Car enthusiasts look for many things when buying a car, from the vehicle’s overall look to its technical details. An important technicality considered is about the engine’s performance, which primarily depends on the weight to power ratio. This is where we use the weight to power ratio or PWR in cars.
What is the Weight to Power Ratio
Let’s establish the basics to get a hold of the weight to power ratio concept. First of all, keep in mind that all vehicles have different power and weight figures (unless they have the exact engine with the same tuning). To simplify, let’s break this down. For example, Ford Figo churns out 95 hp of power, has a 1.2 litre petrol engine and it weighs 1067 kgs (tentative).
On the other hand, Tata Altroz has a 1.2-litre turbo petrol engine that generates 100 hp max power and weighs 1130 kgs (tentative). Now, both these engines have almost similar displacement but the power figures differ. Car buyers will naturally pick the car with better performance.
In order to judge a car based on its performance, you need to figure out the weight to power ratio. We can calculate any vehicle’s power to weight ratio by dividing the power of the vehicle by its weight.
After you calculate this figure, the car with a higher ratio is the one with a more powerful engine.
How to Calculate Power to Weight Ratio
To calculate the power to weight ratio, you need to be certain about the following steps.
Step 1: Know Your Car’s Power Figures
Auto manufacturers mention the vehicle’s power figure (maximum power your car’s engine can produce) on the brochure. The car engine will naturally not make the high power daily but you get the gist of its performance with the help of power figures.
That said, if you can’t find figures on the brochure, power figures for engines of different car models are available on the internet. In order to calculate the power to weight ratio, you should be sure of your engine’s power figure.
Step 2: Know Your Car’s Weight
The second step is to know your car’s weight. You can find the engine’s weight on the car brochure or manual. If not, you can look for the weight figure of your car’s engine on the internet.
Please keep in mind that the curb weight is the weight that needs to be considered. Curb weight does not include the weight of the driver, passengers or luggage.
Power to Weight Ratio Formula
Finally, once you have both the figures, divide them to figure out which engine performs better. Calculate the weight to power ratio by dividing the engine power by the engine weight.
Formula: P/W
Let’s simplify this. Usually, a turbocharged V-8 diesel engine has an engine power of 250 horsepower and weight of 1,000 lb, dividing the two results in a power to weight ratio of 0.25 hp/lb.
Another example: Dodge Viper with a 450 hp engine power and accelerate 3,320 lbs. of weight, results in a power to weight ratio of 0.135 hp per 10 lbs.
What Does Power to Weight Ratio Have to Do With Performance
If you are wondering that less weight means more engine power, it depends on what performance means to you. For performance enthusiasts, speed and acceleration matter the most. They will always prefer cars with higher hp because more horsepower = more speed.
But one must also take other factors into consideration, such as how a car handles different road conditions. However, as far as sheer acceleration ability and speed are concerned – the higher your PWR in car, the better. Under this context, an ideal performance car is one that is lighter in curb weight but higher in horsepower.
Car Brands with Substantial Weight to Power Ratios
Following are some car models with substantial power to weight ratios.
- Hennessey Venom GT2: The engine churns out 1,500 hp, it weighs 2,685 lb. Dividing the two the engine’s power to weight in lb is 55.87 hp/lb and the power to weight in tons is 1230.52 hp/ton.
- 1971 McLaren M8F: The engine has a 740 hp, it weighs, 1,424 lb. Diving the two the engine’s power to weight ratio in lbs is 51.97 hp/lb and in tons: 1145.51 hp/ton.
- 1972 McLaren M20: The engine has a power of 787 hp, it weighs 1,521 lb. Diving the two the power to weight ratio in lbs is 51.74 hp/lb and in tons, it is: 1140.58 hp/ton.
- 1968 Ferrari 612 Canam: The engine churns out a power of 620 hp, it weighs 1,543 lb. The power to weight ratio in lbs is:40.17 hp/lb and the ratio in tons is: 885.57 hp/ton.
- 2006 Bugatti Veyron: The engine has a power of 987 hp, it weighs 4,162 lb. The power to weight ratio in lbs is 23.71hp/lb and in tons, it is: 490.45 hp/ton.
- Sauber Mercedes C291: The engine has a max power of Sauber Mercedes 640 hp, it weighs 1,654 lb. The power to weight ratio in lbs is 38.70 hp/lb and in tons, it is 853.33 hp/ton.
That is all about weight to power ratios. If you are in search of cars with higher power-to-weight ratios, explore a collection of used cars for sale in the UAE. You will find a variety of cars here with different engine specs and power-to-weight ratios. Also, you can learn more about increasing horsepower and modifications required for it.
For more on car parts and car anatomy as a whole stay tuned to your favourite auto blog.
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