Why do diesel engines have more torque than horsepower?

The issue is that diesel engines, while they produce a whole lot of torque, cannot rev nearly as high as comparable gasoline engines. And since:


horsepower = (torque*engine speed) / 5252


If your engine won't rev past 3000 rpm, you'll always have less peak horsepower than torque. As for why they can't rev higher, they're limited by either the burn rate of the fuel per ignition stroke, the mechanical limitations due to the longer piston rods/crank lobes, or both.