DIY Throttle Body Swap for 3.0L V6 Mazda6
Cordova Motorsports.com     Update: April, 2023

Web document at: http://cordovamotorsports.com/docs/DIY37kit.html
Original document at: http://cordovamotorsports.com/docs/DIY37kit-orig.html

This document describes the steps needed to perform a DIY swap over from a Mazda6 3.0L throttle body to a larger 3.7L throttle body using the parts supplied in the CordovaMotorsports DIY kit. The new DIY Conversion kit now includes a fully operational and optimized 3.7L Mazda throttle body. Please follow the below instructions carefully to prepare and install the larger throttle body on your 3.0L engine:
Customer parts Needed:
  • Working Cold Air Intake.
  • A T20 sized star driver.
  • Socket wrench & 10mm socket.
Cordova Motorsports Parts:
  • Optimized 3.7L throttle body.
  • Tapered throttle body adapter.
  • Extended bolts and washers.
  • Nylon coolant hose coupling & clamps.


Throttle body adapter on the 3.7L TB.

Included Parts in DIY TB Kit. Note: Image update pending
Step by Step instructions for changing over to the larger throttle body:
  1. Open the hood and allow the engine to cool for at least 1 hour.
  2. Remove the engine cover.
  3. Unplug the MAF sensor and remove the CAI intake hose from the 3.0L throttle body.
  4. Push the release tabs and unplug the throttle body wire harness.
  5. Remove the 4 10mm bolts holding the 3.0L throttle body to the manifold.
  6. Remove or cut the coolant lines that are attached to the 3.0L throttle body.
  7. Remove the 3.0L throttle body from the manifold and set aside.
  8. Use the nylon barb and small hose clamps to join the 2 coolant hoses together.
  9. Loosen the battery hold-down bracket so that the battery position can be adjusted.
  10. Detach the throttle body wire harness from the harness tie down near the manifold. This will create some extra slack in the wiring harness needed to reach the plug position on the new 3.7L throttle body.
  11. Attach the 3.7L throttle body and tapered spacer to the manifold using the provided extended bolts:
    • Push the battery back and to the right to provide extra clearance for the 3.7L TB.
    • Use a light coating of gasket sealer on both sides of the TB adapter.
    • Orient the small side of the taper against the 3.0L manifold.
    • The throttle body will be oriented with the TPS sensor facing the front of the car.
    • The spacer will be oriented with the angled edges facing up. (See below picture.)
    • Do not overtighted the bolts! 4-5 Ft./Lbs only.
  12. Plug the TB wire harness connector onto the throttle body.
  13. Reconnect the CAI coupling onto the 3.7L TB and tighten the clamp.
    • The original CAI coupling may need to be stretched onto the larger TB.
  14. Reconnect the MAF sensor plug and recheck all connections.
  15. Re-tighten the battery hold-down bracket.

Properly mounted 3.7L TB on the 3.0L manifold.
Additional Reference Documents: