FD3S Rx-7 Twin Scroll T4 Turbo Manifold

FD3S Rx-7 Twin-Scroll Turbo Manifold

Designed specifically for the Mazda FD3S RX-7, the Metal Sculpt Twin-Scroll Turbo Manifold is engineered to deliver maximum performance, durability, and repeatability. Every manifold is built in-house using precision CNC-machined components and proven fabrication methods developed through years of rotary performance work.

Each manifold begins with 16mm laser-cut stainless steel flanges which are then CNC ported and profiled. The exhaust flange transitions smoothly from the factory 13B exhaust port shape into the internal diameter of the 1.5″ runners, while the T4 turbo flange is CNC machined to transition from the circular runner profile into the rectangular twin-scroll T4 turbine inlet. This process improves flow consistency and eliminates the abrupt transitions commonly found in hand-fabricated manifolds.

Every manifold is fully back-purged during welding to ensure maximum weld integrity and internal flow. Following fabrication, both the exhaust flange and T4 flange are surfaced in dedicated machining fixtures to ensure perfectly flat sealing surfaces and long-term reliability under extreme thermal cycling.

Features

• Twin-scroll divided T4 turbine inlet
• Dual 40mm wastegate provisions
• 16mm CNC-profiled stainless steel flanges
• Fully back-purged TIG welded construction
• Optional EGT/EMAP/Pre turbo 02 sensor ports
• Compatible with our 4-inch dump pipe and full exhaust system
• Available with recirculated or atmospheric vented wastegate configurations
• Clears the factory lower intake manifold and chassis rail heater pipe without modification

Turbocharger Compatibility

The manifold is designed to accommodate turbochargers up to Garrett G40 / Borgwarner S300 sizing without modification. Larger-frame turbochargers, including Garrett G42 and BorgWarner S400-series units, will require an AST delete tank to provide adequate compressor housing clearance.

Why Twin-Scroll?

Unlike conventional open-entry manifolds, the Metal Sculpt manifold maintains complete separation of the rotary engine’s exhaust pulses all the way to the turbine housing. By keeping exhaust pulses isolated, the turbine wheel receives stronger and more efficient pulse energy, resulting in faster spool-up, improved transient response, and reduced exhaust reversion.

The twin-scroll design is paired with dual 40mm wastegates with excellent flow priority. This provides superior boost control compared a single wastegate arrangement and reduces the possibility of boost creep.

Whether you’re building a responsive street car or a high-power race application, the Metal Sculpt Twin-Scroll Turbo Manifold delivers the flow capacity, durability, and manufacturing precision required to support serious rotary performance.