Mazda RX-7 FD3S: 13B-REW Thermal Efficiency & Apex Seal Blueprint
1. Principles of the 13B-REW Twin Rotary
The 13B-REW featured in the 1992–2002 Mazda RX-7 FD3S was the world's first mass-produced sequential twin-turbocharged rotary engine. Displacing 1.3 liters across two triangular rotors, it achieves remarkable power density, revving smoothly to 8,000 RPM while weighing under 220 kg engine dress weight.
However, Wankel rotary engines generate significantly higher thermal loads than reciprocating piston engines because combustion occurs in the same housing zone continuously.
2. Apex Seal Selection for High Boost
When exceeding stock boost pressure (0.75 Bar / 10.8 PSI), replacing original 2-piece OEM cast apex seals is critical:
- OEM 2mm Cast Iron Seals: Excellent seal retention at low RPM, but prone to shattering instantly if detonation occurs under boost.
- 2mm Super Seals / IANETTI Ceramic: Exceptional thermal tolerance up to 500 WHP. High resistance to detonation score damage.
- 3mm Steel Apex Conversion: Requires rotor slot milling. Provides massive impact resistance for 600+ WHP drag and drift applications.
3. Sequential Turbo vs. Single Turbo Modernization
While the OEM Hitachi sequential turbo system offers rapid response below 3,000 RPM, the complex vacuum solenoid system contains over 60 vacuum hoses ("the rat's nest"). Modern builders favor single scroll Garrett G-Series or BorgWarner EFR turbos, which yield cleaner engine bays, vastly lower under-hood heat, and superior boost stability.
4. External Manufacturer Links
Explore official Mazda rotary heritage archives: