How to Install an Acura TSX Throttle Body on an 8th Gen Honda Civic Si
Swapping out restrictive factory induction components for OEM-plus parts is one of the most cost-effective ways to pick up power in your garage.
The Short Answer (TL;DR)
Installing a 2006–2008 Acura TSX 64mm throttle body onto your 2006–2011 Honda Civic Si (K20Z3) takes about 1 to 2 hours. This direct-fit OEM upgrade replaces the restrictive 60mm stock unit to increase airflow, improve throttle response, and maximize top-end power when paired with an aftermarket intake and custom ECU calibration.
The DIY Process Overview
To perform this throttle body swap, you need basic hand tools including 10mm and 12mm sockets, ratchet extensions, pliers for coolant hose clamps, a fresh intake gasket, and rags to catch spilled coolant. Start by disconnecting the negative battery terminal and removing the intake arm to expose the factory throttle body.
Pinch and disconnect the two coolant bypass lines underneath the throttle body, plugging them quickly to prevent excessive coolant loss. Unplug the drive-by-wire harness connector, remove the four mounting bolts, and lift off the factory 60mm throttle body.
Clean the intake manifold mating surface thoroughly before installing your matched gasket. Mount the 64mm TSX throttle body, torque the mounting hardware evenly to 16 lb-ft in a crisscross pattern, reconnect the electrical harness, reinstall your coolant hoses, and perform an ECU idle relearn procedure once reassembled.
Why You Should Upgrade While You're In There
When you have the intake tract disassembled, leaving the stock, narrow intake tubing in place creates an immediate bottleneck right before your new larger throttle body. Upgrading to a 3-inch cold air intake and matching it with an ECU tune ensures your K20Z3 engine can properly meter the increased volume of incoming air without running lean.
Recommended Upgrade: Pair your throttle body swap with a high-flow 3.0-inch cold air intake system and an engine calibration tune to maximize mid-range torque and high-RPM horsepower gains.
Frequently Asked Questions
Do I need an adapter plate to mount a TSX throttle body to a K20Z3 manifold?
The 2006–2008 TSX throttle body bolts directly to the factory Civic Si RBC intake manifold bolt pattern. However, port-matching the manifold opening from 60mm to 64mm is recommended to eliminate airflow turbulence at the transition.
Will I need an ECU tune immediately after installing the TSX throttle body?
While the car can idle and drive on the factory ECU map after an idle relearn, recalibrating the ECU is strongly advised. The larger bore changes airflow dynamics across the RPM band, requiring adjusted fuel tables to prevent lean conditions under wide-open throttle.
