Torque vs Power
The performance of an engine is described by the torque and power. Many of us do not know the difference between the two. So then when choosing a car, obviously the higher the values, the better the engine. But what actually are they?
For a car, the torque is normally measured in ft/lbs, and power is normally measured in brake horsepower (bhp). In its simplest mechanics form, power determines how fast your car can go. Torque is the 'pulling power' and determines how fast that speed can be reached. The two are dependable on a mix of variables such as bore and stroke, transmission gearing or compression ratio.
Very often while test driving a car, we feel the car is effortless in trying to get to a certain speed. That is when the torque comes into play. Manufacturers however do play around with the timing of torque and horsepower at different ranges of rpm. With cars tuned to have high low-end torque, the car will feel effortless to accelerate in stop-and-go traffics. Hence it gives you that powerful feeling. However when it comes to higher range of the rpm, the torque decreases and it will seem the car tend to be weak at higher speeds.
Let's get into more details. A car manufacturer can claim that their 3.5L V6 engines can produce 300 bhp. Yet on a test, it was found to have only 240 bhp. Did they cheat? No. The disparities between the two numbers is based on the fact that one is a gross horsepower rating while the other corresponds to the wheel-driven horsepower.
Gross horsepower is the engine output measured at the flywheel without the engine installed in a vehicle. Wheel-driven horsepower, also known as Net horsepower, is done by tests when the vehicle is put on a large roller, and power measured at the flywheel when the wheels are accelerated to redline in first or second gear.
For gross horsepower, since the engine has no load on it, all of its power can be used for making horsepower. Because there is frictional loss in the engine as well as in the wheel-driven contact, net horsepower is always lower than gross horsepower. The Japanese cars normally uses 'Ps' to measure horsepower, and is a closer margin between gross horsepower and net horsepower.
So, 280bhp is faster (top speed) than 240 bhp, 230 ft/lbs accelerates faster than 200 ft/lbs. But a car with 280 bhp 200ft/lbs may not necessarily beat a car with 240bhp 230ft/lbs in a short race.
For a car, the torque is normally measured in ft/lbs, and power is normally measured in brake horsepower (bhp). In its simplest mechanics form, power determines how fast your car can go. Torque is the 'pulling power' and determines how fast that speed can be reached. The two are dependable on a mix of variables such as bore and stroke, transmission gearing or compression ratio.
Very often while test driving a car, we feel the car is effortless in trying to get to a certain speed. That is when the torque comes into play. Manufacturers however do play around with the timing of torque and horsepower at different ranges of rpm. With cars tuned to have high low-end torque, the car will feel effortless to accelerate in stop-and-go traffics. Hence it gives you that powerful feeling. However when it comes to higher range of the rpm, the torque decreases and it will seem the car tend to be weak at higher speeds.
Let's get into more details. A car manufacturer can claim that their 3.5L V6 engines can produce 300 bhp. Yet on a test, it was found to have only 240 bhp. Did they cheat? No. The disparities between the two numbers is based on the fact that one is a gross horsepower rating while the other corresponds to the wheel-driven horsepower.
Gross horsepower is the engine output measured at the flywheel without the engine installed in a vehicle. Wheel-driven horsepower, also known as Net horsepower, is done by tests when the vehicle is put on a large roller, and power measured at the flywheel when the wheels are accelerated to redline in first or second gear.
For gross horsepower, since the engine has no load on it, all of its power can be used for making horsepower. Because there is frictional loss in the engine as well as in the wheel-driven contact, net horsepower is always lower than gross horsepower. The Japanese cars normally uses 'Ps' to measure horsepower, and is a closer margin between gross horsepower and net horsepower.
So, 280bhp is faster (top speed) than 240 bhp, 230 ft/lbs accelerates faster than 200 ft/lbs. But a car with 280 bhp 200ft/lbs may not necessarily beat a car with 240bhp 230ft/lbs in a short race.
posted by Chalks at
6:26 PM
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