Installing A K&N Filter in a Caprice

Update - 2008

I no longer own the Caprice. My general conclusions after having the K&N installed for about two years is that it may be more of a hassle than it is worth. There may be performance gains, but nothing you're likely to notice in day-to-day driving. The problem is that the K&N lets fine filtering oil to be sucked through the intake. I doubt this is a huge problem for the engine, but it eventually coats the MAF (Mass Air Flow) sensor. The problem exhibited itself in my car as a nasty hesitation as the engine computer attempted to reset itself.

The MAF can be cleaned by removing the intake pipe and wiping the MAF very carefully with a Q-Tip and alcohol. This gets rid of the problem, but it will be back in a couple months.

Preamble

I'd been looking at one of these kits for some time. If you spend much time on the net reading about these cool cop cars, or their sexier cousins, the Impala SS, then you've probably run into the "first base delete" mods. This modification removes the large, empty rectangular piece of black plastic that connects from the air cleaner to the "home base," a large five-sided piece of black plastic that sits atop the engine. Some folks also remove the home base. The idea here is to cut down on air resistance to improve performance.

K&N makes Kit 57-3011 which not only replaces first base with a cool-looking black tube, but also completely replaces the air filter and filter box with a big unrestricted cone filter and black metal housing.

I bought mine from Auto Parts Warehouse. I have no affiliation with these folks, but they've been reliable, the shipping was prompt, and the prices seem fair.

For reference, my car is a 1995 Chevrolet Caprice 9C1 ex-highway patrol vehicle. It has a 5.7 liter LT1 engine.

The Installation

Step One: Remove old filter setup

removing old intake The first thing to do is perform an intake-ectomy. This removes the assembly of sound chamber (first base), mass air sensor (square metal part with one electrical connection) and old air cleaner box.

removing old intakePull the whole assembly apart to get at the meaty mass airflow sensor inside.

Step Two: Nipples

nipples in box Now the only thing left in the car is the bottom of the old air cleaner box. Keep reading for a tip on getting this part out.

more nipples Okay, see these two perky red little nipples in the photo? These are refered to as "lower tabs" and then "push clips" in the instructions. It is important to keep them intact, as you will need them in subsequent steps. You may be familiar with them, but these are not like any squeeze clip mechanism I've seen before.

I've made a drawing below showing the basic mechanics of disengaging one: how the nipples work To get these little buggers loose, squeeze the tops of them with pliers until you hear them pop. What you are trying to do is use the inward force of the pliers to push a plastic pin down and out of the top part of the clip. This will release bottom of the air cleaner box.

The plastic is resiliant, so you probably won't break the clips during normal use. However, if your car is like mine, someone may have broken yours, not understanding the principle. I had to reshape one of mine to more-or-less its original form. Don't worry, they don't need to work for the K&N kit to fit, but they do need to be there.

Intermission

cleaned out Now that everything's out, you'll be looking at the top of the car's metal computer housing and a (mostly) bare wheel well. The car is cleaned out. Cool. The only two things to keep track of under the hood are the mass air sensor electrical connection and the air injection hose.

I used some masking tape to make sure I didn't lose them.

Step Three: Box goes in!

kn kit parts You'll have assembled the new parts as per the instructions. I only ran into a couple things.

The new metal air cleaner box (labeled 1 in the photo) had a screw hole that I couldn't line up no matter how much I swore at it. The drill press cleared this problem up right away.

The mass air sensor (the square metal box you rescued before) fits into a big rubber donut called the "filter adapter" in the instructions. The filter adapter then fits into the big hole in the new air cleaner box. The instructions actually mention that "this is a very snug fit." They aren't kidding!

Here's how I ended up managing to do this:

  1. Stick the filter adapter about 1/4" into the air cleaner box hole
  2. Then insert the mass air sensor into the filter adapter
  3. Now brace a person against a wall and have them hold the box while you use a rag to push on the air sensor until the filter adapter is more or less flush against the cleaner box

a sexual installation actNote: you could substitute the person with a wooden contraption to resist at the right places. Also, depending on the size and strength of the people involved, you may need to do something on the floor as pictured in the illustration (note the position of the air cleaner box). I'm not kidding.

air cleaner box in Installation is the easy part. Put the air cleaner box over the push clips (remember those from Step 2?) and press down until it's in place. Nice. It is now probably the cleanest thing under the hood.

Step Four: Wrap it up!

bracket The metal bracket uses five different pieces of mounting hardware. The instructions are anything but clear as to which pieces to use where. In my illustration to the left, the short end of the bracket gets parts 3, 4, and 5. The long end gets 1 and 2. The parts are as follows:

  1. Round-headed hex screw (shorter)
  2. Internally threaded coupling nut
  3. Cylindrically-headed hex screw (longer)
  4. Blank cylindrical metal spacer
  5. Nut with nylon insert

attach tube Stick the tube into the intake's rubber "bellows," then over the mass air sensor. Secure with hose clamps.

air injection filter Oil up the little air injection filter as per the instructions. Wait 20 minutes. Then stick it in the box and connect the air injection hose to it. Tighten with hose clamp.

big filter in place Ah, now the finest moment. Stick the big air filter onto the rubber adapter and tighten with hose clamp. Connect mass air sensor electrical connection. Reconnect negative battery terminal. You're done!