 1.7 kg 3.7 lb 0.74 kW 0.99 hp 0.44 kW/kg 0.26 hp/lb
SAI GM7 radial piston hydraulic motor[25] 300 kg 661 lb 250 kW 335 hp 0.83 kW/kg 0.50 hp/lb
SAI GM3 radial piston hydraulic motor[26] 15 kg 33 lb 15 kW 20 hp 1 kW/kg 0.61 hp/lb

#### Thermoelectric Generators and Electrothermal Actuators

A variety of effects can be harnessed to produce thermoelectricity, thermionic emission, pyroelectricity and piezoelectricity. Electrical resistance and ferromagnetism of materials can be harnessed to generate thermoacoustic energy from an electric current.

Thermoelectric Powerplant type Dry Weight Peak Power Output Power-to-weight ratio Example Use
Teledyne 238Pu GPHS-RTG 1980[27][28] 56 kg 123 lb 285 We 0.39 hp 5.09 W/kg 0.003 hp/lb Galileo probe, New Horizons probe
Boeing 238Pu MMRTG MSL [28] 44.1 kg 97.2 lb 123 We 0.16 hp 2.79 W/kg 0.002 hp/lb Mars Science Laboratory

### Electrochemical (Galvanic) cell systems

#### (Closed Cell) Batteries

All electrochemical cell batteries deliver a changing voltage as their chemistry changes from "charged" to "discharged". A nominal output voltage and a cutoff voltage are typically specified for a battery by its manufacturer. The output voltage falls to the cutoff voltage when the battery becomes "discharged". The nominal output voltage is always less than the open-circuit voltage produced when the battery is "charged". The temperature of a battery can affect the power it can deliver, where lower temperatures reduce power. Total energy delivered from a single charge cycle is affected by both the battery temperature and the power it delivers. If the temperature lowers or the power demand increases, the total energy delivered at the point of "discharge" is also reduced.

Battery discharge profiles are often described in terms of a factor of battery capacity. For example a battery with a nominal capacity quoted in ampere-hours (Ah) at a C/10 rated discharge current (derived in amperes) may safely provide a higher discharge current - and therefore higher power-to-weight ratio - but only with a lower energy capacity. Power-to-weight ratio for batteries is therefore less meaningful without reference to corresponding energy-to-weight ratio and cell temperature.

Battery type Volts Temp. Energy-to-weight ratio Power-to-weight ratio
Panasonic R03 AAA Zinc-carbon battery[29][30] 1.5V 20±2°C 47 kJ/kg 20mA to 0.9V 3.3 W/kg 20mA
88 kJ/kg 150mA to 0.9V 24 W/kg 150mA
Eagle-Picher SAR-10081 60Ah 22-cell Nickel hydrogen battery[31] 27.7V 10°C 192 kJ/kg C/2 to 22V 23 W/kg C/2
165 kJ/kg C/1 to 22V 46 W/kg C/1
Energizer 522 Prismatic Zn/MnO2 Alkaline battery[32] 9V 21°C 444 kJ/kg 25mA to 4.8V 4.9 W/kg 25mA
340 kJ/kg 100mA to 4.8V 19.7 W/kg 100mA
221 kJ/kg 500mA to 4.8V 99 W/kg 500mA
Panasonic HHR900D 9.25Ah Nickel metal hydride battery[33] 1.2V 20°C 209.65 kJ/kg to 0.7V 11.7 W/kg C/5
58.2 W/kg C/1
116 W/kg 2C
Energizer CH35 C 1.8Ah Nickel-cadmium battery[34] 1.2V 21°C 152 kJ/kg C/10 to 1V 4 W/kg C/10
147.1 kJ/kg 5C to 1V 200 W/kg 5C
Firefly Energy Oasis FF12D1-G31 6-cell 105Ah VRLA battery[35] 12V 25°C 142 kJ/kg C/10 to 7.2V 4 W/kg C/10
-18°C 7 kJ/kg CCA to 7.2V 234 W/kg CCA (625A)
0°C 9 kJ/kg CA to 7.2V 300 W/kg CA (800A)
Panasonic CGA103450A 1.95Ah Lithium ion battery[36] 3.7V 20°C 666 kJ/kg C/5.3 to 2.75V 35 W/kg C/5.3
0°C 633 kJ/kg C/1 to 2.75V 176 W/kg C/1
20°C 655 kJ/kg C/1 to 2.75V 182 W/kg C/1
20°C 641 kJ/kg 2C to 2.75V 356 W/kg 2C
Maxell / Yuasa / AIST Nickel metal hydride lab prototype [37] 45°C 980 W/kg
Ionix Power Systems Li-Mn2O4 Lithium ion battery lab prototype [38] lab 270 kJ/kg 1700 W/kg
lab 29 kJ/kg 4900 W/kg
A123 Systems 26650 Cell 2.3Ah LiFePO4 Lithium ion battery[39][40] 3.3V -20°C 347 kJ/kg C/1 to 2V 108 W/kg C/1
0°C 371 kJ/kg C/1 to 2V 108 W/kg C/1
25°C 390 kJ/kg C/1 to 2V 108 W/kg C/1
25°C 390 kJ/kg 27C to 2V 3300 W/kg 27C
25°C 57 kJ/kg 32C to 2V 5657 W/kg 32C

