Modifying your intake to a K&N cone-style filter

Here's a quick run down of the cone intake procedure including how to remove the airbox. It's basically the installation instructions for the kit that Steve Calbert is providing. We just cut the portions that weren't needed. This upgrade can be done on any Grand Prix. It's one of the best bang-for-the-buck upgrades you can perform.

Begin:

There are several ways to upgrade your GP to use the cone-style intake. The following is one example.

Here are the parts you will need:

• K&N cone filter - a 7"-9" filter with a 4" outlet will work fine (I used P/N RE-0870 but any general cone filter may be used; the rest of the hardware below must match the size of your filter so pay attention to this!)
• Pipe - the type can vary depending on who is doing the modification but here are a few choices: a 5" long portion of a 45 degree bend of aluminum or stainless 4" piping, or a 3" PVC 45 degree elbow (or anything else that will work)
• 4"x3" rubber coupler - this will connect the pipe to the cone filter (or similar; make sure this fits both the throttle body, which needs a 3" rubber end, and the pipe, which is whatever diameter you selected)
• Rubber grommet - any will do but make sure it has a 1/2" ID (inside diameter); this is used to insert the Intake Air Temperature (IAT) sensor into the air stream (required by the PCM to detect air flow and select air/fuel ratios)

This does not address the new location for the PCM. Many have strapped it to the overflow bottle, or have made a bracket that uses the factory mounting location. Drawings in .dwf format (a set of three files zipped up) are available for the bracket assembly for those of you who have access to a metal fabrication shop.

Tools Required:

• Ratchet set
• Phillips screwdriver
• Flat-head screwdriver

The Upgrade:

Begin by removing the three bolts holding the metal cross-brace over the airbox. With these bolts removed, the brace comes off easily and you will have full access to the airbox.

Remove the lid from the airbox by releasing the clamp that is on the side facing the firewall. Remove the cover. Inside you will see the PCM (it looks like a metal box and has two large electrical connectors on one side). There is a rubber grommet where the wires for the PCM enter the airbox. Just slide it up and out of the channel it sits in. You can now lift the PCM out of the airbox and sit it to the side without putting any stress on the connectors (there is no need to disconnect the wiring).

Before we forget, take the IAT (Intake Air Temperature sensor) sensor out of the intake piping. It lies just before the throttle body with two wires running into the quick connector for the sensor. Simply unclip the connector, pull the sensor out, and move the wire to the side. Set it aside, but be careful not to lose it. Your GP needs this to function properly!

Release the latches that are holding the side cover (closest to the engine) off of the airbox. Remove the stock filter and notice that it is dirty in a particular area (which shows that it was hardly using the entire area for cleaning the air).

Next, you will remove the intake plumbing from the throttle body. It is just sitting on there, but will require some effort to remove. Just pull and twist on it until it pops off. Once removed set it off to the side (it will not be used again, but you should probably keep it around).

Now, in the bottom of the airbox there are three bolts that hold the box to the frame. Remove these bolts and store them for safe keeping should you want/need to put your stock setup back on the car. Remove the airbox itself. You may notice some crud in the bottom of the airbox, which is some of what had entered it in stock form.

This next step is optional. The plastic plate on the fenderwell that the "snorkel" from the airbox fit through can be easily removed and allows a lot more fresh air to enter the engine compartment. I have been driving without it on for a while and the filter has been fine (it has never gotten wet).

Drill the appropriate size hole in the pipe and install the grommet you bought. Insert the IAT sensor into the grommet. Attach the pipe to the coupling.

Take the coupling/pipe combination and put a light layer of motor oil on the inside lip in the exposed end of the coupling. This will help it go on the throttle body more easily. Slide it on the throttle body but do not clamp it down just yet.

Take the filter out of the box and slip it onto the end of the pipe. Tighten down the band strap on the pipe. Now, turn the coupling on the throttle body so that the filter is aligned adequately as to not contact any other engine surfaces.

Clip the electrical connector on to the IAT sensor.

Re-install the cross brace to the frame that was removed in the first step. Make sure it is snug before driving anywhere (I advise starting all the screws first and then tightening them each down later).

That's it, you're done. Now just crank it up (and listen to the supercharger turn, for those GTP owners). If you have a GT you will probably hear more induction sounds than you did before.

The last thing to do is take it for a spin. You will notice that it seems to go to the redline much easier and has a great sound while doing it. Time to track down a few unsuspecting vehicles!

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