Home › BMW 3 Series E46 › Cold air intake

E46 · Power

E46 Cold air intake

Your E46

Pick your year so we only show parts that fit your car.

In the US, 1999 E46s were sedans only, and 2006 E46s were coupes and convertibles only. M3s aren't covered yet.

+5–10 whp (est.)
Easy$300–$4001 hr
All E46 mods

Why do it

A small power gain with a nicer intake sound. The K&N kits reuse the factory fresh-air duct and are street legal in all 50 states.

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

  • Get the right kit: K&N 57-1002 for 2.5L and 2.8L engines (323, 325, 328) or 57-1001 for 3.0L (330).
  • Both kits are 50-state legal. Keep the CARB sticker under the hood for inspections.
  • Keep the black plastic inlet duct that runs from the grille to the stock airbox. The K&N kit reuses it.

Video guide

How to install a K&N cold air intake on an E46 330Ci
by up2gio on YouTube

Same K&N intake style we list. The 2.5L and 2.8L kit installs the same way. Each ▶ button below jumps to that step in the video.

Watch the whole video

Steps

  1. Remove the stock airbox

    • Remove the two 10mm bolts holding the airbox down.
    • Unplug the wiring connector on the back of the box and the airflow (MAF) sensor's plug, loosen the clamp on the rubber boot, and lift the box out.
    Watch this step (0:19–1:25)

  2. Remove the intake boot

    • Unplug the small vent hose on top of the rubber intake boot, then loosen the clamp at the throttle end and pull the boot off.
    • Save the plastic inlet duct from the grille side. You'll need it.
    Watch this step (1:25–2:12)

  3. Fit the new intake tube

    • Press the supplied rubber grommet into the hole in the new K&N tube, then plug the vent hose into it.
    • Clamp the new tube onto the throttle body using the stock clamp.
    Watch this step (2:12–2:46)

  4. Prepare the heat shield

    • Press the rubber edge trim along the edges of the heat shield. Trim small notches with scissors to get it around tight corners.
    • Fit the stock inlet duct into the opening on the heat shield.
    Watch this step (2:46–3:53)

  5. Move the MAF sensor over

    • Release the two metal clips and take the MAF sensor out of the old airbox.
    • Slide it into the new rubber coupler with the same side facing the engine as before, and tighten the clamps snug. Don't over-tighten. The MAF housing is plastic and can crack.
    Watch this step (3:53–4:58)

  6. Mount everything

    • Set the heat shield onto its mounting studs and tighten the 10mm nuts, then join the MAF and tube and tighten the clamp.
    • Fit the support bracket with the hardware in your kit. Check that no pipe touches the hood, radiator or wiring.

    Tip: The person in the video couldn't get one bracket bolt to hold and improvised. If your kit's hardware doesn't fit, contact the seller for the right part rather than leaving it loose.

    Watch this step (4:58–7:04)

  7. Plug in and test

    • Reconnect the MAF sensor plug, start the engine and let it idle a few minutes.
    • Check for a check-engine light or a whistling sound (an air leak at a clamp).
    Watch this step (7:04–7:34)

How to know it worked

Did this guide work for you?

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.