Q: Do K&N air filters really work? Do they increase gas mileage or horsepower ?

Hi There, This is somewhat of a relative question depending on the type of vehicle (you did not specify) and what type of filter you are currently using. Most of today’s modern vehicles have computers with engine management systems that make adjustments to air/fuel mixtures constantly as the vehicle runs. Depending on the way the driver handles the vehicle and the way the motor is tuned, these filters may increase horsepower very minimally (~5hp or so) and may also increase fuel mileage slightly as well. The important thing to keep in mind, however is how the car is tuned and how the driver behaves in terms of driving habits.