AIR FILTER FOR BMW 3E21 M10B20 2.0L 4cyl 3 E21 M20B23 2.3L 6cyl 3 E21 KNECHT LX 252

The engine air filter acts as a consumable element that prevents dust, soot, small particles with air from entering the engine combustion chamber.

The filter element cleans the incoming air from harmful impurities, protects the motor from clogging. For complete combustion of fuel in an internal combustion engine, it is necessary that the air content in the combustible mixture is up to 20 times greater than that of fuel. Outside the car, the air contains dust particles, seeds of various plants, and so on, if these components get to the engine, they will begin to act as abrasive elements and accelerate engine wear. 

1. 3 (E21)
2. 3 Saloon (E21)
3. See more in applications

Additional purposes of the air filter

In addition to the main purpose - cleaning the air from dust of small particles, the KNECHT brand Air Filter of the drive performs the following functions:  

1. in engines running on gasoline, the filtering device acts as a regulator of the temperature of the combustible mixture;
2. muffler of noise;
3. provides ultimate resistance to intake air.

The principle of operation of the filtering device is as follows: the incoming air flow passes through the filter, small particles are retained by the filtering element, and the cleaned air enters the intake manifold.