450 smart fortwo (1998-2007) and 452 smart roadster standard air filter.
Clean intake air is essential to ensure the efficient operation of the engine and to prevent premature engine wear. Any abrasive particles of dirt, grit, salt and soot entering the engine will mix with the engine oil forming a 'grinding paste' which will rapidly cause expensive damage to engine friction surfaces. The only means of preventing the ingress of harmful contaminants is through the use of efficient and reliable air filters.
The air filter should also ensure that the engine receives a sufficient volume of clean air to efficiently maintain the correct air/fuel ratio, while providing an exceptionally high level of protection. An insufficient volume of air will cause symptoms of ineffective combustion such as increased fuel consumption and performance loss.
Electronic components, such as the highly delicate 'hot wire' or 'air mass' sensors located between the air filter and the combustion chamber also require a high degree of protection in order for them to transmit accurate data to the engine management system. Impaired operation due to damage caused by high velocity contaminants can result in expensive consequences.