Best Fuel Mileage for Big Trucks
Most class eight semi trucks get between 6-8 miles per gallon (39 to 29 litres per 100km), whether empty or fully loaded; an empty truck may get 8mpg (29 litres/100km). Of course you want to get as close as you can to the upper numbers, since any savings in fuel is significant.
One option is to get a newer truck. The Volvo VN 780 is an efficient truck that offers 6.8 mpg so it can can save about $21,000 in fuel over five years (based on $4.15 per gallon of diesel with 3% yearly increase) - that's a significant savings with relatively effort if you are already looking for a newer truck.
When its not practical to get a new truck, start by reviewing your truck's maintenance records. If you don't have maintenance records, start keeping them - make sure each service record includes the date and your trucks VIN.
Your maintenance records are likely to help you spot some patterns that may help you figure out where to begin looking for fuel savings. For example, if you serviced your air conditioner three times last year, chances are high that your air conditioner is adding unnecessary load on your truck's engine and wasting fuel. Try to include all service in your maintenance record, including top-ups in tire pressure - even if all you note is the date you added air to tires. While you may have anecdotal evidence that one of your tires has a slow leak, there's nothing like empirical evidence (observations) to backup your hunch.
Regular maintenance not only extends the useful life of your truck, it also contributes to fuel savings. One study found that regular maintenance can save up to 10% in energy costs - again this is a relatively easy way to realize on-going savings without doing anything beyond regular maintenance.
A regular maintenance program starts with the basics. Measuring your truck's current fuel consumption so that you have a baseline to compare against later.
Check your tire pressure and record whenever you have to top-up any tire; under-inflated tires cause more drag than properly inflated tires. Also consider using Nitrogen as compared to regular air. Nitrogen does not expand and contract like regular air does, which keeps your tire pressure stable during temperature changes. You can add regular air to Nitrogen-filled tires if necessary.
Check the air filter; a clogged air filter makes your engine work harder to get the air it needs to draw for each firing of every piston. The air flow through a new air filter is also much cleaner than air flowing through a dirty air filter, which can contribute to longer engine life.
Change your oil as required. Changing your oil is probably the second most important regular maintenance you have to do for your truck (keeping your tires inflated properly is first). Check with the engine's manufacturer to know if you can use a semi-synthetic or synthetic oil instead of conventional oil. Synthetic oil offers a broad range of operating temperatures and tends to offer better lubricating capabilities as compared to conventional oils.
Use the Air Conditioning sparingly and prefer to use it on the highway instead of in heavy or slow moving traffic; your air conditioner is far more efficient when you're travelling at highway speeds.
Remove excess weight by carrying only what's necessary for each job. While it might be convenient to have a lot of extra tools on-hand, they extra weight really adds-up. Consider reusing some things for other purposes to avoid carrying a lot of specialized items.
Consider using a cold air intake system and a high-flow exhaust system and better airflow through the system not only improves fuel economy, it also improves horsepower.
Doing all of these things can boost your fuel efficiency,make your truck much more reliable in the long-run, and possibly extends the useable life of your truck, thereby increasing your return on investment.