K&Ns Filtercharger Performance Kit includes the parts shown to replace your stock airbox and plenum. A nice surprise was the complete K&N Recharge Kit, including an air filter cleaner and oil (in the box) to keep the element serviced properly. The black, formed sheetmetal with the hole through it is the heat shield, which keeps the cooler incoming air isolated from underhood engine heat. |
Start by removing the factory plenum. Disconnect the crankcase vent hose, unhook the six airbox clips, and remove the nut from the throttle-body stud (yes, it does take a 3/4-inch wrench--whatever happened to using a wing nut?). The stock plenum can now be set aside. |
Use a 1/2-inch socket to unfasten the three bolts holding the airbox. There are nuts on the back side of these bolts (in the fenderwell), so you may need a helper (bribe your neighbor's seven-year-old child) to hold a wrench on the nuts to keep them from turning. As you lift out the airbox, unclip the axle vent hose from the side and reclamp or zip-tie the hose to a new location. |
To gain maximum airflow, use a utility knife to trim the rubber splash shield from behind the grille. We noticed that the intake for the K&N system is actually a couple inches higher than the factory setup for a slightly increased fording capability. |
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Attach the rubber isolator stand-offs to the K&N heat shield, and assemble the saddle and bracket (which will support the intake tube). |
Here's how the saddle and bracket are mounted to the heat shield. Notice that K&N includes a length of rubber weatherstripping that slides over the edge of the heat shield and seals against the vehicle's hood to keep engine heat away from the intake. Cool air is denser than the hot underhood stuff and since more air can carry more fuel you'll have more power. More is good. |
The completed heat shield can now be installed. Use two of the three original holes in the fenderwell. At this point, the heat shield will seem loose due to the flexibility of the rubber stand-offs. Don't worry. As other parts are attached, they will all tie together firmly, yet still allow for some engine/chassis movement. |
Coat the threads on the K&N-supplied stud with a dab of thread-lock compound and twist it into the throttle-body. Then slide the funnel-shaped stand-off over the stud--be careful not to drop anything down the throttle bores. |
The K&N intake tube can now be positioned by first inserting the round end through the heat shield. Use the factory throttle-body stud nut (unless you've decided to spring for an old-tech, honest-to-goodness, real steel wing nut) to snug the plenum to the stand-off. Also, a little smear of silicone applied to the throttle-body gasket will help seal out grungy air. |
Giant, night crawler-size, worm clamp no. 1 is used to hold the intake tube to the saddle. Don't forget to attach the crankcase vent hose to the nipple on the side of the tube (K&N has even provided a clamp for this). |
Finally, use giant worm clamp no. 2 to attach the K&N Filtercharger element to the intake tube, and you're done. The filter element comes preoiled by K&N, but we gave ours a second coat for extra protection on the dustiest of trails. |
More absorbent! Brighter whites! Now 50 percent bigger! Better tasting! We've all heard hard-sell ad jargon before and have, on occasion, even bought into the hype. Disappointment becomes your only purchase, though, when you discover that product and propaganda don't necessarily equate.
More horsepower! Twenty-six percent more airflow! More responsiveness! Again, nothing you haven’t heard before, right? The difference this time is that K&N’s Generation II Filtercharger Fuel-Injection Performance Kit actually delivers as advertised. And we’re not talking about a barely noticeable improvement--no measly couple hundredths of a second--our 1994 Grand Cherokee tester quickened its zero-60 elapsed time from 9.84 to 9.09 seconds, for a very noticeable 3/4-second gain.