When we want to purchase a car and want to see the brochures of the car, the car manufacturer will highlight the exterior feature, interior feature, comfort feature, infotainment feature and safety features. On the engine specification of the car whether on the internet or in the brochure given by the showroom they is two number that will attract the drivers and that is the horsepower (hp) and the Max torque(Nm). Although this numbers may or may not concern some user this number does represent the car engine power and the acceleration of the car engines. Today we will have a look on both of the horsepower and torque.
The horsepower of the car is the power that the car engines produce. The term horsepower was invented in 18th centuries by the steam engine designer James Watt. The torque is the rotating force of the engine that will provide more acceleration as more torque the greater the ability for the engine to perform its work. So the horsepower and the torque is the most important part of the engine in deciding the car power and the acceleration power.
Another thing that can be noticed in the engine specification is the naturally aspirated engine produce more horsepower but less torque with a higher cc or bigger engine but the turbo engines will provide the least horsepower but more torque with a smaller engine.
How both of the engines work? The naturally aspirated engine draws the air into the engine through the air intake. The benefits of this type of engine are it is more reliable and cheaper to maintain but to get a bigger output from the engine it needs a bigger engine. The turbo engine, on the other hand, can produce more power even with a smaller engine and less weight. The turbo force more air into the engine cylinders which can be mixed with more fuel to create more power. It will use the engine exhaust gas to compress more air into the engine. Many of the current car manufacturer even some of the sports car is using the turbo as it can deliver more power even with a smaller engine. Another benefit will reduce the weight of the car.
Now for a further understanding, we can look at the car comparisons on the image above. This image was taken from www.carbase.com as it displays the comparisons of the all the car from the aspirated engine and to the turbo engine. First, if we look at the Honda Accord G9 2.4 cc it had a high horsepower of 173hp and produces a torque of 225nm. Honda Accord is using the new Honda Earth Dream engines where it is an aspirated engine. The next two cars have turbo engines. The Volkswagen Passat with 1.8 cc produce least horsepower compare to Honda Accord with 158hp but produces more torque at 250nm. The Passat using the TFSI engines and also the DSG that helps to gain more torque on this car compare to Honda Accord. On the other hand, the BMW 320i new generation with 2.0cc produces a higher horsepower than Honda Accord at 184hp and even higher torque at 290nm. Another thing that can be noticed the aspirated engine of Honda Accord produces the least torque from a higher rpm while both of the Passat and BMW turbo produce a high torque with a low rpm.
On the other, the Toyota Camry Hybrid is also using aspirated engines but producing a higher torque with help of the electric motor as it is a hybrid model. If the electric motor is not there then the Camry only produces 158hp and 213nm. In this comparisons the cons of the aspirated engines can be seen as even with the higher cc it produces a less rotating force where the turbo engine produces more rotating force with a smaller size
Due to turbo engine forces air in the engine, it can produce more rotating force to the engine that can generate higher torque hence more power on the acceleration even with a smaller engine. However some of the sports cars manufacturer such as Ferrari, Lamborghini, Porsche, Maserati and many other still using the aspirated engine. They need to fix bigger engines that gave more horsepower an example the Porsche Carrera GT using an aspirated engine that gave a 604hp. Why the sports car is using the aspirated engine when the turbo engines can produce a higher power output with a smaller engine. The answer is to avoid the turbo lag. The turbo lag is a slower throttle response that happens when they are a delay in the exhaust system and the turbocharger to generate the necessary boost that is needed. In the sports car where the driver needs to have an adrenalin pumping experiencing does not like this kind of slower response a bit hence that is the reason for why sports car using the bigger aspirated engines as it does not have the turbo lag.
Some of the drivers will not prefer to use these details when purchasing a car depends on the driver preference as some will prefer to the exterior and the interior of the car, the space that the car provides them, the safety, maybe warranties, car reputation, dream cars, and mainly the expenditure abilities. For some drivers, they will prefer all the above and also the driving experience that can get while owning the car.
The drivers that enjoy a conform ride may prefer the aspirated engine car and the driver that want an adrenalin pumping may prefer the turbo engine car that provides more acceleration power. Simply for the daily commuting, the horsepower will give the power but the torque is the one that will provide the excitement that is needed while driving. The driver will like the joy when hitting the throttle hard and feel the power and speed of the car pushed them back to the edge of the seats. This is the thing that the torque will provide.
Simply the horsepower is the power of the engine and the feeling of acceleration is the thing that the torque provides.