The AEM Bypass Valve is used to protect the engine from hydro locking. Hydro locking occurs when the end of the inlet pipe is submerged in water and the water is sucked into the engine. Driving the vehicle in rainy conditions is not enough to cause a problem unless the vehicle becomes submerged enough that the inlet end of the pipe is immersed in water. Rain impingement on the filter will not cause a hydro lock condition. The distance of the filter from the road dictates the level of water that can cause damage. This distance varies with the vehicle ride height which is why there are no published numbers for this measurement. All AEM Cold Air Intakes are to be used with the splash shield that is originally installed on the vehicle for protection and performance. The removal of splash shields actually deteriorates performance by allowing hot pavement air in the vicinity of the filter and negates any positive pressure created in the air filter area when the vehicle is in motion. There are some instances where there is not enough room around the inlet pipe for adequate clearance of the Bypass Valve. In these cases a Short Ram system is offered or will be offered in the near future..