Description

STM Billet Water Neck for Evo 6/7/8/9 (CT9-BWN)

Firstly, Buy STM Billet Water Neck for Evo 6/7/8/9 (CT9-BWN) with interchangeable fittings and NPT sensor port. Upgrade the cooling system on your Mitsubishi Lancer Evolution with the STM Billet Water Neck for Evo 6/7/8/9 (CT9-BWN), a high-quality billet aluminum replacement designed for Evo 6, Evo 7, Evo 8, and Evo 9 4G63 applications. Built by STM in the USA, this water neck provides a clean, durable solution for enthusiasts who want improved cooling-system flexibility, additional sensor capability, and interchangeable outlet options for factory or custom radiator setups.

The water neck is an important part of the engine cooling system because it provides the connection between the cylinder head and upper radiator hose. On a modified 4G63-powered Evolution, the factory-style arrangement may not always provide the clearance or hose configuration needed for a larger turbocharger, exhaust manifold, aftermarket radiator, or custom cooling system. The STM Billet Water Neck gives Evo owners more flexibility while maintaining a direct bolt-on installation for the applicable vehicles.

STM Billet Water Neck for Evo 6/7/8/9

The STM Billet Water Neck for Evo 6/7/8/9 is manufactured from billet aluminum and features interchangeable outlet fittings, allowing the configuration to be matched to different cooling-system requirements. STM offers options for the factory-style 35mm upper radiator hose as well as -10AN, -12AN, and -16AN connections. The water neck can also be purchased without an outlet fitting for custom installations.

One of the most useful features is the integrated 1/8-inch NPT sensor port, which provides a convenient location for a water-temperature sensor or gauge installation. A supplied NPT plug can be used when the sensor provision is not required. This makes the water neck particularly useful for street cars, track cars, and modified Evo builds where monitoring coolant temperature is an important part of engine management and cooling-system setup.

Designed for Mitsubishi Evo 4G63 Builds

The CT9-BWN is designed specifically around Mitsubishi Lancer Evolution 6, 7, 8, and 9 applications. These vehicles use the legendary 4G63 turbocharged four-cylinder engine, and many examples have been upgraded with aftermarket turbochargers, exhaust manifolds, radiators, intercooler systems, and other performance components.

Firstly, the billet construction provides a strong and durable alternative to a worn or damaged factory water neck. Secondly, the interchangeable outlet system allows the cooling system to be configured around the needs of your particular build. Thirdly, the integrated NPT sensor provision provides a clean location for adding coolant-temperature monitoring without requiring additional modifications to the cooling system.

Buy STM Billet Water Neck for Evo 6/7/8/9 (CT9-BWN) with interchangeable fittings and NPT sensor port. Shop this 4G63 cooling upgrade at Evomotorparts.

Features and Benefits

• Designed for Mitsubishi Lancer Evolution 6, 7, 8, and 9
• Compatible with applicable 4G63-powered Evo applications
• Billet aluminum construction
• Direct bolt-on design
• Interchangeable water outlet fittings
• Available for 35mm stock-size upper radiator hose
• Available with -10AN, -12AN, or -16AN outlet configurations
• Integrated 1/8-inch NPT temperature-sensor port
• NPT plug included when the sensor port is not being used
• Stainless mounting hardware included
• Made in-house in the USA by STM
• Lifetime warranty against manufacturing defects to the original purchaser, according to STM
• Not compatible with Evo 1–5 applications

Flexible Cooling-System Configuration

One of the biggest advantages of the STM water neck is its interchangeable fitting design. A factory-style 35mm outlet can be used when retaining the original-style upper radiator hose, while AN fittings provide additional flexibility for custom radiator and hose configurations. STM lists -10AN, -12AN, and -16AN options, making the CT9-BWN suitable for a variety of street, competition, and high-performance cooling-system layouts.

This flexibility can be especially useful when working around aftermarket turbochargers and exhaust manifolds. Modified Evo engine bays often require careful attention to coolant-hose routing and component clearance. A configurable water neck can help simplify the installation while giving the builder greater control over the final cooling-system layout.

1/8 NPT Water Temperature Sensor Provision

For enthusiasts monitoring engine temperatures, the built-in 1/8-inch NPT bung is another major benefit. Instead of adding a separate sensor adapter elsewhere in the cooling system, the STM water neck provides a dedicated location for a compatible water-temperature sensor.