#### Fuel cell Stacks and Flow cell Batteries

Fuel cell type Dry weight Power-to-weight ratio
Ceramic Fuel Cells BlueGen MG 2.0 CHP SOFC[41] 200 kg 10 W/kg
15 W/kg CHP
MTU Friedrichshafen 240 kW MCFC HotModule 2006 20 t 12 W/kg
Smart Fuel Cell Jenny 600S 25W DMFC [42] 1.7 kg 14.7 W/kg
UTC Power PureCell 400 kW PAFC[43] 27,216 kg 14.7 W/kg
GEFC 50V50A-VRB Vanadium redox battery [44] 80 kg 31.3 W/kg (125 W/kg peak)
UTC Power Space Shuttle orbiter 12 kW AFC[45] 122 kg 98 W/kg
Ballard Power Systems FCgen-1030 1.2 kW CHP PEMFC[46] 12 kg 100 W/kg
Ballard Power Systems FCvelocity-HD6 150 kW PEMFC[46] 400 kg 375 W/kg
Honda 2003 43 kW FC Stack PEMFC[47] 43 kg 1000 W/kg
Lynntech, Inc. PEMFC lab prototype[48] 347 g 1,500 W/kg

### Photovoltaics

Photovoltaic Panel type Power-to-weight ratio
Thyssen Solartec 128W Nanocrystalline Si Triplejunction PV module[49] 6 W/kg
Suntech/UNSW HiPerforma PLUTO220-Udm 220W Ga-F22 Polycrystalline Si PV module[50] 13.1 W/kg STP
9.64 W/kg nominal
Global Solar PN16015A 62W CIGS polycrystalline thin film PV module[51] 40 W/kg
Able (AEC) PUMA 6 kW GaInP/GaAs/Ge-on-Ge Triplejunction PV array [52] 65 W/kg
Believed possible ~333 W/kg[53]

### Vehicles

Power-to-weight ratios for vehicles are usually calculated using curb weight (for cars) or wet weight (for motorcycles) - in other words, excluding weight of the driver and any cargo. This could be slightly misleading, especially with regard to motorcycles, where the driver might weigh 1/3 to 1/2 as much as the vehicle itself.

#### Utility and Practical vehicles

Most vehicles are designed to meet passenger comfort and cargo carrying requirements. Different designs trade off power-to-weight ratio to increase comfort, cargo space, fuel economy, emissions control, energy security and endurance. Reduced drag and lower rolling resistance in a vehicle design can facilitate increased cargo space without increase in the (zero cargo) power-to-weight ratio. This increases the role flexibility of the vehicle. Energy security considerations can trade off power (typically decreased) and weight (typically increased), and therefore power-to-weight ratio, for fuel flexibility or drive-train hybridisation. Some utility and practical vehicle variants such as hot hatches and sports-utility vehicles reconfigure power (typically increased) and weight to provide the perception of sports car like performance or for other psychological benefit.

