Home › BMW 3 Series E46 › Cat-back exhaust

E46 · Sound

E46 Cat-back exhaust

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.

+3–8 whp (est.)
Medium$1,000–$1,5002–3 hrs
All E46 mods

Why do it

A deeper, sportier inline-6 sound and less weight. Gains are modest, so pick it mainly for sound.

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

  • Pick the right system for your model: the 330 and 323/328 kits bolt on; the 325 kit is cut & clamp.
  • The exhaust must be completely cold. Raise the car high enough to slide the exhaust out and support it on jack stands at all four corners.
  • Soak every exhaust nut with penetrating oil, ideally the night before. Old E46 nuts are often rusted.
  • A helper makes this much easier. The full system is long and awkward.

Video guide

Installing a MagnaFlow exhaust on an E46 330Ci
by Performance On Wheels on YouTube

The same bolt-on MagnaFlow system we list for the 330, on a 2004 330Ci. Skip the first 1:50 (cold starts of other cars). Each ▶ button below jumps to that step in the video.

Watch the whole video

Steps

  1. Unbolt the joint behind the cats

    • Find where the exhaust joins behind the catalytic converters and remove the nuts. Keep the hardware in case you need it.
    Watch this step (2:37–3:12)

  2. Release the hangers and lower the old exhaust

    • Remove the bolts holding the exhaust's support brackets to the car. Some people unbolt the whole rear bracket instead of fighting the rubber mounts.
    • Lower the old system with your helper.
    Watch this step (2:54–3:59)

  3. Assemble and hang the new system

    • Move the rubber hangers or grommets from the old system to the new one.
    • Put the clamps on loosely, lift the system into place with your helper, fit the front joint and the hangers. Leave everything loose for now.

    Tip: 325 (cut & clamp) kits: before this step, measure and mark the cut point on the stock pipe exactly as MagnaFlow's instructions show, cut it straight, and file off the burrs. If you're not comfortable cutting, any muffler shop can make the cut quickly.

    Watch this step (4:35–5:39)

  4. Line it up, then tighten

    • Adjust the pipes until the tips sit centered in the bumper and nothing touches the body or heat shields.
    • Tighten the clamps and bolts evenly to MagnaFlow's spec, front to back.

    Tip: If two sections won't slide together, squeeze the end of the inner pipe gently with a clamp. The video shows this trick.

    Watch this step (5:39–6:27)

  5. Check for leaks

    • Lower the car, start it and listen at each joint for ticking or puffing.
    • After a short drive, recheck that the tips don't touch the bumper and the clamps are still tight.
    Watch this step (6:27–7:16)

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.