In an era of fluctuating fuel prices, optimizing your vehicle’s efficiency has become a top priority for many drivers. While a complete bodywork overhaul might be impractical, minor aerodynamic adjustments can make a significant difference. Premier Aerodynamics, specialists in airflow analysis, have shed light on this topic by examining the effects of mud flaps on fuel consumption.
The team at Premier Aerodynamics employs OpenFOAM, an open-source computational fluid dynamics (CFD) program, to evaluate and demonstrate the aerodynamic performance of various vehicles. In their latest study, they focused on pickup trucks, specifically addressing the question: Do mud flaps affect your truck’s miles per gallon (mpg)?
Mud flaps and the Toyota Hilux: an aerodynamic study
To investigate the impact of mud flaps, Premier Aerodynamics conducted a simulation of an eighth-generation Toyota Hilux, a model recently being phased out. The simulation was run at a speed of 100 kph (62 mph) typical of highway driving. Although the Hilux is not sold in the United States, it serves as a relevant comparison for midsize pickups like the Toyota Tacoma.
The analysis revealed that mud flaps do generate additional aerodynamic drag. However, this effect is relatively minor compared to the drag caused by the Hilux’s tall ride height, which creates substantial wakes around the wheels. Mud flaps exacerbate this issue by disrupting airflow higher off the ground. Consequently, mud flaps increased the coefficient of drag from 0.37 to 0.38. According to the host of the explanatory video, removing mud flaps could potentially save $70 annually in fuel costs, assuming most driving is done at highway speeds.
Aerodynamic improvements for better fuel efficiency
While removing mud flaps can yield some improvements in mpg, other modifications might offer more substantial gains. The host suggests covering the truck bed, particularly with a fastback bed cover, or lowering the ride height. The eighth-generation Hilux’s pronounced wheel arches and sharply angled A-pillars were also criticized for their contribution to aerodynamic drag. These styling features, while visually appealing, do not serve a functional purpose.
It would be intriguing to see how the restyled ninth-generation Hilux compares in terms of aerodynamics. Despite its appearance, the simulated truck performed better than expected. The front end effectively keeps airflow attached, although it bleeds off behind the front wheels due to the ride height. The body line between the rear wheel well and tailgate slopes up to act like a diffuser, and the airflow over the bed is well-managed. This demonstrates that automakers sometimes prioritize aerodynamic efficiency in their designs.
