Why Use a K20 Intake Manifold on a K24?

K20 intake manifolds are designed for higher RPM airflow, making them a popular upgrade for K24 builds.

Benefits of This Setup:

• Improved airflow efficiency
• Better throttle response
• Increased high-RPM performance
• Ideal for naturally aspirated and turbo builds

INSATLLATION INSTRUCTION:
Begin by the use of the 6.5mm or ¼ drill bit to finish the blind hole in the adapter. You then wish to install the manifold and adapter on the head. This will be sure you are properly positioning the hole. Once you have marked where You need to drill remove the manifold and adapter. Place tape or plug the holes on the head for intake and coolant to prevent anything from getting inside. You are going to be tapping at least 11mm depth (the depth of the bolt) but shouldn’t need more than 14mm of depth.

You’ll be able to apply tape on the drill bit to ensure not to drill too deep. Once you drill the hole You are going to run your tap. Be careful not to tap too deep. You’ll be able to start the thread with a standard tap but you must finish it the use of a bottoming tap. This will allow the bolt to use among the tapped hole. Slowly start to tap the head and check fitment of your adapter continuously. You need the adapter to hold snug but not tap the hole to far.

What This Recirculation Fitting Does

This fitting is a small but critical component that allows proper routing of coolant or air recirculation when adapting a K20 manifold onto a K24 head.

Key Functions:

• Enables proper recirculation flow
• Ensures compatibility between K24 head and K20 manifold
• Prevents leaks and improper routing
• Supports clean and reliable installation

The Intake Manifold Adapter can be installed either the use of our spring loaded tab or by tapping the head. We use original Bond or similar gasket maker as it provides a strong seal and when the use of the spring loaded tab when the adapter isn’t under pressure there will be no chance of leak. The spring loaded tab holds the adapter down with constant spring pressure to ensure a tight fit and seal. The other option is the use of the provided blind hole You’ll be able to easily tap the head for the second hole. Tapping the head will require a 6.5mm drill bit (to finish the blind hole in the adapter), 5mm drill bit (to drill the head), and M6x1.0 Tap.

Product Overview: Recirculation Adapter Fitting

Designed for precision and durability, this fitting is built to handle the demands of performance builds.

Key Features:

• Compatible with K24 engines using K20 intake manifolds
• Precision-machined for proper fitment
• Durable aluminum construction (silver finish)
• Corrosion-resistant and long-lasting
• Essential for proper manifold conversion

The K24 Intake Manifold Adapter is a simple and easy way to install K20 style manifold on K24 heads. The recirculation fitting on K24s is typically part of the intake manifold which isn’t on K20 intake manifolds. We have designed the adapter to work with all K24 heads including the K24Z-Series (R40) heads. This can also be used to install K20 manifolds or cut RBC manifolds on 9th gen Civic si

Compatible Engines

Honda / Acura K-Series:

• K24 / K24A engines
• K20-style intake manifold conversions

(Verify compatibility with your specific manifold and setup.)

APPLICATION:The K24 Intake Manifold Adapter is a simple and easy way to install K20 style manifold on K24 heads. The recirculation fitting on K24s is typically part of the intake manifold which isn’t on K20 intake manifolds.

Why This Part Is Important

Without proper recirculation routing, your intake manifold conversion may result in:

• Coolant leaks
• Improper engine operation
• Reduced reliability
• Incomplete or unsafe installation

This fitting ensures your swap is done correctly and cleanly.

This can also be used to install K20 manifolds or cut RBC manifolds on 9th gen Civic si as the water bypass is fairly different and You are going to not need an intake manifold adapter when the use of the adapter.

Ideal For:

• K24 performance builds
• K20 intake manifold conversions
• Naturally aspirated and turbo setups
• Engine swaps and custom builds

The adapter lowers intake air temps as coolant is no longer connected the intake manifold.
WYAS TO INSTALL:The Intake Manifold Adapter can be installed either the use of our spring loaded tab or by tapping the head.

Installation Notes

• Installs into recirculation port on K24 head/manifold setup
• Ensure proper sealing during installation
• Verify hose routing and compatibility
• Recommended during manifold swap process

Performance Benefits

While small, this fitting supports:

• Proper engine function
• Reliable cooling/recirculation flow
• Clean and complete installation
• Long-term durability

The adapter also features a 1/8 NPT port for a coolant temp sensor commonly used in swap cars.

Frequently Asked Questions

Is this required for a K20 manifold swap on a K24?

Yes, it helps ensure proper recirculation and prevents issues.

Does this increase horsepower?

Not directly, but it enables a performance-enhancing intake manifold setup.

Is installation difficult?

It’s straightforward but should be installed carefully during the manifold swap.

Conclusion

This K24 to K20 intake manifold adapter recirculation fitting is a small but essential component for a successful manifold conversion. Designed for durability and proper fitment, it ensures your K-series build runs cleanly and reliably.