• About FILTER
1How many kinds of materials are there for air filters?
There are two types.
There is nonwoven dry paper filters available in cotton and sponge.
The second type is dry or wet woven filters available in cotton or sponge. K&N uses woven cotton.
More K&N Information is here >> K&N Engineering Inc. FAQ
2What are dry type of air filter and wet type?
The difference is oil in material or not. As a rule of thumb factory vehicles use dry nonwoven fabric for their air filters. However, on some of sports cars like the Nissan R35GT-R, Honda S2000, and Integra Type-R use a wet nonwoven material.
More K&N Information is here >> K&N Engineering Inc. FAQ
3Dose wet filter hear the rumor that air mass sensor breaks down?
Reports were received stating the oil of the air filter adhered to the air mass sensor causing it to fail. These reports are false and untrue. K & N Engineering collected various broken air mass sensors from various countries, and conducted a third party inspection test. The results proved K & N filters do not to adversely affect the sensor. The most common causes of sensor failure are silicon grease, blow-by gas and return oil during sensor assembly. The MAF sensor was also shown to be was used without a filter, causing dust contamination that. K & N filters can be used reliably.
4Why does power rise when the air filter element is replaced?
Replacement filters allow fresh, clean ambient air allowing the engine to “breathe more” upon sudden acceleration, uphill and at high speeds. However, over time the filter will become clogged due to contaminants decreasing the volume of air entering the engine is limited by engine size and filter design. OEM applications incorporate quite a bit of sponge material decreasing that also inhibits the size of the filter, restricting air flow and decreasing overall life and performance of the factory filter.

Case of Sports cleaner
Sport cleaner type inhalation resistance is significantly reduced compared to normal. However, power is not increased just by reducing the inhalation resistance alone. The computer always corrects and learns the air-fuel ratio (A / F) and delivers the best A / F for general driving. The correction and learning values are then converted within the allowable perimeters, and CPU adjusts factory settings are made so the A / F value creating power. MAFs (air mass sensor), fitting adapters have been developed to match the sensor characteristics depending on vehicle make. Sport cleaners improve their power through various factors, the intake air temperature being the most important factor.
5How much durability is there?
K&N filters provide excellent durability with no sudden deterioration in performance or construction. Third party testing has shown K&N filters have been used on cars and trucks without maintenance for up to between 160,000 ~ 240,000 km. K &N filters come with a lifetime warranty. The savings from purchasing a K&N rechargeable filter saves the consumer valuable time and money from not having to constantly replace the factory air filters.
More K&N Information is here >> K&N Engineering Inc. FAQ
6Is there product warranty?
Yes. There is a 6 month guarantee period from the date of purchase. (Regular items in Japan, limited to purchase in case of)
7How is the filter maintained?
All K&N filters can be recharged (rewashed). The recharging intervals depend on driving environment and conditions. If the color the fades or starts becoming black, it is time for routine maintenance of the filter. Recommend maintenance is about every 3,000 -5,000 kms. Both sports cleaners and RAM AIR SYSTEM require the same maintenance schedule.
More K&N Information is here >> K&N Engineering Inc. FAQ