K & N Intakes & Air Filters: How to Breathe Easier and Save Fuel
by Steve Temple
Are you experiencing the following symptoms? You feel your stomach knot, your breathing constrict, your heart pound. That's a fairly typical condition the closer you get to your local gas station, especially when you spot the latest highway robbery taking place at the pump.
Okay, there's obviously some sort of virus going around, as so many folks report having the same affliction. But when your off-road passion is fed by fossil fuels, you feel even sicker. After all, the last time we checked there wasn't any public transportation to take you down Titus Canyon.
So, short of looking for a Prius lift kit (yeesh!), what to do? You've tried all those fuel-saving tricks like pulling up to the pump in the pre-dawn hours to get the first gulp of chilled, denser gas; you maintain 65 mph even with your foot twitching on the throttle. Now, maybe it's time to look at the efficiency of your engine. One of the first components that come to mind is your intake system. Just ask K&N.
Better airflow, less gunk in your engine, horsepower gains - that has to translate into maximum efficiency and improved fuel-savings. But as the old saying goes, your results may vary (depending on your vehicle and usage). Even though K&N can't provide a hard number, the company is known for product claims backed by thorough testing. What K&N can definitely establish are improvements in raw power: "We can test for air flow; we can put a vehicle on the dyno and prove horsepower increases," says Tim Stewart of K&N. It stands to reason that more power, used properly, will mean you save fuel too.
Fortunately, K&N customers have provided their own road testing on the testimonial section of the company website... After installation of a K&N Intake System, a Jeep Liberty went from 16 mpg (or 285 to 310 miles on a 20-gallon tank) to 18 mpg (330 to 350 miles per tank), a gas-savings of 2 mpg. A Subaru Forester gained 2.5 mpg with a K&N replacement filter. A Hyundai Tiburon's mileage went up by 5 mpg! And a diesel Jeep Liberty went from 24 mpg to 27 mpg on the highway. The testimonials keep rolling in - all realizing a minimum of 10 percent gas-saving gain, which should mean an extra day or so of driving before you have to face that highwayman at the gas pump.
The concept of K&N air filters is pretty simple. Turbulent air hits the pleated, multi-layered, oil impregnated surgical cotton filter surface. Contaminants are caught on the filter surface; the oil barrier holds the dirt, which acts as an additional filter medium without clogging the filter.
The key to improved airflow starts with the fact there are no "holes" in the filtration medium - just crisscrossed cotton fibers that hold the particles in suspension with the oil. The bonded mesh straightens the airflow and sends a high volume of clean, less turbulent air into the intake system. After 30,000 to 50,000 miles-sooner for off-road vehicles that live in dust-you clean the filter, pop it back in and off you go. K&N began developing air intakes systems in 1992-if stock replacement filters increased airflow. Just think how much better the performance increases would be with improvements to the air box and tubing. The best way to deal with the factory air box is to just remove it (since they're basically designed to reduce engine noise by restricting airflow). An air filter's ability to increase flow and filter out dirt is limited by the size of the air box - so out it goes.
In its place is a large conical open element filter. Now you've got just that much more filtration ability and huge increases in air flow.
K&N engineers next addressed the often twisted, narrowed path between the intake system and the carburetor or throttle body. They compare this restrictive breathing system to the effort it would take an athlete to run a marathon breathing through a snorkel, or worse yet, a soda straw. The solution is to eliminate the bends and tweaks in the tubing and use either molded high-density polyethylene or aluminum tubing to increase volume and eliminate the soda-straw effect.
Even if gas prices ever drop to something sane (or when pigs fly), or if our incomes increase to absorb the ever-rising cost of oil-based products (like when pigs start doing loopdy-loops), you've still got an air filter or intake system with all sorts of benefits. Such as dyno-proven performance, a million-mile warrantee and the ability to filter out all your off-road dust. That's not a complete cure, but it should help you endure those fossil-fuel symptoms that are now so common. Not to mention it can help to save gas too.