HKS Silicone Transition Coupler 3.5 To 4 Inch Blue Color

Silicone transition coupler designed to join 3.5" to 4" intake or charge piping while providing a durable, vibration-tolerant connection that resists compression and maintains alignment under repeated thermal cycling.

This Mishimoto-developed silicone transition coupler is engineered for reliable service in intake, intercooler, and custom piping systems. It offers a simple, robust method to adapt between two common pipe diameters without cutting or welding, and is available in multiple colors for visual integration with existing engine-bay components.

• 3.5" to 4" size — Provides an exact transition between 3.5-inch and 4-inch piping to simplify system layout and preserve internal flow geometry.
• Silicone construction — Flexible material allows for vibration absorption and slight misalignment while maintaining a secure seal between metal or composite pipes.
• Color options: black, blue, red — Multiple finishes enable match to factory or aftermarket intercooler and intake components for a coordinated appearance.
• Developed by Mishimoto — Designed and validated by a specialist in thermal and fluid-management components to meet the practical demands of engine bay installations.

Key functional advantages:

• Adaptability: Eliminates the need for custom-fabricated reducers when integrating components with differing diameters.
• Serviceability: Can be installed or removed quickly using standard hose clamps, facilitating maintenance and component swaps.
• Durability: Silicone construction provides resistance to ozone and many common automotive fluids while retaining flexibility across typical operating temperatures.

Use this transition coupler where a secure, leak-resistant join is required between 3.5" and 4" piping runs in intake, intercooler, or custom plumbing applications. The color choices support visual customization without affecting function.

Vendor: Mishimoto