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RX-8 Cold air intake

Your RX-8

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+3–6 whp (est.)
Medium$350–$5001.5–2 hrs
All RX-8 mods

Why do it

Cheap and easy. The power gain is small on its own, but it sounds great and pairs well with a tune later.

Tools you'll need

Parts to buy

Always double-check fitment for your exact year, trim and transmission before buying. Prices change. ModBuddy doesn't earn money from these links.

Before you start

  • On the RX-8, the popular AEM 21-485 intake routes the filter low in the front of the car, so the front bumper has to come off. Plan for about 90 minutes.
  • The AEM kit is CARB exempt (E.O. D-670-21). Keep the sticker visible under the hood for inspections.
  • AEM says this setup is for mild weather and not deep water, since the filter sits low.

Video guide

Project RX-8: AEM cold air intake install
by The Slip Angle on YouTube

Same AEM intake we list. The teardown (bumper, bumper support, stock airbox) is a time-lapse, so pause it to see where things are. His kit was a knock-off and one bracket didn't line up; a genuine AEM kit fits properly. Each ▶ button below jumps to that step in the video.

Watch the whole video

Steps

  1. Prep the car

    • Let the engine cool, set the parking brake and disconnect the battery.
    • Raise the front onto jack stands and remove both front wheels. Bag and label every clip and bolt you remove.
    Watch this step (1:17–2:05)

  2. Remove the stock intake

    • Remove the engine cover and the strut tower brace nuts so you have room.
    • Disconnect the breather hoses at the throttle body (remember where each one goes), loosen the clamps, and remove the resonator and inlet tube.
    • Unplug the airflow (MAF) sensor and lift out the airbox. Unplug and cap the secondary air inlet as your kit's instructions describe.
    Watch this step (2:05–6:36)

  3. Remove the bumper

    • Remove the fender liner clips and screws on both sides, unplug the corner lamps, and remove the lower liner.
    • Remove the bumper bolts and set the bumper aside on something soft.

    Tip: Have a helper hold one side of the bumper while you pull it off so the corners don't scratch the fenders.

    Watch this step (2:05–6:36)

  4. Remove the bumper support

    • The bumper support is the metal bar you see once the plastic bumper cover is off. It runs across the front of the car and bolts to the ends of the frame rails on each side.
    • Unplug and unclip any sensors and wiring attached to it, and move them out of the way gently. Don't let a sensor hang by its wire.
    • Remove the bolts holding it on at each side and lift it off. Watch the video clip for this step to see exactly where they are.
    Watch this step (2:05–6:36)

  5. Build the new intake

    • Fit the MAF sensor into the new upper pipe, with the airflow direction pointing toward the engine. Reattach the breather hoses.
    • Connect the pipes and couplers loosely, install the lower pipe and its mounts, and fit the filter and prefilter. Don't fully tighten anything yet.
    Watch this step (6:36–9:02)

  6. Align, then tighten

    • Position every pipe so it doesn't touch the body, radiator or hood, then tighten all clamps and mounts.
    Watch this step (6:36–9:02)

  7. Reassemble

    • Reinstall the bumper support, bumper, corner lamps, fender liners and splash guard. AEM warns that leaving off the liners can let water reach the filter.
    • Reinstall the wheels and torque the nuts to spec. Reconnect the temperature sensor and battery.
    Watch this step (9:02–12:41)

  8. Test

    • Start the engine and let it idle for a few minutes, then check for any loose connections or a check-engine light.

How to know it worked

Safety first

  • Park on flat, solid ground, set the parking brake and chock the wheels.
  • Use jack stands rated for your car. Never get under a car held up only by a jack.
  • Let the engine and exhaust cool completely before touching them.
  • Disconnect the negative battery terminal before unplugging sensors or electrical parts.
  • Wear safety glasses, and gloves around sharp heat shields and hot fluids.
  • Tighten bolts to the torque spec in your factory service manual.
  • If a step doesn't match your car or you're unsure, stop and ask a shop.

These are overview steps written to help you plan the job. Always follow the instructions that come with your part and the procedures and torque specs in your factory service manual. Horsepower is an estimate; results vary.