My air filter cover has a hose that goes to the oil cover and people tell me to remove that because it's not really needed and could lose power because of the heat being taken in.So, my question is...Should I remove the hose that is connected to the Oil cover? or should I leave it connected?andIf I should be remove the hose that is connected to the oil cover, should I replace the air filter with a new cover?
this is the crankcase breather vent system, with the positive crankcase ventilation valve. most of the time the engine has vacuum, so the hose is pulling fresh air into the oil cover, and this air should be filtered. when your foot is on it hard there is no vacuum, there is blowby, so to keep the engine compartment cleaner the oily, warm blowby is sucked into the carb. most performance air filter assemblies lose the hose for simplicity, horsepower difference is insignificant.