What Makes the 13B‑REW a Rotary Legend

The 13B‑REW is the twin‑turbocharged evolution of Mazda’s Wankel rotary engine, first appearing in the third‑generation RX‑7 (FD3S) from 1992. Its compact design, low rotating mass, and ability to rev past 8,000 RPM out of the box made it a standout in the 1990s sports‑car scene. Unlike piston engines, the rotary uses a triangular rotor orbiting within an epitrochoidal housing, producing three power pulses per rotor revolution. This gives a remarkably smooth power delivery and a unique sound that enthusiasts crave.

Key technical specs of the stock 13B‑REW include:

  • Displacement: 1.3 L (two rotors, 654 cc each)
  • Compression ratio: 9.0:1
  • Stock power: 255 PS (188 kW) at 6,500 RPM (Japanese spec)
  • Stock torque: 294 Nm (217 lb‑ft) at 5,000 RPM
  • Sequential twin turbos: Hitachi HT‑10 and HT‑12

While the stock engine is impressive, its sequential turbo system is complex and prone to boost‑control issues. Upgrading to a single, larger turbo from Greddy simplifies the setup and unlocks substantial power gains.

Why Greddy Components Are a Trusted Choice for Rotary Upgrades

Greddy (Trust) has been a dominant force in Japanese aftermarket performance since the 1970s. Their rotary‑specific parts are engineered to handle the unique thermal and stress characteristics of the 13B‑REW. Here are the primary benefits of choosing Greddy over generic components:

  • Proven Flow Design: Greddy turbochargers, such as the T67 and T88 series, are designed with large compressor wheels and efficient turbine housings that match the rotary’s exhaust pulse pattern.
  • Material Quality: Greddy uses high‑nickel cast iron for exhaust manifolds and turbine housings, resisting cracking under extreme heat cycles.
  • Bolt‑On Convenience: Many Greddy kits include all necessary brackets, gaskets, and hardware, reducing fabrication time.
  • Reputation for Reliability: The rotary community has decades of positive feedback on Greddy setups, with many cars running reliably at 400–600 whp on pump gas.

Core Greddy Components for Your 13B‑REW Build

1. Turbocharger Kit

The heart of the upgrade is the Greddy T67‑25G or T88‑34D turbo kit. These single‑turbo conversions eliminate the stock sequential system. The T67 is ideal for street‑focused builds (400–500 whp), while the T88 can push past 700 whp with proper supporting mods. The kit typically includes a cast‑iron exhaust manifold, downpipe, oil and water lines, and a wastegate.

2. Intercooler and Piping

Greddy’s front‑mount intercoolers (e.g., the 2‑row or 3‑row units) are matched to the turbo’s flow. Their cast aluminum end tanks reduce pressure drop, and the 3‑inch charge piping supports high boost without restriction. Proper intercooling is critical on a rotary because the engine’s high exhaust gas temperature (EGT) places extra heat load on the intake charge.

3. Exhaust System

A Greddy Power Extreme II or Ti‑C cat‑back exhaust reduces backpressure and improves spool time. Look for a 3‑inch mandrel‑bent system with a resonated mid‑pipe to keep noise manageable. A divorced downpipe that separates wastegate flow is recommended to prevent turbine backpressure spikes.

4. Fuel System Upgrades

Rotary engines are sensitive to lean conditions. Greddy’s fuel rails, pressure regulators, and larger injectors (from 550 cc to 2000 cc) ensure adequate fuel delivery. Pairing these with a Greddy E‑Manage Ultimate or a standalone ECU (e.g., Haltech, Link, or Adaptronic) is strongly advised for safe tuning.

5. Oil Cooling and Management

The 13B‑REW’s oil system must handle increased heat. A Greddy oil cooler with a thermostatic sandwich plate helps keep oil temperatures below 110°C. Consider upgrading the oil pump to a modified or aftermarket unit to ensure consistent pressure at high RPM.

Installation: What You Need to Know

Installing a Greddy turbo kit on a 13B‑REW is not a simple weekend job. Expect to spend 40–80 hours of labor, depending on experience and the scope of supporting mods.