##### Notable low ratio
Vehicle Power Weight Power-to-weight ratio
Benz Patent Motorwagen 954cc 1886 [54] 560 W / 0.75 bhp 265 kg / 584 lb 2.1 W/kg / 779 lb/hp
Stephenson's Rocket 0-2-2 steam locomotive with tender 1829 [55] 15 kW / 20 bhp 4,320 kg / 9524 lb 3.5 W/kg / 476 lb/hp
CBQ Zephyr streamliner diesel locomotive with railcars 1934[56] 492 kW / 660 bhp 94 t / 208,000 lb 5.21 W/kg / 315 lb/hp
Force Motors Minidor Diesel 499cc auto rickshaw[57][58] 6.6 kW / 8.8 bhp 700 kg / 1543 lb 9 W/kg / 175 lb/hp
PRR Q2 4-4-6-4 steam locomotive with tender 1944 5,956 kW / 7,987 bhp 475.9 t / 1,049,100 lb 12.5 W/kg / 131 lb/hp
TGV BR Class 373 high-speed locomotive 1993 12,240 kW / 16,414 bhp 816 t / 1,798,972 lb 15 W/kg / 110 lb/hp
BR Class 43 high-speed diesel electric locomotive 1975 1,678 kW / 2,250 bhp 70.25 t / 154,875 lb 23.9 W/kg / 69 lb/hp
GE AC6000CW diesel electric locomotive 1996 4,660 kW / 6,250 bhp 192 t / 423,000 lb 24.3 W/kg / 68 lb/hp
BR Class 55 Napier Deltic diesel electric locomotive 1961 2,460 kW / 3,300 bhp 101 t / 222,667 lb 24.4 W/kg / 68 lb/hp
International CXT 2004 [59] 164 kW / 220 bhp 6,577 kg / 14500 lb 25 W/kg / 66 lb/hp
Ford Model T 2.9L flex-fuel 1908 15 kW / 20 bhp 540 kg / 1,200 lb 28 W/kg / 60 lb/hp
Messerschmitt KR200 Kabinenroller 191cc 1955 6 kW / 8.2 bhp 230 kg / 506 lb 30 W/kg / 50 lb/hp
Wright Flyer 1903 9 kW / 12 bhp 274 kg / 605 lb 33 W/kg / 50 lb/hp
Tata Nano 624 cc 2008 26 kW / 35 bhp 635 kg / 1,400 lb 41 W/kg / 40 lb/hp
Suzuki MightyBoy 543cc 1988 23 kW / 31 bhp 550 kg / 1,213 lb 42 W/kg / 39 lb/hp
Holden FJ 2160cc 1953 [60] 45 kW / 60 bhp 1,012 kg / 2,250 lb 44 W/kg / 38 lb/hp
Chevrolet Kodiak/GMC Topkick LYE 6.6L[1][61] 246 kW / 330 bhp 5126 kg / 11,300 lb 48 W/kg / 34 lb/hp
Suzuki Alto 796cc 2000 35 kW / 46 bhp 720 kg / 1,587 lb 49 W/kg / 35 lb/hp
Land Rover Defender 2.4L 1990[62] 90 kW / 121 bhp 1,837 kg / 4,050 lb 49 W/kg / 33 lb/hp
##### Common power
Vehicle Power Weight Power-to-weight ratio
Toyota Prius 1.8L 2010 (petrol only)[63] 73 kW / 98 bhp 1380 kg / 3042 lb 53 W/kg / 31 lb/hp
Bajaj Platina Naked 100cc 2006[64] 6 kW / 8 bhp 113 kg / 249 lb 53 W/kg / 31 lb/hp
Subaru R2 type S 2003[65] 47 kW / 63 bhp 830 kg / 1830 lb 57 W/kg / 29 lb/hp
Ford Fiesta ECOnetic 1.6L TDCi 5dr 2009[66] 66 kW / 89 bhp 1155 kg / 2546 lb 57 W/kg / 29 lb/hp
Ford Focus ECOnetic 1.6L TDCi 5dr Hatch 2009[67] 81 kW / 108 bhp 1357 kg / 2992 lb 60 W/kg / 27 lb/hp
Ford Focus 1.8L Zetec S TDCi 5dr Hatch 2009[68] 84 kW / 113 bhp 1370 kg / 3020 lb 61 W/kg / 27 lb/hp
Honda FCX Clarity 4 kg Hydrogen 2008[69] 100 kW / 134 bhp 1600 kg / 3528 lb 63 W/kg / 26 lb/hp
Hummer H1 6.6L V8 2006[70] 224 kW / 300 bhp 3559 kg / 7847 lb 63 W/kg / 26 lb/hp
Audi A2 1.4L TDI 90 type S 2003[71] 66 kW / 89 bhp 1030 kg / 2270 lb 64 W/kg / 25 lb/hp
Mini (new) Cooper 1.6D 2007[72] 81 kW / 108 bhp 1185 kg / 2612 lb 68 W/kg / 24 lb/hp
Toyota Prius 1.8L 2010 (electric boost)[63] 100 kW / 134 bhp 1380 kg / 3042 lb 72 W/kg / 23 lb/hp
Ford Focus 2.0L Zetec S TDCi 5dr Hatch 2009[73] 100 kW / 134 bhp 1370 kg / 3020 lb 73 W/kg / 23 lb/hp
Ford Focus 2.0L Zetec S 5dr Hatch 2009[74] 107 kW / 143 bhp 1327 kg / 2926 lb 81 W/kg / 20 lb/hp
Fiat Grande Punto 1.6L Multijet 120 2005 [75] 88 kW / 118 bhp 1075 kg / 2370 lb 82 W/kg / 20 lb/hp
Mini (classic) 1275GT 1969 57 kW / 76 bhp 686 kg / 1512 lb 83 W/kg / 20 lb/hp
Subaru Legacy/Liberty 2.0R 2005[76] 121 kW / 162 bhp 1370 kg / 3020 lb 88 W/kg / 19 lb/hp
Subaru Outback 2.5i 2008[77] 130.5 kW / 175 bhp 1430 kg / 3153 lb 91 W/kg / 18 lb/hp
Smart Fortwo 1.0L Bradbus 2009[78] 72 kW / 97 bhp 780 kg / 1720 lb 92 W/kg / 18 lb/hp
Ford Focus 2.0 auto 2007[79] 104.4 kW / 140 bhp 1198 kg / 2641 lb 94 W/kg / 19 lb/hp
Toyota Hilux V6 DOHC 4L 4x2 Single Cab Pickup ute 2009[80] 175 kW / 235 bhp 1555 kg / 3248 lb 113 W/kg / 15 lb/hp
##### Performance luxury, roadsters and mild sports

