I’m thinking of a sports car vs. tow truck. An engine built for speed, and an engine built for power (torque). How do the engines react differently under extreme conditions? I.e being pushed to the max. What’s built different? Etc.
In: 3108
The chief difference is in the amount of power you get per pound of engine. We determine engine power by multiplying engine speed by the amount of torque it produces.
An engine designed for a fast vehicle will optimize for less weight. Typically it will burn gasoline because the engine can be made less robustly. These engines can shed weight further (and still make power) by spinning faster. A working engine on the other hand will optimized for things like durability, efficiency, or drivability. These engines will spin more slowly because it makes sense for the use case. When they spin more slowly they need to make more torque to make the same power vs a low torque but high revving engine.
An example of this: the engine in a BMW super bike weighs 150lbs and makes 180hp. It makes that power at 14000 RPM. A 6BT Cummins might also make 180hp but it weighs closer to 1100lbs. That diesel will redline closer to 2900 RPM. The bike engine is meant for racing at the cost of efficiency and longevity, the diesel is meant to be more efficient and easier to drive.
I’m thinking of a sports car vs. tow truck. An engine built for speed, and an engine built for power (torque). How do the engines react differently under extreme conditions? I.e being pushed to the max. What’s built different? Etc.
In: 3108
The chief difference is in the amount of power you get per pound of engine. We determine engine power by multiplying engine speed by the amount of torque it produces.
An engine designed for a fast vehicle will optimize for less weight. Typically it will burn gasoline because the engine can be made less robustly. These engines can shed weight further (and still make power) by spinning faster. A working engine on the other hand will optimized for things like durability, efficiency, or drivability. These engines will spin more slowly because it makes sense for the use case. When they spin more slowly they need to make more torque to make the same power vs a low torque but high revving engine.
An example of this: the engine in a BMW super bike weighs 150lbs and makes 180hp. It makes that power at 14000 RPM. A 6BT Cummins might also make 180hp but it weighs closer to 1100lbs. That diesel will redline closer to 2900 RPM. The bike engine is meant for racing at the cost of efficiency and longevity, the diesel is meant to be more efficient and easier to drive.
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