If you’re considering buying a new vehicle, you have plenty of options. Factoring in the number of manufacturers, models, trim levels, and option packages, it can seem like there’s almost too many choices to make. Now, most people have an idea what they want. Perhaps a pickup truck, SUV, or a sedan.
Choosing a powertrain can be one of the most challenging decisions buyers make. Today, vehicles often have multiple powertrain options for each model. Do you choose a traditional gas engine, a turbocharged version, or perhaps you have a diesel engine available. Of all the engines, the diesel powertrain might be the least understood.
So, we’ve created this comparison between gas and diesel engines to help you understand the differences. We’ll show you the pros and cons of each to help you make an informed decision.
Different Combustion Processes for Gas and Diesel
One significant difference many people may not understand comes in how these two engines ignite the fuel. Both use internal combustion, but where the gas engine uses spark plugs, the diesel engine doesn’t. As the air-fuel mixture enters the cylinder of a gas engine, the spark plug emits a tiny spark to ignite the fuel, which then pushes the cylinder rod to turn the crankshaft.
The diesel engine uses compression ignition technology, compressing the air-fuel mixture until it ignites. This high level of compression requires significantly stronger engine components to support the process.
Diesel or Gas, Which Lasts Longer?
For decades, experts routinely claim that diesel engines out-perform their gas counterparts. In many ways there’s truth to this statement. Diesel engines have stronger construction, thanks to the thicker materials that handle the compression combustion, which naturally makes them durable.
It isn’t uncommon for a diesel engine to run for 200,000 miles, 300,000 miles, or more. Many diesel mechanics believe a diesel engine isn’t fully broken in until it reaches 100,000 miles.
However, a gas engine that doesn’t have significant load placed on it can last almost as long. Many gas engines now run well over 100,000 miles with the proper maintenance. You should consider the type of driving you plan on doing. For instance, if you need to tow heavy loads with a truck, a diesel engine probably makes more sense.
In most cases, diesel engines cost more to maintain than gas engines. For one, larger diesel engines require more engine oil, making a simple oil change more expensive. Diesel engines also have fuel and exhaust components with various filters and emissions systems that gas engines do not. These components wear out and need replacing, adding additional expenses.
In addition, modern diesel engines require diesel exhaust fluid (DEF). Diesel exhaust fluid breaks down the pollutants created by the combustion process. The system sprays the DEF into the exhaust before exiting the tailpipe.
Because diesel engines operate at a lower rpm, they experience less wear on engine components. The higher operation cost of diesel makes sense if you need to work your engine hard for long periods. Gas engines will likely have more breakdowns under these conditions.
Diesel engines produce more power than gasoline engines per the same size cylinder. For instance, an eight-cylinder gas engine puts out the same power as a six-cylinder diesel engine. Therefore, the diesel engine consumes less fuel.
In addition, diesel engines are more efficient at highway speeds, making the diesel engine a more efficient option if you plan on driving long distances often. If you need to tow and haul heavy loads, diesel engines also out-perform their gas counterparts with more power, but the efficiency drops below that of a gas engine.
Towing and Hauling
Diesel engines offer better towing performance than gas engines. Diesel engines produce more torque at lower rpm. That’s ideal for towing. Diesel engines get better mileage when heavily loaded, which adds to their appeal.
Many diesel engines on trucks include an integrated exhaust brake, which aids in controlling the truck and trailer, particularly when driving in heavy traffic or descending steep hills. The exhaust brake slows the engine using the turbo’s back pressure.
When comparing hauling ratings, gas engines nearly always have higher capacities than diesel engines. This higher capacity stems from the lighter gas powertrain. Simply put, the vehicle can only carry so much weight. A heavier diesel powertrain subtracts from that total. Still, if you consistently need to push your payload limits, a gas engine enables a higher payload.
Horsepower and Torque
When it comes to torque, the diesel engine beats the gas engine almost every time. In some cases, diesel engines in heavy-duty trucks put out 1,000 pound-feet of torque. The largest gas engines only approach 500 pound-feet of torque. So, if you’re planning heavy work on a consistent basis, a diesel engine clearly makes more sense.
In sedans, the diesel engine doesn’t need to tow or haul, but that torque still impacts performance. In most cases, the diesel engine delivers quicker acceleration than gas engines because they access that torque at lower rpm. However, the gas engine revs higher and faster, making it better for more spirited driving throughout the powerband.
For light-duty trucks, the diesel engines don’t offer a significant advantage over gas engines. While the diesel engine in a light-duty truck might put out over 300 pound-feet of torque, it produces less than 200 horsepower. Many light-duty truck gas engines produce up to 275 pound-feet of torque and around 300 horsepower.
In the end, choosing a diesel or gas engine comes down to usage. Understanding your driving needs will help you decide. At New Jersey State Auto Used Cars, we know the importance of choosing vehicle options wisely. That’s why we stock an expansive inventory of cars, trucks, and SUVs with varying powertrain configurations.
If you’re interested in upgrading your Jersey City commute with a quality gas or diesel powertrain, we invite you to browse our inventory online or stop by for a more personalized experience. One of our friendly, knowledgeable staff will show you the different options and let you take your favorite for a test drive.