1999-2000 Mazda Miata MX5 1.8L Engine 6 Speed Manual Transmission JDM BP + Wiring & ECU

About this unit

Drivetrain Specifications

• Engine Family: Mazda B-Series

• Engine Code: BP-4W (NB1 Generation)

• Transmission Type: 6-Speed Manual (Close-Ratio Aisin Gearbox)

• Displacement: 1.8 Liters (1,839 cc)

• Valvetrain: DOHC 16-Valve with Solid Lifters (Non-VVT)

• Horsepower Output: Approx. 140–142 hp @ 6,500 RPM

• Torque Output: Approx. 119 lb-ft @ 5,500 RPM

• Factory Redline: 7,000 RPM

Vehicle Fitment & Swap Compatibility

This package serves as a factory replacement or highly popular upgrade layout for:

• Mazda Miata MX-5 (NB Chassis): 1999, 2000 (Direct drop-in replacement or premium 5-speed to 6-speed conversion)

Long Block & Transmission Installation Notes

TECH SUPPORT ADVISORY: Performing a complete 6-speed engine swap requires methodical layout adjustments. Review these professional mechanical guidelines before dropping the assembly in:

1. JDM Wiring & ECU Notice: The included JDM engine wiring harness and ECU are configured for Japanese right-hand drive (RHD) vehicles. The JDM ECU also lacks North American OBD-II emissions configurations and does not look for an immobilization system. If you need to pass local emissions testing, you MUST reuse your factory USDM engine wiring loom, intake manifold sensors, and USDM factory ECU.

2. EGR Valve Configurations: Japanese Domestic Market BP-4W engines often do not utilize an External Exhaust Gas Recirculation (EGR) valve or use a different configuration than North American models. Swap your original USDM intake manifold plenum and EGR hardware to avoid throwing dashboard check engine codes.

3. Upgrade Clutch Consumables: While the 1.8L block and 6-speed manual transmission casing are separated on the garage floor, put in a brand-new high-performance clutch kit, heavy-duty pressure plate, throw-out bearing, and pilot bearing. Always resurface or replace the flywheel.

4. Mandatory Engine Stand Maintenance: Take advantage of complete engine accessibility and install a fresh Water Pump, Thermostat, Front Crankshaft Seal, Rear Main Seal, and Valve Cover Gasket prior to final vehicle assembly.

5. Fluid & Timing Protocols: Refill the block using a premium 10W-30 or 5W-30 synthetic motor oil. Service the 6-speed manual transmission gearbox using specialized performance gear fluid like Redline MT-90 or Amsoil MTF to ensure slick, grind-free shifting at high RPMs.

6. Compression Tested at 180PSi

What is included

You receive exactly what is pictured. Engines are supplied as a long block assembly with the components visible in the photos. Accessories such as the alternator, starter, intake manifold or sensors are included only where you can see them on the unit, so check the photographs before ordering and ask us if anything is unclear.

Before you order

• Confirm the engine code against your own vehicle, not just the model year.
• Japanese market units can differ from the US version in intake, loom and sensors.
• Replace the timing components, water pump and seals while the unit is out. It is cheap insurance on an engine this age.
• Keep your original accessories until the swap is finished and running.