How much horsepower does a semi-truck have?

In today’s blog post, we will answer the following question: How much horsepower does a semi-truck have? We will explain the importance of horsepower and torque for semis, but also the difference between the two. We will also review the most powerful semi-truck currently on the market. 

How much horsepower does a semi-truck have?

A semi-truck can have from 400 up to 600 horsepower, and an average of 1,000 to 2,000 lb-ft of torque. Semi-trucks need to have powerful engines in order to transport very heavy loads, and high horsepower and torque mean better performance overall. 

A semi-truck is short for a semi-trailer truck, and it is called that way because its structure is composed of a semi-trailer for carrying the cargo and a semi-tractor for the engine power.  The term semi-trailer derives from the fact that the vehicle unloads part of its weight on its axles and starts on the fifth wheel of the road tractor that pulls it; therefore, from a physical point of view, it is only half towed.

What is horsepower and why does it matter for a semi-truck?

In mathematical terms, horsepower is a measure of work that is used to calculate the force and energy necessary to move an object and, at the same time, to assess the displacement of that object in the direction that the force is being exerted.

Ultimately, when it comes to measuring top speed and acceleration, horsepower has to be taken into account, as it is the figure that explains how much an engine manages to move in a given period of time. So if you want to go and accelerate faster, you will need more horsepower.

In case you would like to know the measure of horsepower, a horsepower equals 33,000 pound-feet per minute or 4562 kg/m per minute.

What is torque and why does it matter for a semi-truck?

Torque is a torsional or rotational force produced by the crankshaft of an engine. The amount of torque produced is directly proportional to the air flowing through the motor.

The larger the motor, the more air it will pump out and therefore produce more torque. The more torque the truck you are considering buying has, the greater its ability to get the job done.

This force is what drives trucks to haul heavy loads on the move. Also, the higher this figure, the less fuel your truck will consume.

What is the difference between horsepower and torque?

Simply put, torque is the force or ability to do work, while power (horsepower or HP) is how quickly a strenuous task can be accomplished.

Think of the difference between a racing car and a semi-truck. The former produces an enormous amount of horsepower, but its torque will be used to accelerate and have more momentum since it is not doing some kind of work. When this happens, you will have the power you need for speed.

A semi-truck, on the other hand, will require power to achieve greater strength and thus transport what it needs. It may not reach high speeds, but it will carry large amounts of weight.

Let’s see if you understand. An A car has 200 horsepower and a torque of 100-foot pounds, while a B car has 100 horsepower, but torque of 200 foot-pounds. Which of the two will go faster? If your answer was car A, then you were correct.

The importance of torque and horsepower for semi-trucks

Torque and power play an integral role in the automotive market. The numbers are emphasized as ways to illustrate what a cargo truck can do. In reality, these components are more important than most consumers realize. How they function in the world of driving and transportation is defined by how a vehicle’s design allows the two concepts to work together.

Torque and horsepower are produced by the engine when you turn the key and press the accelerator. Ignited air and fuel in the combustion chambers cause the crankshaft, transmission, and driveshafts to rotate, initiating energy conversion.

The next time you see a vehicle advertised or are considering buying a semi-truck, think about what it means when it comes to horsepower and torque. There is a relationship between the two: they cannot exist without each other, but they represent very different aspects that allow a truck to function.

What is the most powerful semi-truck?

The most powerful semi-truck currently on the market is the Volvo FH16, as it offers unique performance and fuel economy. This semi-truck is 700 hp of pure diesel muscle.

The Volvo FH16 has rigid and tractor versions, with sleeping cabins, Globetrotter, Globetrotter XL. The maximum authorized mass of the set is 100 tons, so it can handle really wild loads. It is a truck designed for heavy and demanding transport, and for that, it needs a lot of power.

The D16G engine has three power ratings:

  • 540 hp (2,650 Nm max.)
  • 600 hp (2,800 Nm max.)
  • 700 hp (3,150 Nm max). 

In other words, the most powerful have the same thrust force as three Bugatti Veyrons, which would add 3003 hp. They are six cylinders in line, with a filling capacity of 16.1 litres. A single turbo feeds them and has a heat exchanger (intercooler).

This powerful engine meets Euro V emission regulations thanks to the use of SCR (selective catalytic reduction), with low emissions of nitrogen oxides (NOx). 90% of the torque is available in seconds. It has a single-cylinder head, overhead rocker shaft, four valves per cylinder and electronically controlled injection, with the timing at the rear of the engine.

The bottom line

The horsepower of a semi-trailer indicates the operability of a vehicle. It refers to how much force is produced per second, this force is what a vehicle uses to accelerate, so more horsepower gives faster acceleration. How much horsepower you actually need depends on the weight of the semi-trailer and the speed you need. 

Torque is the energy developed by a heat engine, it produces a force that is transmitted to the connecting rod and the crankshaft. The reciprocating movement of the pistons is thus transformed into a circular movement; which is called torque or torque.

Inside the engine, the combustion gases generate a pressure inside the cylinders that pushes the pistons with a certain downward force that is transmitted towards the crankshaft, making it rotate due to the generated torque.

We hope that now it is more clear what horsepower and torque are, and why they matter for the optimal operation of a semi-truck. 

FAQ on How much horsepower does a semi-truck have?

How much horsepower do busses have?

School buses can have from 235 up to 450 horsepower, depending on the engine. The most common brands of Skoolie engines are Cummins, Caterpillar and International Navistar.

Which is more important: horsepower or torque?

Both horsepower and torque are important. It is obvious that the more power a car develops, the better it will manage the whole, but there are many more important variables. The strength of a vehicle, and therefore its towing capacity, is determined by its engine torque, not by power.

What is the difference between a trailer and a semi-trailer?

The difference between a trailer and a semi-trailer is in the way they are built, their carrying capacity and their purpose of use. Thus, trailers are vehicles without an engine, which are towed or pulled by a tow vehicle (rigid truck). Semi-trailers are vehicles without an engine hooked or coupled on the 5th wheel of a tractor head resting part of its weight on it.

​​Why is it called a semi-truck?

A semi-truck is short for a semi-trailer truck, and it is called that way because its structure is composed of a semi-trailer for carrying the cargo and a semi-tractor for the engine power. 

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