What is the advantage of a bigger engine though it has lower hp?

To supplement their answers, a car can be re-geared to take advantage of the increased torque on the diesel engine.

While the high-horsepower can have a short 6:1 axle ratio, the diesel has enough low-end torque that they can put a tall 3.5:1 axle in, which will make the different in horsepower negligible.

Diesels have low horsepower because they run at lower speeds, rarely going above 3,000rpm compared to 7500 for a small gasoline engine

When it comes to diesel its all about the torque bud. Allthough it may not produce much H.P. it most likley produces double or more torque comparitive to H.P. So this is somthing most people dont know, H.P. is a made up measurement of an engines power, it was a formula made by a man who was selling a 1 H.P. engine back in the erly 1900's. One H.P. is equal to the power nessicary to move 550 Lbs. one foot in one second. The more solid spec too look at is torque (which is an actually physical measurement (torque is a twisting force)

diesel engine make low horse power compared to similar gas engines of the same displacement,........however the diesel engine make TONS more torque. When looking at a diesl forget all about the H.P. and look at what the lb. ft. of torque the motor produces.

what he said......