This can be useful for aftermarket gauges and monitoring systems, particularly on modified 4G63 engines that see increased boost, higher power output, track use, or demanding driving conditions. When the sensor port is not required, the included NPT plug can be installed to seal the provision.

What’s Included

The STM CT9-BWN package includes:

• 1 × STM Billet Water Neck
• 1 × 1/8-inch NPT plug
• 3 × M6x16 stainless-steel mounting bolts
• 1 × STM outlet fitting with O-ring when the selected configuration includes a fitting

The outlet fitting should be selected according to the intended cooling-system configuration. STM also offers replacement and alternate fittings separately, allowing the setup to be changed later if the vehicle’s cooling system is upgraded.

Fitment and Applications

The STM Billet Water Neck is intended for:

• Mitsubishi Lancer Evolution VI
• Mitsubishi Lancer Evolution VII
• Mitsubishi Lancer Evolution VIII
• Mitsubishi Lancer Evolution IX
• 4G63 turbocharged engine applications
• Factory-style or modified cooling systems
• Street, performance, and track-oriented Evo builds

This part is not designed for Mitsubishi Evolution 1–5, so buyers should confirm their vehicle generation before ordering. The available outlet configuration should also be selected based on the radiator hose and cooling-system setup being used.

Why Upgrade Your Evo Cooling System?

Replacing an aging factory component with a quality billet water neck can be a worthwhile part of a larger cooling-system refresh. The STM design combines durability, sensor functionality, and fitting flexibility in one component, making it particularly well suited to enthusiasts who are already upgrading other parts of their Evo’s cooling system.

Whether you are restoring an Evo 6, building an Evo 7 or Evo 8 street car, maintaining an Evo 9, or assembling a high-performance 4G63 engine setup, the CT9-BWN offers a practical way to improve the water-neck portion of the cooling system while maintaining a clean engine-bay appearance.

Frequently Asked Questions

What Evo models does the STM CT9-BWN fit?

The STM CT9-BWN is designed for Mitsubishi Lancer Evolution 6, 7, 8, and 9 applications. It is not compatible with Evo 1–5.

Is the STM water neck made from billet aluminum?

Yes. STM lists the CT9-BWN as a billet aluminum water neck designed as a direct bolt-on component for the applicable Evo applications.

Does it work with the factory upper radiator hose?

Yes. STM offers a 35mm stock-size outlet configuration for the factory-style upper radiator hose. Alternative -10AN, -12AN, and -16AN fittings are also available for custom cooling-system configurations.

Can I install a water-temperature sensor?

Yes. The water neck features an integrated 1/8-inch NPT bung for a compatible water-temperature sensor. A supplied NPT plug can be used if the port is not needed.

Is this suitable for a modified 4G63?

Yes. Its interchangeable outlet system and sensor provision make it particularly useful for modified Evo cooling systems, including setups using custom radiator hoses or AN plumbing.

Can the outlet fitting be changed later?

Yes. STM offers replacement and alternate fittings, allowing the water neck configuration to be changed if the cooling system is modified in the future.

Is the STM CT9-BWN a direct bolt-on?

STM describes the water neck as a direct bolt-on component for the applicable Evo 6/7/8/9 applications. Always verify your vehicle and cooling-system configuration before ordering.

What other parts might I need?

Depending on your setup, you may need the appropriate upper radiator hose, AN hose and fittings, water-temperature sensor, radiator, thermostat, clamps, or other cooling-system components. The correct parts will depend on whether your vehicle retains the factory-style cooling configuration or uses a custom radiator and hose layout.

Conclusion

The STM Billet Water Neck for Evo 6/7/8/9 (CT9-BWN) is a durable and versatile cooling-system upgrade for Mitsubishi Evolution enthusiasts looking to replace an aging factory component, add convenient water-temperature monitoring, or gain greater flexibility when designing a custom radiator and hose configuration, with billet aluminum construction, interchangeable 35mm and AN outlet options, stainless mounting hardware, and direct-fit compatibility for applicable Evo 6, 7, 8, and 9 4G63 applications making it a practical choice for street cars, performance builds, track vehicles, and long-term Evo projects, so shop and order your STM CT9-BWN billet water neck and other Mitsubishi Evo parts from evomotorparts.com today and keep your 4G63 cooling system ready for the road or track.

Buy STM Billet Water Neck for Evo 6/7/8/9 (CT9-BWN) with interchangeable fittings and NPT sensor port, Shop this 4G63 cooling upgrade at Evomotorparts.