  • Engine Bay Preparation: Remove the stock twins, intercooler, and airbox. The engine bay should be cleaned and inspected for oil leaks.
  • Fitment Considerations: Greddy’s manifold positions the turbo slightly lower than stock. Check clearance with your brake master cylinder and hood liner. You may need to relocate the power steering reservoir or trim the frame rail.
  • Professional Tuning: After installation, a dyno tune is non‑negotiable. Rotary engines have narrow safe air‑fuel ratio windows (11.5:1 under boost); an untuned engine can suffer from knock and apex seal failure.
  • Breaking In: After reassembly, perform a heat cycle procedure (idle for 10 minutes, then cool) before driving. The first 500 miles should be gentle with varying RPM.

Expected Performance Gains

With a Greddy T67 kit, 3‑inch intercooler, and proper fuel and tuning, a stock‑ported 13B‑REW can produce 400–450 whp on 93 octane pump gas. A street‑ported engine (bridge or street port) with the T88 can reach 550–650 whp. Torque peaks earlier and holds flatter than the stock sequential setup, making the car far more responsive in the mid‑range.

On the track, expect a 1‑second improvement in 60‑130 mph times, and a power‑to‑weight ratio comparable to modern supercars. Be aware that traction becomes a challenge, especially on stock suspension. Upgraded tires, coilovers, and a limited‑slip differential are recommended to put the power down.

Maintenance That Prolongs Engine Life

A Greddy‑built 13B‑REW demands consistent care. Follow these guidelines to avoid common rotary failures:

  • Oil Changes: Use a 10W‑40 or 20W‑50 synthetic oil with high zinc content (e.g., Brad Penn or Red Line). Change every 2,000–3,000 miles or after every track day.
  • Spark Plugs and Wires: Upgrade to NGK 9‑series plugs (BR9EQ‑14) and fresh silicone leads every 10,000 miles. Rotary engines are hard on plugs.
  • Coolant System: Flush and refill with distilled water and Evans Waterless Coolant or a high‑quality ethylene glycol mix. Ensure the cooling system is burped of air pockets.
  • Check Boost Leaks: Rotary engines are sensitive to unmetered air. Inspect all intake and intercooler couplings monthly.
  • Premix Fuel (if required): For high‑power builds, adding 1–1.5 ounces of Idemitsu or Motul 710 two‑stroke oil per tank of fuel helps lubricate apex seals.

Common Pitfalls to Avoid

Even with high‑quality Greddy parts, mistakes can cost time and money. Here are the most frequent issues:

  • Underestimating Cooling Needs: A single large turbo generates more heat than the stock twins. A stock radiator will not cope; upgrade to a Koyo or Mishimoto triple‑pass radiator.
  • Skipping the Pressure Regulator: High‑flow injectors require a rising‑rate fuel pressure regulator to maintain consistent fueling. Fitting a Greddy 10‑series regulator is cheap insurance.
  • Ignoring the Apex Seals: If the engine has high mileage (>80,000 miles), consider rebuilding the rotors with fresh OEM or Atkins seals before adding boost. New seals ensure the engine can handle the increased cylinder pressure.
  • Poor Wiring: The Greddy E‑Manage or standalone ECU requires proper soldering and shielding. Using crimp connectors or poor grounds can cause misfires and inconsistent tuning.

Budgeting for the Build

A complete Greddy conversion on a 13B‑REW is not cheap. Plan for the following approximate costs (USD, parts only):

  • Greddy turbo kit (T67): $2,200–$2,800
  • Intercooler and piping kit: $800–$1,200
  • Fuel system (injectors, rail, pump, regulator): $1,200–$1,800
  • Exhaust system: $600–$1,100
  • Standalone ECU and tuning: $1,500–$2,500 (including dyno time)
  • Radiator and oil cooler: $600–$1,000
  • Miscellaneous (gaskets, lines, fittings): $300–$500

Total parts: $7,200–$10,900. Professional installation can add $1,500–$4,000. This is a serious investment, but the result is a car that reliably outperforms many modern platforms.

Final Thoughts: Is the Greddy 13B‑REW Right for You?

Upgrading to a 13B REW built with Greddy components transforms the RX‑7 from a cult classic into a genuine performance threat. The combination of rotary lightness and Greddy’s proven engineering yields a powerband that is intoxicatingly responsive and linear. However, this is not a build for the faint of heart. It requires meticulous installation, professional tuning, and ongoing maintenance. If you are ready to invest the time, budget, and care, you will be rewarded with one of the most engaging driving experiences available.

For further reading on rotary engine theory and tuning strategies, check out resources from Rotary Aviation and RX‑7 Club forums. Greddy’s official product catalog can be found at Greddy Performance Products.