Sizes of Car Air Filters

Car air filter sizes have different specifications. The FRAM PPA4309 measures 11.9 x 8.1 x 2.1 inches. Other models are a bit smaller, measuring 9 x 5.1 x 1 inches. There are other sizes that are available.


All automobiles have filters so the engine can function properly. Although their sizes differ, their main objective is the same. It is to filter the air outside before it enters the automobile’s engine. Filtering the air is necessary before it is burned with the fuel. Fuel and filtered air will be required for combustion.

Engine Protection

Unfiltered air can contaminate the engine. In the worst case scenario, it will damage the engine. The damage may not be immediately noticeable. Over time however, contaminated air lowers the engine’s efficiency. No matter what the car air filter sizes are, they are designed to prevent further damage.

Protect the Fuel System or Carburetor

The fuel injection system or carburetor injects the air and gas in the cylinders of the engine. This is known as the air/fuel mixture. Fuel injection and carburetor systems employ small valves and portals to do their work.

If debris or contaminated particles pass through these holes, the result is severe malfunction or permanent damage. The filter guards those delicate sections by filtering the air before it proceeds into the system.

Improving Fuel Economy

The filter has to be clean and properly installed for it to work. The filter will also improve gas mileage and performance. By sifting the air before it gets in the engine, entry of contaminants is minimized. Clean air leads to faster ignition. This leads to efficient combustion and boosts fuel economy.

When the air goes through the engine, it goes in the filter prior to reaching the fuel injection or carburetor. The filter keeps the air flow adequate, which boosts the system’s performance.


Majority of filters are composed of pleated paper. This is folded to an accordion like shape. It is set on a metal or plastic frame. This is designed to fit in precise filter holders in cars. Some filters are composed of polyurethane foam or oiled cotton. The filter holder is made up of a metal circular or plastic box.

Whatever the car air filter sizes you use, replace it when dirt has built up. This will lead to emissions system problems and lower gas mileage. For this reason, the filter has to be examined regularly.

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