ZJ K&N Fuel Injection Performance Kit Install
	Category:	Performance
	Author:	Eric
	Date:	March 16th, 2004

A very common upgrade, any auto enthusiast looks for is a K&N performance air cleaner. The stock air cleaner in most vehicles today are located inside a box that has a small inlet and then travels down a corrugated tube and into the throttle body. You can buy a K&N filter that will fit into your stock air box which allows for more air flow than the regular paper filters. However this option only gives you minimal performanc gains. The best route, however, is to get the K&N fuel injection performance kit (FIPK).

Stock Intake.

The FIPK replaces everything including the air box, flat paper filter and intake tube. The stock intake tube is replaced by a smooth and large diameter tube allowing for greater flow. On the end of this larger tube is a new cone shaped filter. The filter has a greater surface area allowing for greater filtering and air flow. On most versions, including this one for a Grand Cherokee, the air box is replaced with a heat shield. What this does is prevent the hot air from the engine getting to the filter. It catches cold air from the front of the vehicle through the grille. All in all, this setup will flow more cold air into the engine which is turned into more horsepower and better fuel economy.

The installation is very strait forward and only takes about 30 mins. You have to remove the old air box and intake tube which was held on with only a hand full of bolts. For my application, there was a thin rubber sheet blocking the air passage from the grill to the air filter so that was cut out. On the throttle body, there was some peculiar mounting hardware that was replaced with a single threaded stud to mount the new tube. The new hardware used the same holes as the stock hardware making the whole installation a piece of cake.

Removing the stock airbox.

The rubber sheet that blocks air flow through the grille.

After the sheet is removed, fresh air can flow through the grille.

The stock mounting hardware blocks the butterflys.

You see just how much larger and less restrictive the new intake tube is

It takes a few days for the computer to adjust to the new filter. I chose to disconnect the battery to reset the computer which should speed up this adjustment. The first thing I noticed was how great the engine sounded. With an air box, the sound your engine makes is muffled. Now you should be able to hear it much more under full throttle. As far as horsepower, I can definitely feel the difference in throttle response. Off the line and during passing is when it really shines. Just a FYI about the fuel economy: if you are driving your vehicle harder now because of the extra power, you will negate the better economy. Only if you drive normally will you see a gas mileage gain. I saw about 1 mpg.

The complete installation with heat sheild.

For ordering information, check out their website, KandN.com.