Ask any car enthusiast about horsepower and chances are that you will get a blank look, a shrug of the shoulders and maybe a guess along the lines of “what is this horsepower about?”
In case you’ve ever wondered what a car’s horsepower means in real terms, fret no more.
ProPakistani brings you a guide which will help you understand what horsepower actually is, how significant it is, and finally how can you calculate your own car’s horsepower.
Lets get right into it.
What is Horsepower?
Horsepower, a term invented by the engineer James Watt, is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute.
Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower.
In this case, you’d have expended one horsepower-minute of energy.
Significance of Horsepower
We now know the meaning of horsepower but what does it represent?
Simply put, maximum horsepower determines the top speed of a car, as well as how fast it can accelerate to 60 mph.
It is important to note that horsepower alone doesn’t determine the top speed of your car. We also include the weight of the vehicle when determining that horsepower factor.
Additionally, horsepower affects a vehicle’s towing capacity, which is especially important for trucks.
Here’s what horsepower means for all the other aspects of your car.
- Performance & Acceleration
While horsepower can not be considered as a key factor for determining a car’s quality, it is a factor that a car’s performance greatly depends on. Acceleration time and speed are closely related to horsepower.
- Fuel Consumption
On the other hand, generally speaking, more horsepower means more fuel consumption. The higher the car’s horsepower, the lesser its fuel economy.
The durability of the car has no relation with horsepower whatsoever.
Here’s How You Can Calculate Your Car’s Horsepower
The easiest way to calculate the horsepower of your car is through a dynamometer. However, in Pakistan, dynamometers aren’t that common. You don’t need one if you want a simple way to calculate your car’s horsepower.
Follow these steps:
- Weigh your car with full fuel and the driver sitting in. Additionally:
- You can weigh your car at any commercial place that weighs trucks
- You can also use the information provided on the brochure of your car
- Mark the distance on the road, exactly for a quarter of a mile (roughly 1320 feet)
- You will need to start an acceleration run through the quarter mile you just marked.
- When crossing the end line, note down the speed of your car.
After doing that, you will have the weight and the speed of the car. Now use the following formula to get an estimate:
Horsepower = Weight x [(speed / 234)^3]
Suppose the weight of the car is 3000 lbs, and the car speed while crossing the end line was 110 mph. It would yield the following result:
Horsepower: 3000 x [(110 / 234)^3] = 311 bhp approximately.
After obtaining this result, estimate the drivetrain losses:
- 15% and 20% for manual and automatic gearboxes respectively
- Add 5% additional loss if the vehicle is a four wheel drive (FWD)
The peak output of the engine will be about 373 bhp.
Similarly, you can also calculate the torque of the car, since Torque = Horsepower / [(RPM* / 5252)].
- You can note down the RPM from your car’s HUD while crossing the quarter mile mark.
We’ll be covering more such informational auto-related guides and how-tos in the future as well, so don’t forget to check back.