R Rawr New member Jul 26, 2009 #1 I have heard that K&N air filters improve both HP and gas mileage. If so, what would a K&N air filter do to a 1999 Honda civic ex? How much horsepower and how much mpg would increase?
I have heard that K&N air filters improve both HP and gas mileage. If so, what would a K&N air filter do to a 1999 Honda civic ex? How much horsepower and how much mpg would increase?
