Range helps fuel economy in two ways. First, it enhances factory Active Fuel Management (AFM) on your vehicle to ensure that your truck or SUV spends more time in 4 cylinder mode than 8 cylinders. Second, it teaches you how to drive for fuel economy in any vehicle. Here are the 3 key tenets:
Fuel economy begins with "Load"
Fuel economy is 100% dependent on the load that you put on your engine. If you think about how to ease the load on the engine, the most common fuel saving tips seem obvious. Removing unnecessary items from your vehicle, maintaining adequate tire pressure (to minimize rolling resistance) and reducing idle time all help improve economy. Range can only switch the vehicle to 4 cylinder mode in low-load situations. As such, you can not only save fuel by reducing load, but also by allowing Range to use less cylinders. Low load is key to big fuel economy gains with Range - up to 12-14%.
Roll on to the throttle
Rapid acceleration is the enemy of efficiency. Factory AFM is very sensitive to throttle. Range reduces this sensitivity, but thinking about throttle is important. In order to maximize fuel economy, find the level of throttle that allows your vehicle to speed up on a level road in 4 cylinder mode and try to replicate that. While it may require twice as much time to get up to speed, the overall increase in trip time is negligible. According to the NHTSA, gradual throttle saves 3-5% in fuel economy and only results in 4 minutes of added average commute time.
Speed up to maintain
Again, the key to remaining in 4 cylinder mode as long as possible is eliminating high load scenarios. High load occurs when the vehicle is using more power to do the same amount of work, such as going uphill or accelerating rapidly. When driving, I'll often try to speed up early to avoid using the throttle to climb a hill, or achieve speed. In this way - I can apply steady throttle over a long period rather than increasing throttle quickly. Sometimes its possible to stay in 4 cylinder mode the whole time and sometimes it isn't, but regardless it is a far more efficient way to drive.