The Mazda Roadpacer AP is a full-size sedan that was sold by Mazda Motor Corp. of Japan between 1975 and 1977. It was based on the Australian Holden HJ and HX series Premier. Premiers were shipped to Japan without engines, and Mazda fitted a 1.3-liter 13B Wankel engine into the bay. Although the engine produced 100 kilowatts (130 hp) and 138 newton metres (102 lb·ft) of torque, the Roadpacer weighed 1,575 kilograms (3,470 lb).
While the 13B produced more power than the Red series motors that powered the equivalent Holdens, the lack of torque meant performance was restrained with a 166-kilometre-per-hour (103 mph) top speed, poor acceleration and terrible fuel consumption. Contemporary reports suggest 9 mpg (26 L per 100 km).
While the Holden HJ Premier itself was well equipped, Mazda decided to add more. Gadgets of note include a central locking system that activated when the car hit 10 km/h (6.2 mph), a chime system that activated at 90 km/h (56 mph), a dictation system and a stereo able to be controlled from both front and back seats.
The price was also considered high at 3.8 million yen (US$10,000) in 1975. This was about twice the price of a contemporary Mazda Cosmo. Originally intended as transport for high-ranking government officials, the car was sold in the wake of the first fuel crisis and was not a commercial success. Production ceased in 1977 with only 800 units sold.
The Roadpacer has the sole distinction of a General Motors product being fitted for production with a rotary engine.
Most were sold to government departments and were later crushed, meaning Roadpacers are rare nowadays; their counterpart model, the Holden Premier is considered a classic car in Australia.