Some utility and practical vehicles are designed for, as BMW would say[81], sheer driving pleasure. Increased engine performance is a consideration, but also other features associated with luxury vehicles. Longitudinal engines are common. Bodies vary from hot hatches, sedans (saloons), coupés, convertibles and roadsters. Mid-range dual-sport and cruiser motorcycles tend to have similar power-to-weight ratios.

Vehicle Power Weight Power-to-weight ratio
Mini (new) Cooper 1.6T S JCW 2008[82] 155 kW / 208 bhp 1205 kg / 2657 lb 129 W/kg / 13 lb/hp
Mazda RX-8 1.3L Wankel 2003 184 kW / 247 bhp 1309 kg / 2888 lb 141 W/kg / 12 lb/hp
GMH Caprice / GMC Caprice / Buick Park Avenue / Daewoo Veritas 6L V8 2007[83] 270 kW / 362 bhp 1891 kg / 4170 lb 143 W/kg / 12 lb/hp
Kawasaki KLR650 Gasoline DualSport 650cc 26 kW / 35 bhp 182 kg / 401 lb 143 W/kg / 11 lb/hp
NATO HTC M1030M1 Diesel/Jet fuel DualSport 670cc [84] 26 kW / 35 bhp 182 kg / 401 lb 143 W/kg / 11 lb/hp
Harley-Davidson FLSTF Softail Fat Boy Cruiser 1584 cc 2009[85] 47 kW / 63 bhp 324 kg / 714 lb 145 W/kg / 11.3 lb/hp
BMW 7 Series 760Li 6L V12 2006[86] 327 kW / 439 bhp 2250 kg / 4960 lb 145 W/kg / 11 lb/hp
Subaru Impreza WRX STi 2.0L 2008[87] 227 kW / 304 bhp 1530 kg / 3373 lb 148 W/kg / 11 lb/hp
Tesla Roadster 2008 185 kW / 248 bhp 1235 kg / 2723 lb 150 W/kg / 11 lb/hp
GMH HSV Clubsport / GMV VXR8 / GMC CSV CR8 / Pontiac G8 6L V8 2006[88] 317 kW / 425 bhp 1831 kg / 4037 lb 173 W/kg / 9.5 lb/hp

#### Sports and Flight vehicles

Power-to-weight ratio is an important vehicle characteristic that affects the acceleration and handling - and therefore the driving enjoyment - of any sports vehicle. Flight vehicles also depend on high power-to-weight ratio to achieve sufficient lift.

