How Do I Improve MPG in a 6 Liter Silverado?by Skip Shelton
The 6.0 liter Chevrolet Vortec engine displaces 364 cubic inches. The engine is installed in the Cadillac Escalade line, select Chevrolet trucks (Silverado and SS) and select GMC trucks. The engine power, fuel trims, gearing, air intakes and vehicle exhaust systems all contribute to the established fuel economy ratings of the vehicles. Actual calculated fuel economy depends primarily on individual driving habits, environmental conditions, maintenance and upkeep and aftermarket additions, all of which might either enhance or degrade mileage.
Fully inflate the tires to the recommended cold psi. When tire pressure is low (even on a single tire), mileage can be reduced by as much as 15 percent. Monitor tires at significant weather changes and after extended use. Maintaining proper cold tire pressure will reduce the drag on the vehicle and require less engine work to accelerate and maintain engine speeds.
Exchange stock fluids with quality synthetics. Engine fluid and gear box and differential fluid should be replaced with equivalent synthetics. Synthetics increase mileage by reducing the total friction on the vehicle's drive line. Reduced friction allows the 6.0 engine to work less to accelerate, coast and maintain speed.
If you have accumulated over 75,000 miles, consider replacing the spark plugs. Spark plug posts wear down from heat and combustion, extending the gap between electrode and grounds. Gaps exceeding recommendations result in less efficient combustion and increase fuel consumption.
Clean or replace fuel injectors. Deposits on fuel injectors result in poor spray patterns and incomplete combustion, robbing the engine of performance. Clean with a fuel system additive. Replacing the fuel injectors after 90,000 miles can result in fuel mileage gains.
Alter Driving Habits
Reduce the total vehicle weight. Removing excess weight prior to driving can result in significant mileage gains. According to the U.S. Department of Energy (DOE), mileage can be improved by up to 2 percent for every 100 pounds removed. Heavy toolboxes not needed for short commutes, extra seating and sandbags should be removed when not in use.
Drive less aggressively. The U.S. DOE determined aggressive driving can reduce fuel economy by 5 percent to 33 percent. Accelerate moderately, stay within speed limits, drive 55 mph on the highway and coast to stops (rather than maintaining acceleration and braking at the last minute) to improve mileage.
Turn the engine off when idling for extended periods of time. For every 30 to 60 seconds of idle, the 6.0L V-8 engine consumes enough gasoline to degrade total mileage per tank by approximately one-tenth of a gallon.
Operate the vehicle in two-wheel drive, when possible. If your vehicle is equipped with four-wheel drive, when engaged, the vehicle's engine must consume more gasoline to provide power to all four wheels when accelerating and maintaining speeds.
Performance Modifications and Tuning
Tune the engine and transmission with a performance hand-held tuning or software program. Professional tuners will access your vehicle's onboard computer (the PCM) through the OBDII port located under the steering column. Using specialized programs, a professional tuner will adjust fuel/air ratios, shift points, adjust fuel consumption at throttle settings and perform other optimizations for a specific fuel octane rating. Aftermarket hand-held tuners allow you to load preprogrammed (and custom) settings designed specifically for the 6.0L engine and your transmission combination (and can even account for aftermarket products, such as custom exhausts or cold air intakes). Performance tuners can improve mileage on the 6.0L engine by as much as 15 percent.
Install a cold air intake in place of the box air filter. A cold air intake blocks the engine heat from warming the intake. The result is colder (and more dense) air entering the engine, which allows more oxygen to enter the combustion process, improving the performance and power produced by the engine. Less combustion for more power results in mileage gains (if you can keep your foot off the gas).
Replace the stock exhaust system with an aftermarket performance exhaust. Increased exhaust performance will result in a balance between exhaust escape and back pressure, increasing the overall horsepower transferred to the wheels.
Insulate the exhaust manifold or headers with exhaust wrap. By constraining the heat to the exhaust system, less heat affects the air intake. As with a cold air intake system, colder and more dense air enters the combustion process, resulting in a more efficient engine.
Things You'll Need
- Fuel injector cleaner
- Fuel system cleaner
- Hand-held tuner
- Cold air intake kit
- Tire pressure gauge
- Compressed air
Skip Shelton has been writing since 2001, having authored and co-authored numerous articles for "Disclose Journal." He holds a Bachelor in Science in education and a Master of Business Administration with an emphasis in management from Northwest Nazarene University. Shelton also operates a small automotive maintenance and part-replacement shop.