RBC Intake Manifold Adapters: ZDX Throttle Body Fit FAQ

RBC adapter and ZDX throttle body questions, answered

Which RBC intake manifold adapter do I need for my car?

It depends on your engine and whether you keep the stock throttle body or upgrade. The 2012-2015 Honda Civic Si RBC Intake Manifold Adapter Kit (product 2681146) fits 2012-2015 Civic Si, 2013-2015 Acura ILX 2.4L, 2009-2014 Acura TSX 2.4L, and 2008-2012 Accord 2.4L. It comes in two versions: one for the stock throttle body and one for the ZDX throttle body. If you already have an RBC or RRC manifold and only need to bolt on a 70mm ZDX/MDX throttle body, the standalone RBC Intake Manifold to 70mm J37 Throttle Body Adapter (product 2681147) is the simpler choice.

Will a 70mm J37 ZDX throttle body fit my RBC manifold?

Yes, with the correct adapter. The ZDX throttle body (part 16400-RYE-A11) has a 79 mm inlet that tapers to a 70 mm outlet at the manifold. The PRL adapter (product 2681147) is machined from 6061 aluminum to mate that throttle body to an RBC or RRC bolt pattern intake manifold. It uses an O-ring to seal against the manifold and an OEM Honda gasket to seal against the throttle body.

What is included in the ZDX throttle body adapter kit?

The ZDX Throttle Body Kit includes: (1) PRL Motorsports Anodized Throttle Body Adapter, (1) Section Vacuum Hose, (1) 90 Degree EVAP Fitting, and (1) Honda OEM Throttle Body Gasket. The adapter also has a 1/8" NPT port and 90-degree fitting to retain the factory EVAP purge.

Do I need a different intake manifold adapter if I keep the stock throttle body?

Yes. The full RBC Intake Manifold Adapter Kit (product 2681146) is available in a Stock Throttle Body version and a ZDX Throttle Body version. The stock version adapts the RBC/RRC manifold to your original drive-by-wire throttle body, while the ZDX version includes the parts to fit the larger 70mm J37 unit.

Will my factory injectors work with the RBC manifold?

Not always. The RBC intake manifold requires injector boring to the manifold itself to use factory-diameter 9th Gen Civic Si injectors; otherwise, standard K-Series (8th Gen Civic Si) style injectors must be used. Acura RDX injectors are also a popular solution. Plan for this machine work or injector change before the swap.

Can I reuse my original intake system with an RBC manifold?

No. Vehicles equipped with RBC or RRC intake manifolds require RBC/RRC-specific intake systems. Your factory intake tube or airbox will not line up correctly, so budget for a compatible intake as part of the swap.

Is port matching required for a 70mm ZDX throttle body?

PRL recommends port matching the intake manifold plenum for 70mm ZDX/MDX applications for optimal performance. It is not described as mandatory, but it helps smooth the transition from the throttle body to the manifold.

Which vehicles does the standalone 70mm J37 adapter fit?

The RBC Intake Manifold to 70mm J37 Throttle Body Adapter fits all 2012-2015 Civic Si, including RHD and international models, when used with an RBC or RRC bolt pattern intake manifold. It is designed for the ZDX or MDX/Pilot throttle body on that manifold.

Adapter and throttle body specs behind these answers

• RBC Intake Manifold to 70mm J37 (ZDX/ MDX) Throttle Body Adapter: Machined from 6061 aluminum; uses an O-ring to seal against the manifold and an OEM Honda gasket to seal against the throttle body. Explains the sealing method and material quality you can expect from the standalone adapter.

  

• RBC Intake Manifold to 70mm J37 (ZDX/ MDX) Throttle Body Adapter: Includes a 1/8" NPT port and 90-degree fitting to retain the factory EVAP purge. Confirms the adapter supports emissions plumbing without custom fabrication.
• 2012-2015 Honda Civic Si RBC Intake Manifold Adapter Kit: Kit includes the PRL intake manifold adapter flange and a throttle body adapter kit (stock or ZDX version). Shows that the full kit covers both the manifold-to-head and throttle body interfaces in one purchase.

  

• 2012-2015 Honda Civic Si RBC Intake Manifold Adapter Kit: Fits 2012-2015 Civic Si, 2013-2015 ILX 2.4L, 2009-2014 TSX 2.4L, and 2008-2012 Accord 2.4L, including 6MT, RHD, and international models. Defines the vehicle scope so you can quickly check if your car is listed.
• Genuine Honda / Acura ZDX Throttle Body: Genuine Honda/Acura part 16400-RYE-A11 with a 79 mm inlet that tapers to a 70 mm outlet at the manifold. Clarifies the size and OEM identity of the throttle body used in the 70mm J37 upgrade.
• Genuine Honda / Acura ZDX Throttle Body: Listed for Honda Civic Si and Acura ILX applications with the 2.4 engine and 6-speed manual transmission. Helps confirm whether this throttle body is intended for your specific model and drivetrain.

What the catalog does not confirm

The supplied records do not include torque specifications, detailed installation steps, or tuning requirements for either adapter or the throttle body. They also do not state whether the standalone adapter includes the intake manifold flange or coolant routing parts that come in the full kit. If you need those details, check the manufacturer's documentation or consult a qualified technician before ordering.

Similarly, the catalog does not list injector boring services or port matching as included services; these are described as requirements or recommendations to address separately. Always verify part numbers and compatibility against your specific vehicle identification number before purchase.