Why is the BMW's wading depth so low?
2 Answers
What affects a car stalling after wading through water are the air intake and exhaust ports. As long as the exhaust port has sufficient pressure to expel water from the intake port, the car can generally pass through the water surface without the intake port taking in water. The air intake of ordinary cars is located above the filter screen, while BMW's is below the filter screen, resulting in a relatively lower wading depth. Here are some relevant details: 1. General sedan wading depth: The typical wading depth for sedans is 20-30 cm because the exhaust port of ordinary cars is about 20-30 cm from the ground. The method to determine wading depth is to observe the height of the exhaust port. 2. Wading capability: Some car bodies may appear tall, but upon opening the hood, the air intake is positioned quite low. For example, models equipped with turbocharged engines usually have lower air intakes, primarily to enhance cooling, which makes their wading capability weaker.
As an enthusiast who frequently studies German car designs, I've found that BMW's conservative wading depth is primarily due to three factors: the low-slung sporty chassis reduces the intake height—just look at the M series with less than 12cm ground clearance; complex electronic systems concentrated beneath the chassis, especially the rear axle air suspension compressor which is highly vulnerable to water damage; and the exhaust tip design prioritizes aesthetics, making it prone to water backflow during heavy rain. I once drove a friend's X5 through a deep puddle in the rain—water just above the wheel hub center triggered fault codes. Later disassembly revealed the intake piping was about 8cm lower than same-sized SUVs, a design that demands extra caution in urban flood conditions.
