Description

Mazda 20b rotary engine

Description and Details:
The 20B engine is part of the Mazda Wankel engine family and represents an evolution of the 13B engine, featuring a triple-rotor design . Each of its three chambers displaces 654 cc, resulting in a total displacement of 1,962 cc (approximately 2.0 liters) . The engine’s unique rotary design, with triangular rotors rotating within a chamber, allows it to achieve high RPMs and deliver power linearly . This design contributes to its compact size and lightweight nature, which aids in vehicle balance and agility .

The most common production version is the 20B-REW, which was exclusively used in the 1990-1995 Eunos Cosmo . This variant is notable for being the first sequential twin-turbocharged production engine of its kind .

Key Specifications (20B-REW Production Engine):

Capacity: 1,962 cc (654 cc x 3 rotors)

Induction: Sequential Twin-turbochargers

Compression Ratio: 9.0:1

Horsepower: Claimed 280 PS (206 kW) , or 276 hp at 6,500 rpm

Torque: 407 N·m (300 lbf·ft) , or 296 ft/lb at 3,000 rpm

Boost Pressure: 0.7 bar (10 psi; 70 kPa) from twin sequential turbochargers

Dimensions: 672mm (L) x 549mm (W) x 520mm (H) with accessories

Weight: 350kg dry weight with manifolds etc. (production 20B-REW)

Fuel System: Electronic Fuel Injection

Cooling System: Liquid cooling system

Lubrication System: Utilizes a lubrication system

Racing Variants:
A naturally aspirated racing variant, based on the 13G engine and later renamed 20B, produced around 440 hp at 8,500 rpm and 289 lb/ft of torque at 8,000 rpm . This version was significantly lighter at 143kg (dry sump) . The 13G used a factory peripheral intake port for racing, while the production 20B used side intake ports .

Despite its performance capabilities, the 20B engine faced challenges with fuel consumption and emissions regulations, leading to its limited production . However, its unique characteristics and contribution to Mazda’s engineering legacy make it highly cherished by enthusiasts