Mazda Eunos Cosmo 20B
The Mazda Eunos Cosmo 20B was a Japanese-market luxury coupe built on the JC platform. It used Mazda’s 20B-REW three-rotor sequential twin-turbo rotary engine, a front-engine, rear-wheel-drive layout, and a four-speed automatic transmission.
Model Overview
The JC-series Eunos Cosmo was positioned as a high-specification personal luxury coupe within Mazda’s Eunos sales channel. The 20B version was the highest-output variant and remains notable for using a production three-rotor rotary engine.
The 20B-REW engine used three rotors, sequential twin turbochargers, electronic fuel injection, and a displacement of 1,962 cc using Mazda’s rotary-engine displacement convention. The model was sold in Japan and was not officially offered in the United States.
Core Specifications
| Model | Mazda Eunos Cosmo 20B |
|---|---|
| Chassis Code | JC |
| Model Years | 1990–1996 |
| Market | Japan |
| Body Style | Two-door luxury coupe |
| Layout | Front-engine, rear-wheel drive |
| Engine | 20B-REW three-rotor rotary |
| Displacement | 1,962 cc using Mazda rotary displacement convention |
| Induction | Sequential twin turbochargers |
| Horsepower | 280 PS / 276 hp at 6,500 rpm |
| Torque | 402 Nm / 296 lb-ft at 3,000 rpm |
| Transmission | 4-speed automatic |
| Wheelbase | 2,750 mm / 108.3 in |
| Length | 4,815 mm / 189.6 in |
| Width | 1,795 mm / 70.7 in |
| Height | 1,305 mm / 51.4 in |
| Curb Weight | Approximately 1,610 kg / 3,549 lb, depending on version and source |
The Eunos Cosmo was also offered with two-rotor rotary engines. This entry refers specifically to the JC-series 20B three-rotor version.
Engineering Character
Three-Rotor Rotary Engine
The 20B-REW used three rotors rather than the two-rotor configuration found in many other Mazda rotary models. The engine produced 280 PS and 402 Nm in factory form.
Sequential Twin Turbochargers
The factory induction system used sequential twin turbochargers. The configuration was designed to provide low-speed response and higher-rpm airflow from the same engine package.
Luxury Coupe Positioning
The Cosmo 20B was not a lightweight sports car. Its body size, equipment level, automatic transmission, and cabin specification placed it in the Japanese-market luxury coupe segment.
Rear-Wheel Drive Layout
The car used a front-engine, rear-wheel-drive layout. This separated it from front-wheel-drive personal coupes and aligned it more closely with larger Japanese grand touring coupes.
Model Notes
| 20B Version | Highest-output JC-series Cosmo version. Used the 20B-REW three-rotor sequential twin-turbo rotary engine. |
|---|---|
| Transmission | The 20B model was paired with a four-speed automatic transmission rather than a manual gearbox. |
| Market Position | Sold through Mazda’s Eunos channel in Japan as a premium coupe rather than as a stripped performance model. |
Modern Enthusiast Relevance
- Production three-rotor Mazda rotary engine
- Sequential twin-turbo induction
- Japanese-market luxury coupe configuration
- Front-engine, rear-wheel-drive layout
- 20B-REW engine family
- Automatic-only grand touring specification
- Distinct separation from RX-7 and RX-8 model lines
Comparable Cars
Mazda RX-7 FD
Two-rotor Mazda rotary sports car from the same broad era. The RX-7 used a lighter, more sports-car-focused platform than the Eunos Cosmo.
Toyota Soarer
Japanese luxury coupe with rear-wheel drive and high-output engine options. It occupied a similar market segment but used piston engines rather than a rotary engine.
Nissan Leopard
Japanese-market luxury coupe with front-engine, rear-wheel-drive packaging. It is a segment comparison rather than a powertrain comparison.
Mitsubishi GTO / 3000GT
Japanese grand touring coupe from the same period. It used a twin-turbo piston V6 and all-wheel drive in higher-performance versions.
Buying And Ownership Notes
The Eunos Cosmo 20B is a specialist Japanese-market vehicle. Evaluation should focus on rotary-engine compression, turbocharger condition, cooling-system condition, automatic transmission operation, electronic systems, interior equipment, and imported-vehicle documentation.
Parts availability varies by component. Standard service items, rotary-engine support, and 20B-specific parts should be evaluated separately from body, trim, electronics, and Eunos-specific interior components.
MSC Taxonomy
Summary
The Mazda Eunos Cosmo 20B is a Japanese-market JC-series luxury coupe powered by the 20B-REW three-rotor sequential twin-turbo rotary engine. It combined a front-engine, rear-wheel-drive layout with a four-speed automatic transmission and premium coupe positioning.