Mazda MX-5 Miata NB Roadster Coupe 1.6-Litre DOHC Engine
The 125 PS 1.6-litre engine application in the Japanese base Roadster Coupe, derived from the 1600SP.
Engine application
The base Mazda Roadster Coupe used a nominal 1.6-litre inline-four with double overhead camshafts, rated at 125 PS and coupled to a five-speed manual driving the rear wheels. Mazda identified the 1600SP as its donor grade. Customer-order availability in Japan was announced on 9 October 2003; this is a calendar date, not an export model-year designation. Mazda launch release.
Engineering and production context
Mazda’s technical account states that the Coupe retained its donor Roadster’s powertrain and chassis. Development followed the RS Coupe concept shown at the January 2002 Tokyo Auto Salon. The production programme combined Mazda’s regular manufacturing processes with Mazda Engineering & Technology’s specialist body assembly, allowing a dedicated closed body to use established mechanical components.
The Japanese production process involved transferring platforms and shared parts to Mazda E&T for body construction, then returning completed bodies for normal painting and vehicle assembly. This describes vehicle manufacture, not the engine’s assembly plant. Historically, the application illustrates how the NB’s existing smaller engine supported a specialist two-seat coupe programme. Mazda Technical Review, pp. 103–105.
Grade distinctions and evidence limits
The 1.6-litre specification belongs to the base Coupe. Type S, Type A and Type E used 1.8-litre engines; their ratings and transmissions do not describe this application. Mazda grade specifications.
The cited documents do not establish this engine application’s code, complete production interval, actual production total or engine assembly location. Those details remain unverified.
For the related open-car application, see the Japanese SP 1.6-litre DOHC engine.