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Miata Header

Your Miata

Pick your year to see what fits.

There was no 1998 Miata in the US. The NB model started as a 1999.

+4–8 whp (est.)
Hard$455–$6153–4 hrs
All Miata mods

Why do it

A freer-flowing header replaces the restrictive stock manifold and adds power up top.

Heads up

Some headers aren't CARB approved and can't be shipped to California. Check your state's rules.

Tools you'll need

Starting out? See our budget tool list.

Parts to buy

Double-check fitment before buying. We may earn a commission when you buy through these links, at no extra cost to you.

Before you start

  • Soak every exhaust nut in penetrating oil the night before.
  • Removing the primary cat isn't street legal everywhere and can trigger a check-engine light. Check your local laws first.
  • Soak every exhaust nut in penetrating oil the night before.

Steps

  1. Remove the heat shield

    • Take off the heat shield and its hardware.
    Watch this step (CashedOutCars, on a Miata) (0:49–2:13)

  2. Disconnect the exhaust

    • Unplug the O2 sensor wire and undo the exhaust below the header.
    Watch this step (2:13–4:45)

  3. Remove the old header

    • Work the old header out and scrape the old gasket off the head.
    Watch this step (4:45–6:55) Watch the cleanup (6:55–8:18)

  4. Fit the new header

    • Fit the studs and new gasket, drop in the header and tighten everything.
    Watch this step (8:18–10:48) Watch it tighten down (10:48–11:24)

  5. Reconnect

    • Reconnect the exhaust and O2 sensor, then start it and listen for leaks.
    Watch this step (11:24–13:14)

  6. Remove the old header

    • Take off the heat shield, disconnect the O2 sensors and work the stock manifold out.
    Watch this step (Flywheel Films, Racing Beat on an NC) (3:48–11:29)

  7. Install the new header

    • Fit the gasket and header, then reconnect the O2 sensors and exhaust.
    Watch this step (11:29–17:15)

How to know it worked

Did this guide work for you?

Safety first

  • Park on flat ground, set the parking brake and chock the wheels.
  • Never get under a car held up only by a jack. Use jack stands.
  • Let the engine and exhaust cool first.
  • Disconnect the battery before unplugging electrical parts.
  • Wear safety glasses.
  • If something doesn't match your car, stop and ask a shop.

Follow your part's instructions and your service manual's torque specs.