Diesel Engines are More Efficient than Gas Engines
• Diesel fuel contains on the order of 10% more energy content per volumetric unit than gasoline; diesel fuel has a higher energy density.
• Turbocharged diesel engines produce less waste heat through the exhaust system. Think conservation of energy - heat that is expelled through the exhaust system is not converted into mechanical energy. A turbocharger converts wasted heat energy into useful mechanical energy.
• Diesels produce higher peak torque than gas engines and do so at lower operating speeds, even under light throttle inputs.
• Diesel engines can operate at within a board range of air-to-fuel ratios, while a gas engine is restricted to a stoichiometric ratio of 14.7:1. Running a leaner mixture at idle and low load driving conditions reduces fuel consumption.
• A comparatively sized diesel engine can be expected to achieve 20-30% better fuel economy than a gas engine, sometimes more when towing.
Lower Cost of Ownership
Though diesel fuel is marginally more expensive, standard service procedures are more costly, and diesel engines are typically purchased at a higher initial cost, diesel engines are cost effective to own in the long run.
• Lack of ignition system, diesel engines utilize a compression ignition process. Ignition coils can run several hundred dollars for a set not including replacement labor, and are a common wear item in gas engines.
• Diesels have long service intervals, often greater than or equal to a comparable gas engine.
• Diesel provides lubrication to fuel system components. Unlike gasoline, which is a solvent, diesel fuel lubricates any item it comes into contact with.
• Diesel engines far outlive gas engines. A diesel should be expected to operate several hundred thousand miles before major repairs or overhaul is necessary. The robust design of a diesel engine means that the engine often outlasts the vehicle that it powers! At 150,000 miles, when you gas engine begins to grow tired, the diesel is finally broken in.
Longevity - Diesel Engines Last Longer
• Diesel engines are robust and rugged. The larger, stronger engine components contribute to a longer engine life.
• Diesel engines operate at lower combustion temperatures.
• Diesel engines operate at lower engine speeds, which increases the life of reciprocating parts.
Diesel Engines Produce Peak Torque at Low RPMs
Diesel engines produce more torque than an equivalent gasoline engine, and do so at lower RPMs. Not only does this contribute to improved fuel economy, but makes the diesel engine the perfect tow machine. High torque output at low RPMs is why diesels are the preferred engine for construction, agriculture, and towing applications.
Diesel Engines are More Versatile
Diesel engines are used in everything from commuter cars to locomotives. There versatility allows the same engine to provide outstanding fuel economy in a number of driving conditions and tow payloads that would present a challenge for a comparable gas engine. Diesel engines can be used in mines and confined spaces as a result of low CO emissions. They run equally well in sub-zero and hot climates, and turbocharged diesel engines don't suffer from the same power loss as naturally aspirated gas engines in high altitudes.
Diesel Engines Can be Easily Modified
Dollar for dollar, you can get higher performance out a turbodiesel than any production gas engine. Modern diesels can be tuned to produce significantly more power and torque over stock levels with factory engine components. For most production gas engines, adding a significant amount power typically requires a significant investment in both performance enhancing products and strengthening of the engine.