During off-road with muddy conditions, the Fuel Pump needs to have higher dust-proof and water-proof capacity. According to the 2023 test results of the Society of Automotive Engineers (SAE), the failure rate of fuel pumps with IP67 or higher protection levels in mud environments with over 15 g/m³ sand content is only 2.5%, while that of ordinary pumps is as high as 34%. For example, Walbro GSL series fuel pumps have a stainless steel filter screen and sealed motor type. They can operate continuously for 500 hours in the condition where the water depth is 1 meter and the mud concentration is 30%. They provide a stable flow rate of 255 L/h (liters per hour), and the pressure fluctuation range is ±0.3 bar. It was given the title of Best Fit Product in 2022 by the owner of the Jeep Wrangler Rubicon by the North American Off-road Association (NWA).
The rust-resistant material is the defining feature of the mud Fuel Pump. A 2024 research article published in the “Off-road Engineering” journal suggests that a 316L stainless steel casing fuel pump with a polytetrafluoroethylene coating could last as long as 4,000 hours in an acidic muddy water environment where pH is between 4.5 and 8.5, which is 60% longer than standard aluminum pumps. AEM’s 320LPH high-pressure fuel pump has been the preference of the 2023 Baja 1000 rally winner team Red Bull Off-Road because it is MIL-STD-810G military standard certified (salt spray resistance test of 1000 hours). Its titanium alloy impeller can still have a flow error rate of less than 1.8% at a 5000 rpm rotation speed, allowing the racing car to shorten the fuel replenishment time to 90 minutes on the Mexican desert’s muddy roads, improving efficiency by 23% compared to the previous generation model.
The dynamic control ability of pressure and flow has a direct influence on the passability of the muddy ground. Bosch Motorsport’s 044 fuel pump features a variable voltage controller (operating voltage: 6-18V) capable of maintaining a flow rate of 300-600 L/h and a pressure of 4-7 bar when the load changes suddenly, and climbing on a 35° slope and instantaneous sinking conditions of automobiles. At the 2022 Safari Cross-country Race in Australia, after the installation of this pump in the modified Toyota Hilux vehicle, engine power loss was reduced by 14%, the likelihood of clogging by mud was reduced from 22% to 4%, and one repair cost was saved by approximately 1,200 US dollars. Industry estimates put the cost of acquiring fuel pumps specifically engineered for muddy ground as accounting for approximately 8% to 12% of the cost of modifying a vehicle, but can increase the level of race completion by 19 percentage points.
Maintenance costs are as crucial as cleanability designs. Fuel pumps with module quick-disassembly configurations (such as DeatschWerks DW300C) according to Frost & Sullivan can reduce cleaning time from 45 minutes for traditional pumps to 10 minutes, and reduce the cost of filter screen replacement by 65%. During the 2023 African Eco Rally, through the application of this design, the Land Rover Defender team reduced the maintenance frequency of the fuel system from every 500 kilometers to every 1,500 kilometers. The cost of maintenance decreased by 28%, and at the same time, the possibility of race time penalty due to downtime was reduced (average penalty: 15 minutes per occurrence).
Intelligent monitoring is becoming a new fashion. In 2024, Holley launched the HydraMat intelligent fuel pump, which is equipped with a particulate matter sensor (with ±5 μm detection accuracy) and a flow self-compensation algorithm. It can dynamically adjust the amount of fuel supply in real time (with a response time of 0.05 seconds), with a fuel delivery error rate of less than 0.5% even when the density of the mud is as high as 1.2 g/cm³. The Red Bull team verified in experiments in the Atlas Mountains in Morocco that this technology made the fuel economy of the car drop by only 3% during non-stop 8-hour driving on off-road areas muddy in nature, while efficiency loss in traditional pumps totaled 18%. Market estimations state that by 2027, the adoption of smart mud fuel pumps will have increased from 9% in 2023 to 37%, driving the size of the global off-road modification market to exceed 5.2 billion US dollars.