Vehicle Power Weight Power-to-weight ratio
Lotus Elise SC 2008 163 kW / 218 bhp 910 kg / 2006 lb 179 W/kg / 9 lb/hp
Ferrari Testarossa 1984 291 kW / 390 bhp 1506 kg / 3320 lb 193 W/kg / 9 lb/hp
Artega GT[89] 220 kW / 300 bhp 1100 kg / 2425 lb 200 W/kg / 8 lb/hp
Lotus Exige GT3 2006[90] 202.1 kW / 271 bhp 980 kg / 2160 lb 206 W/kg / 8 lb/hp
Chevrolet Corvette C6[91] 321 kW / 430 bhp 1441 kg / 3177 lb 223 W/kg / 7 lb/hp
Suzuki DL650 V-Strom V-Twin DualSport 650cc 50 kW / 67 bhp 194 kg / 427 lb 258 W/kg / 6.4 lb/hp
Chevrolet Corvette C6 Z06[91] 376 kW / 505 bhp 1421 kg / 3133 lb 265 W/kg / 6 lb/hp
Porsche 911 GT2 2007 390 kW / 523 bhp 1440 kg / 3200 lb 271 W/kg / 6.1 lb/hp
McLaren F1 GT 1997[92] 467.6 kW / 627 bhp 1220 kg / 2690 lb 403 W/kg / 4 lb/hp
Supermarine Spitfire Fighter aircraft 1936 1,096 kW / 1,470 bhp 2,309 kg / 5,090 lb 475 W/kg / 3.46 lb/hp
Messerschmitt Bf 109 Fighter aircraft 1935 1,085 kW / 1,455 bhp 2,247 kg / 4,954 lb 483 W/kg / 3.40 lb/hp
Thunderbolt Land speed record car 3504 kW / 4700 bhp 7 t / 15432 lb 500 W/kg / 3.28 lb/hp
Ferrari FXX 2005 597 kW / 801 bhp 1155 kg / 2546 lb 517 W/kg / 3.2 lb/hp
Polaris Industries Assault Snowmobile 2009[93] 115 kW / 154 bhp 221 kg / 487 lb 523 W/kg / 3.16 lb/hp
Ultima GTR 720 2006[94] 536.9 kW / 720 bhp 920 kg / 2183 lb 583 W/kg / 3 lb/hp
Honda CBR1000RR 2009 133 kW / 178 bhp 199 kg / 439 lb 668 W/kg / 2.5 lb/hp
KillaCycle Drag racing electric motorcycle 260 kW / 350 bhp 281 kg / 619 lb 925 W/kg / 1.77 lb/hp
MTT Turbine Superbike 2008[95] 213.3 kW / 286 bhp 227 kg / 500 lb 940 W/kg / 1.75 lb/hp
BMW Williams FW27 Formula One 2005[96] 690 kW / 925 bhp 600 kg / 1323 lb 1150 W/kg / 1.43 lb/hp
Honda RC211V MotoGP 2004-6 176.73 kW / 237 bhp 148 kg / 326 lb 1194 W/kg / 1.37 lb/hp
Boeing 747-300[10] at Mach 0.84 cruise, 35,000ft altitude 245 MW / 328,656 bhp 178.1 t / 392,800 lb 1376 W/kg / 1.20 lb/hp
Space Shuttle Endeavour (OV-105)[16][97] 190 MW / 255,000 bhp 78 t / 172,000 lb 2437 W/kg / 0.7 lb/hp
Aérospatiale/BAC Concorde 1969 at Mach 2.02 supercruise full thrust 330 MW / 443,143 hp 78.7 t / 173,500 lb 4199 W/kg / 0.39 lb/hp
Thrust Super Sonic Car 82 MW / 110,000 bhp 10.5 t / 23149 lb 7812 W/kg / 0.21 lb/hp
F-35 Lightning II Multirole combat aircraft 2006 at Mach 1.67 full thrust 110 MW / 146,922 hp 13,300 kg / 29,300 lb 8238 W/kg / 0.20 lb/hp
Sukhoi Su-35BM Multirole combat aircraft 2008 at Mach 2.25 full thrust 188.5 MW / 252,842 hp 18,400 kg / 40,500 lb 10,247 W/kg / 0.16 lb/hp
F-22 Raptor Fighter aircraft 1990 at Mach 2.25, 156kN thrust[98] 209 MW / 280,095 hp 19,700 kg / 43,430 lb 10,602 W/kg / 0.16 lb/hp
Space Shuttle Endeavour (OV-105)[16][97] with SLWT and 2 SRBs[99][100][101] 33 GW / 44,000,000 bhp 280 t / 616,500 lb 118,000 W/kg / 0.014 lb/hp

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