Honda ZDX Throttle Body 16400-RYE-A11

Honda ZDX Throttle Body (16400-RYE-A11) - 8th Gen Civic Si Big-Bore Upgrade

The stock K-series drive-by-wire throttle body is undersized, and on a modified engine that smaller bore becomes a restriction that caps your power gains. The Honda ZDX throttle body (part number 16400-RYE-A11) is a bigger-bore drive-by-wire unit from the J37 V6, and it's become a go-to, cost-effective upgrade on the 8th gen Civic Si. More throttle body diameter means more air into the cylinders, which can translate to more power once the rest of the combo is there to use it.

When To Do This Upgrade

Save this one for after the essentials. We recommend the ZDX throttle body once you've already installed your intake, header, exhaust, and a tuning solution like Hondata FlashPro. A bigger throttle body makes its difference on an engine that's already breathing hard, so on an otherwise stock car it's not where you'd start. On a bolt-on, tuned Si, it's the airflow upgrade that keeps the throttle body from being the limit.

OEM Honda Quality At A Better Price

Because it's a genuine OEM Honda part from the ZDX/J37, you get factory reliability and build quality rather than rolling the dice on an unknown aftermarket piece. And the cost of this 80mm/70mm OEM throttle body rivals or beats most dedicated aftermarket options, so you're getting more bore for your money with OEM peace of mind.

What You'll Need

Two things to plan for before you buy:

• ZDX adapter is required to run this throttle body on RBC and PRC flanged manifolds, since the ZDX flange doesn't match those directly.
• Tuning is required after installation. The ECU has to be set up for the larger throttle body, so plan on a tune (FlashPro or equivalent) as part of the install.

Fitment

A common drive-by-wire throttle body upgrade for the 8th gen Honda Civic Si (K20Z3). Requires an adapter for RBC/PRC manifolds and a tune after installation. Confirm your manifold and adapter needs before ordering.

If your bolt-on, tuned Si has the throttle body as its next restriction, the ZDX 16400-RYE-A11 is the proven, budget-friendly way to open it up: an OEM big-bore drive-by-wire unit with factory reliability. Just plan on the correct adapter for your manifold and a tune to finish it.