Mazda MX-5 Miata NB Roadster Turbo 1839 cc Turbocharged Engine
Japan-market Roadster Turbo engine: an intercooled 1,839 cc DOHC four-cylinder rated at 172 PS.
Application and introduction
This engine powered the Japanese-market Roadster Turbo, within the NB generation. Mazda announced it on 24 December 2003, with Japanese sales scheduled for early February 2004. This is an announcement and sales chronology, not a verified engine production interval.
Japanese-market specification
- Configuration: water-cooled inline-four, DOHC, 16 valves.
- Displacement: 1,839 cc.
- Induction: turbocharger with intercooler.
- Compression ratio: 9.5:1.
- Maximum output: 172 PS (126 kW) at 6,000 rpm.
- Maximum torque: 209 Nm at 5,500 rpm.
- Transmission: six-speed manual.
These are Mazda’s Japanese-market figures; export Mazdaspeed ratings must not be substituted.
Engineering and significance
Mazda paired turbocharging with a dedicated radiator, iridium spark plugs and a red engine cover. Supporting changes included an upgraded clutch and transmission, reinforced drive and propeller shafts, and a torque-sensing limited-slip differential. Mazda emphasized broad torque delivery and presented the model as its first turbocharged Roadster.
Documentation boundaries
The cited announcement does not identify the engine assembly plant or establish production start and end dates. Those details remain unconfirmed here. No engine-family suffix, boost pressure or production total is assigned without additional documentation.