RE Amemiya: The Mazda Rotary Specialist Behind FD3S Legends

If you own a Mazda rotary — RX-7, RX-8, or Eunos Cosmo — and you want the absolute best engine work money can buy, there is one destination: RE Amemiya in Chiba, Japan. Founded in 1974 by Isami Amemiya, RE Amemiya is the undisputed Mazda rotary specialist of the Japanese tuning world, having built some of the most powerful, most durable, and most famous Wankel engines in existence.

The Founder: Isami Amemiya

Isami Amemiya's passion for rotary engines began when he was a teenager in the late 1960s, watching Mazda's first rotary cars (Cosmo Sport, Luce R100) on Japanese roads. He became obsessed with the Wankel engine's unique character — the smoothness, the high revs, the otherworldly sound — and in 1974, he founded RE Amemiya (RE stands for "Rotary Engine") specifically to build and tune Mazda rotaries.

Over 50 years later, Amemiya has become the acknowledged master of the Mazda rotary. Other shops can tune RX-7s; Amemiya can build a 20B three-rotor engine from scratch, calculating apex seal clearances to the micron, and produce a rotary that holds 500+ HP for thousands of miles without issue.

Rotary Expertise

Amemiya's engineering focus is on solving the Wankel engine's fundamental problems:

1. Apex Seal Longevity

Factory Mazda apex seals are made of ferrous-tungsten alloy. They're good for 80,000-120,000 km under normal conditions. RE Amemiya has developed proprietary seal materials (a ceramic-infused composite) that extend life to 150,000+ km under normal use and allow significantly higher boost without failure.

2. Oil Injection Calibration

The rotary engine's metering oil pump (MOP) injects 2-stroke-like oil into the intake charge to lubricate apex seals. Too little oil = apex seal failure. Too much oil = carbon buildup. Amemiya has dialed-in MOP calibrations for street and race conditions that balance these competing needs.

3. Thermal Management

Rotary engines run hot — exhaust gas temperatures exceed 1,800°F at wide-open throttle. Amemiya's cooling system designs include oversized radiators, custom oil coolers, and strategic heat shielding that keeps rotaries within thermal limits even during extended high-power operation.

4. Porting Science

Amemiya has developed specific porting techniques — street port, bridge port, peripheral port — each optimized for different applications. Their bridge port FD3S builds produce 450-600 HP reliably; their peripheral port race engines exceed 700 HP.

Famous Builds

RE Amemiya FD3S Super Taikyu Race Car

RE Amemiya campaigned FD3S RX-7s in the Super Taikyu endurance racing series (Japanese equivalent of 25 Hours of Le Mans) in the early 2000s. Their cars regularly finished races with rebuilt Wankel engines still at full compression — a remarkable feat for a rotary engine pushed to race limits for 5+ hours.

RE Amemiya 20B Three-Rotor FD3S

Amemiya has built several 20B-REW three-rotor engines into RX-7 FD3S chassis. The 20B-REW is Mazda's rarest production rotary (only in the 1990-1996 Eunos Cosmo), and fitting one into an FD3S requires custom engine mounts, oil system modifications, and ECU tuning. Amemiya's 20B builds typically produce 500-700 HP and have appeared in Best Motoring videos.

RE Amemiya Custom Street FD3S

Amemiya builds custom street RX-7s for wealthy Japanese clients at prices exceeding ¥20 million ($130,000 USD). These cars start with a base FD3S and receive comprehensive rebuilds: new apex seals, forged rotating assembly, upgraded turbos, custom ECU tuning, aftermarket coilovers, and extensive aerodynamic modifications. The cars are driven on the street, not raced.

Signature Products

RE Amemiya Rotary Apex Seals

Proprietary apex seal material rated for higher boost and longer life than factory seals. 2mm standard, 3mm available for bridge port applications.

RE Amemiya Custom Porting

Street port, bridge port, and peripheral port options. Each type optimizes different rev ranges and power output.

RE Amemiya FD3S Body Kits

Wide-body kits with distinctive carbon fiber splitters and flared fenders. The "Amemiya aero" look is instantly recognizable on any FD3S.

RE Amemiya Intake Manifolds

Aluminum and composite intake manifolds optimized for rotary airflow characteristics. Match their porting work.

RE Amemiya Exhaust Systems

Full titanium exhaust systems designed specifically for rotary exhaust gas pulse characteristics. Unique sound profile.

Super Taikyu Heritage

RE Amemiya's Super Taikyu racing program (2001-2005 approximately) demonstrated that a rotary-engined RX-7 could compete in 5-hour endurance races against piston-engined competitors. Their entries regularly qualified in the top 5 of their class and occasionally won overall class victories.

The engineering challenge was keeping the rotary engine cool and the apex seals healthy for 5+ hours of wide-open-throttle abuse. Standard rotary engines cannot do this — they overheat and lose compression within 60-90 minutes. RE Amemiya's modifications (thermal barrier coatings, upgraded cooling, calibrated apex seal clearances) allowed their cars to complete full race distances.

Why RE Amemiya Matters

For Mazda rotary owners, RE Amemiya is the destination. Unlike piston engines where 10 different shops can rebuild a 2JZ-GTE with similar results, rotary engines require specialized knowledge that few shops possess. RE Amemiya has 50+ years of continuous rotary engine experience and is considered the definitive authority.

Today, RE Amemiya still operates from its Chiba workshop. Isami Amemiya is in his 70s but still actively supervises engine builds. His son, who grew up in the shop, has taken over day-to-day operations. The shop continues to build custom FD3S RX-7s, RX-8 race cars, and the occasional 20B three-rotor swap.

For any rotary enthusiast, a visit to RE Amemiya is the ultimate Mazda tuning pilgrimage.