JDM Mazda 13B-RE Cosmo Rotary Engine 2.0L Twin-Turbo – Auto Trans Longblock for JC Cosmo & RX-7 Swaps

The Mazda 13B-RE is a 1.3-liter, twin-turbocharged 2-rotor Wankel rotary engine produced exclusively for the Eunos Cosmo (JC series) from 1990 to 1995. While often confused with the 13B-REW found in the RX-7 FD, the 13B-RE features unique larger intake ports, smaller exhaust port sleeves, and a luxury-oriented tune designed for smooth power delivery rather than peak horsepower . This engine was only available with a 4-speed automatic transmission from the factory, making it a rare and distinctive option for rotary enthusiasts building comfortable GT cars or performing unique swaps . With its massive intake port potential, the 13B-RE is considered an excellent foundation for high-performance porting and turbo upgrades

• Massive Intake Ports: The 13B-RE features significantly larger secondary intake ports than the 13B-REW found in the RX-7 FD. The intake runners are also larger in diameter, creating exceptional flow potential for ported builds . Many builders prefer the 13B-RE intake manifold for high-horsepower applications.

• Automatic-Only Configuration: Unlike the RX-7's 13B-REW, the Cosmo 13B-RE was only offered with a 4-speed automatic transmission from the factory. The engine's ECU, wiring harness, and tune are all designed specifically for automatic operation .

• Unique Exhaust Port Sleeves: The 13B-RE uses smaller steel exhaust port inserts compared to the 13B-REW. These restrict top-end power but can be replaced with RX-7 FD exhaust sleeves for improved flow . Many builders swap to 13B-REW rotor housings or port the existing sleeves.

• Hitachi Twin-Turbo System: Unlike the RX-7 FD's dual HT-12 turbos, the 13B-RE uses a smaller HT-10 primary turbo and larger HT-15 secondary turbo in a sequential configuration. The smaller primary turbo spools quickly for reduced lag, prioritizing smooth response over peak power .

• Lower Factory Boost: The 13B-RE runs lower factory boost pressure (~8-10 psi) compared to the 13B-REW (~10-12 psi), contributing to its lower peak horsepower rating. The conservative tune was designed for the Cosmo's luxury GT character rather than sports car aggression .

• Luxury Tune: The 13B-RE's power curve is biased toward low-end and mid-range torque rather than high-RPM peak power, making it smoother and more responsive in daily driving compared to the peakier 13B-REW .

• AFM-Based Fuel Management: The 13B-RE uses an Air Flow Meter (AFM) rather than a MAP sensor for fuel calculations, similar to earlier FC RX-7 turbos .

• Twin Spark Plugs per Rotor: Two iridium spark plugs (leading and trailing) per rotor chamber ensure complete combustion across the rotary's long flame front.

• Engine Weight: Complete engine assembly weighs approximately 148 kg (326 lbs), similar to the 13B-REW .

• Factory-Matched ECU Tune: The automatic transmission is fully integrated with the engine's ECU, including shift timing that complements the rotary's powerband.

• Lockup Torque Converter: Improves fuel efficiency and reduces heat generation during highway cruising.

• 4.300 Final Drive: Relatively short gearing that keeps the rotary engine in its optimal power range.

• 1x Mazda 13B-RE Longblock (Complete 2-rotor assembly with rotor housings, side housings, and irons)

• 1x Intake Manifold with large-port runners

• 1x Twin-Turbo System (HT-10 primary, HT-15 secondary – sequential configuration)

• 1x Cast Iron Exhaust Manifolds

• 1x 4-Speed Automatic Transmission with torque converter

• 1x Engine Wiring Harness (if included – specify Cosmo donor year)

• ECU, alternator, starter, ignition components, and accessories.