How much does a Scoot four-rotor conversion cost for a Mazda RX-7 FD?

A Scoot four-rotor conversion for an FD RX-7 typically costs between $15,000 (full DIY labor starting from a rolling chassis) and $35,000–$50,000+ (a complete naturally aspirated build with shop labor), with a fully built engine sourced from custom builders running about $26,000 on its own ². The Scoot 4-rotor produces around 400 horsepower and is uniquely able to run the stock FD transmission due to its linear torque delivery at that power level ².

If you are planning a 4-rotor build for your FD, this is an Expert level project that requires heavy custom fabrication. Here is a breakdown of what you can generally expect to spend:

• The Engine: A fully built 4-rotor engine sourced from custom builders (such as those in New Zealand) runs about $26,000. If you are building it yourself, a custom 4-rotor eccentric shaft/crank kit alone typically costs between $8,000 and $9,000 ².
• DIY Approach: If you handle 100% of the labor yourself—including all custom fabrication, tuning, and engine assembly—and start with a rolling chassis, it is possible to complete the build for $15,000 to $25,000 ².
• Complete Build: Once you factor in the engine, a standalone fuel management system, custom intake and exhaust fabrication, subframe modifications, and labor from a shop, a complete naturally aspirated 4-rotor build is estimated to cost between $35,000 and $50,000+ ².

While the stock transmission holds up to the ~400hp Scoot build, higher-horsepower 4-rotor setups (600+ hp) will require serious drivetrain upgrades, such as a built Tremec T56 transmission and a Ford 9-inch rear end, which will further increase the total cost ².