The Hummer H2 SUT, known for its robust design and powerful presence, isn’t typically associated with fuel efficiency. For owners concerned about gas mileage, especially with the SUT (Sport Utility Truck) variant, understanding real-world MPG and potential improvements is crucial. This article delves into practical steps to enhance the fuel economy of a Hummer H2 SUT, drawing from actual owner experiences and proven modifications.
One Hummer H2 SUT owner in the Boston area, driving a 2005 model, shared their journey to improve MPG in city and highway conditions. Initially, with a stock truck and a Corsa Sport Cat Back Exhaust, they observed 10.2 mpg in the city and 16.1 mpg on the highway. Seeking better fuel economy, they implemented a series of upgrades focusing on efficiency and performance.
The first modifications targeted the transmission and engine lubrication systems. A Dorman extra capacity transmission pan, increasing fluid capacity by 2 quarts and filled with Royal Purple ATF, was installed. This was followed by an Airaid CAI (Cold Air Intake) with filter to improve air flow to the engine and switching to high mileage synthetic oil for reduced engine friction. Furthermore, Royal Purple lubricants were used for the front and rear differentials and transfer case, minimizing drivetrain friction. The owner also ensured their stock 35-inch BF Goodrich tires on 17-inch Mickey Thompson wheels were inflated to the correct PSI, a simple yet often overlooked factor in fuel economy.
The most significant improvement came from installing an intune i1000 Diablo Sport Performance Tune, optimized for 91/93 octane fuel. This tuner, easy to install and operate, recalibrated the engine’s parameters for enhanced performance and efficiency. Using 93 octane fuel readily available in Boston, the owner conducted MPG tests over three days, driving 25 miles each time. The results were notable: city MPG increased by 1.1 mpg to 11.3 mpg, and highway MPG saw a substantial jump of 3.7 mpg, reaching an impressive 19.8 mpg. These tests were consistently repeated to ensure accuracy.
While already achieving near 20 mpg on the highway, the owner further aimed for over 20 mpg by installing headers, hoping to further optimize exhaust flow and engine efficiency. Beyond fuel economy, a dyno test revealed performance gains of +28HP and +25FT/LBS of torque over stock, demonstrating that fuel efficiency improvements didn’t compromise, but rather enhanced, the vehicle’s performance. For Hummer H2 owners looking to improve their gas mileage, these real-world modifications offer a promising path to better fuel economy and enhanced driving experience.
