K&N are probably the world’s most famous manufacturer of performance air filters.
K&N manufacturer a range of air filters to suit all conditions. From professional race teams on the NASCAR circuit to the car enthusiast who simply wants a standard replacement filter that he does not need to change.
Air filters are made in 3 main materials, paper, cotton and foam. Paper is the material chosen as original equipment as it is cheap to manufacturer and is a service part which needs to be changed. Paper offers good filtration and good flow but blocks easily.
Foam air filters use a variety of layers of different density foam to get the required filtration levels. Foam lasts for the life of the vehicle. Foam filters can be used with or without an additive depending on the model and manufacturer.
Cotton filters use a single type of cotton with a filter additive, oil in the case of K&N. The additive allows cotton filters to offer extreme levels of filtration and high levels of air flow.
K&N entry level filters are their panel filters. These panel filters are a straight swap for the original air filter and are as easy to change as replacing the original paper filter.
Performance gains? Revs magazine did a test years ago comparing performance panel filters against the original paper filter. They found that a new paper filter out flowed all the other filters in the test but blocked much more quickly leading to increasing losses in power in comparison to the other panel filters as the test went on.
In short, a new paper filter is the best for power, as long as you are prepared to change it regularly. If you are looking for filter which will maintain air flow after extended periods then an aftermarket panel filter is the way to go. In the long run they are cheaper that buying new paper filters and will give you more power more of the time.
The next step up in K&N’s range of air filters are their 57i kits. K&N 57i induction kits replace the standard air box with the cone filter. Some kits also come with heat shielding. These kits give the engine sound more character (ideal for drivers who want more sound form the engine but do not want a loud exhaust) and usually better throttle response. Again these filters will last for the life of the car if looked after.
The next step is the K&N FIPK kits. Similar to the 57i induction kits but they come with heat shielding and in some case replace more of the standard intake pipework.
The top of the range K&N filters are their Typhoon Intake Systems. These filters come in a variety of forms, from short rams systems which keep the filter in the original position to intake systems which relocate the air filter.
K&N Typhoon systems are available in a variety of colours and K&N have also included dyno figures for the systems they have tested.
In summary, K&N’s website is second to none in the industry. It includes a variety of photos of each individual product and well as packaging sizes and weights.
The instructions that come with K&N filters are also second to none, not only do they include a detailed list of all the parts that should be in the kit, the instructions also included detailed step by step photos making installation straightforward in most cases.