Description
Mazda 20B-REW Twin Turbo Complete Engine For Sale
With a nominal displacement of 1,962 cc (654 cc × 3 rotors), the 20B-REW delivers the smooth, high-revving character associated with Mazda’s rotary engines while providing significantly greater torque than the two-rotor 13B-REW. The factory Japanese-market specification was rated at approximately 280 PS at 6,500 rpm and 402–407 Nm at 3,000 rpm.
The engine was produced for the 1990–1995 Eunos Cosmo JC, making it the production engine most closely associated with Mazda’s flagship JDM luxury coupe. The Cosmo was equipped from the factory with a four-speed electronically controlled automatic transmission.
This listing is particularly suited to customers looking for a complete JDM 20B-REW engine package, including the factory twin-turbo system, engine wiring harness and ECU where supplied. Having the original wiring and ECU together can be especially valuable for restoration projects and engine swaps because these components are specific to the Cosmo’s engine-management system.
Key Features
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Genuine Mazda 20B-REW rotary engine
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Three-rotor Wankel configuration
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1,962 cc nominal displacement
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Factory sequential twin-turbo system
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JDM Eunos Cosmo specification
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Approximately 280 PS @ 6,500 rpm
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Approximately 402–407 Nm @ 3,000 rpm
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Electronic fuel injection
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Six spark plugs — two per rotor
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High-revving rotary architecture
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Smooth three-rotor power delivery
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Factory engine management system
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Cosmo-specific ECU
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Factory engine wiring harness
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Suitable for restoration and performance projects
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Highly desirable JDM rotary engine
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Rare three-rotor production configuration
The 20B-REW’s three-rotor arrangement provides a distinctive combination of smoothness, torque and power delivery. It was offered exclusively in the Eunos Cosmo, while the same-generation Cosmo was also available with the smaller two-rotor 13B engine.
Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | Mazda |
| Engine Code | 20B-REW |
| Engine Type | Wankel Rotary |
| Rotor Configuration | 3 Rotor |
| Displacement | 1,962 cc |
| Chamber Size | 654 cc × 3 rotors |
| Aspiration | Sequential Twin Turbo |
| Turbochargers | Twin Hitachi turbochargers |
| Fuel System | Electronic Fuel Injection |
| Ignition | Twin-plug per rotor |
| Total Spark Plugs | 6 |
| Compression Ratio | Approximately 9.0:1 |
| Factory Power | 280 PS / approximately 276 hp |
| Maximum Power RPM | 6,500 rpm |
| Factory Torque | Approximately 402–407 Nm |
| Maximum Torque RPM | 3,000 rpm |
| Factory Boost | Approximately 0.65–0.7 bar, specification dependent |
| Factory Redline | Approximately 7,000 rpm |
| Original Application | Mazda Eunos Cosmo JC |
| Production Application | JDM only |
| Original Transmission | 4-speed electronically controlled automatic |
| Drive Configuration | Rear-wheel drive |
| Engine Management | Factory electronic ECU |
| Wiring | Factory Cosmo engine harness, when supplied |
Complete Engine Package
Package includes the following components:
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Mazda 20B-REW three-rotor engine
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Factory sequential twin-turbochargers
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Turbo manifolds and associated hardware
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Intake manifold
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Throttle body
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Fuel rails and injectors
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Factory ignition components
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Engine sensors
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Alternator
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Starter motor
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Factory engine wiring harness
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Factory Cosmo ECU
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Other attached accessories









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