What is the Mazda R100?

The R100 is the export name for the Mazda Familia Rotary Coupe, produced from 1968 to 1973. It was the first mass-market car to use Mazda's 10A twin-rotor Wankel engine, the same fundamental engine type as the Cosmo Sport, but in an affordable, lightweight coupe body. The R100 weighed approximately 850 kg, produced around 100-110 horsepower from its 982cc twin-rotor, and was sold in Australia from 1969.

The R100 is best known in Australia for its class victory at Bathurst in 1969, which introduced the Australian public to rotary-powered cars and launched the rotary culture that thrives to this day.

What engine does the R100 have?

The R100 uses the Mazda 10A twin-rotor Wankel engine. Key specifications:

• Displacement: 982cc (491cc per rotor chamber)
• Configuration: Twin-rotor, peripheral exhaust ports
• Power: Approximately 100-110 hp (73-81 kW) at 7,000 rpm
• Torque: Approximately 130 Nm at 3,500 rpm
• Fuel system: Single carburettor (Hitachi or Nikki)
• Redline: 7,000 rpm

The 10A is the smallest and earliest production twin-rotor Mazda engine. It uses 2mm-wide apex seals (compared to 3mm on the later 12A and 13B) and has a reputation for being less durable than its successors. However, when properly maintained and rebuilt with quality parts, the 10A is a willing, characterful engine that rewards high RPM and revs with a sound unlike anything else on the road.

Did the R100 really race at Bathurst?

Yes, and that is central to its significance. In 1969, Mazda Australia entered a team of R100 coupes in the Hardie Ferodo 500 at Mount Panorama. They won their class, competing against a field that included V8-powered Holden Monaros and Ford Falcons. The R100s were dramatically faster than their sub-litre displacement suggested, and their high-revving rotary engines produced a turbine-like sound that was completely new to the Bathurst crowd.

The 1969 class win led directly to Mazda's expanded motorsport programme with the RX-3, which won the Bathurst 1000 outright in 1972. The R100 was the opening chapter.

How many R100s were sold in Australia?

Exact Australian sales figures are difficult to confirm, but the R100 was sold in modest numbers, likely in the low thousands across its 1969-1973 Australian sales period. It was a niche product in a market dominated by the Holden Torana, Ford Cortina, and Datsun 1600. The rotary engine was a selling point for enthusiasts but a concern for mainstream buyers unfamiliar with the technology.

Survival rates are low. Many R100s were used in motorsport, modified beyond recognition, or scrapped when their engines wore out. Clean, original examples are now genuinely rare.

What is the difference between the R100 and the RX-2?

The RX-2 (Mazda Capella Rotary, 1970-1978) was a larger, more refined car than the R100. Key differences:

• Engine: The RX-2 used the 12A twin-rotor (1,146cc), while the R100 used the smaller 10A (982cc).
• Size: The RX-2 was a larger car, more interior space, more boot space, more comfortable.
• Refinement: The RX-2 had better NVH, more equipment, and a more conventional family car feel.
• Performance: The 12A in the RX-2 produced more power and torque, with better durability thanks to wider apex seals.

The R100 is the raw, lightweight, no-frills rotary. The RX-2 is the next step up in size and refinement. Both are desirable, but the R100's Bathurst pedigree and featherweight character give it a unique appeal.

How much does an R100 cost in Australia?

In 2026, expect to pay:

• Project car (needs work, may have rust): $30,000-45,000 AUD
• Running, presentable condition: $45,000-65,000 AUD
• Excellent, original, documented: $65,000-80,000+ AUD
• Competition history / Bathurst provenance: $80,000-120,000+ AUD

Cars with 12A or 13B engine swaps are cheaper, $15,000-45,000 depending on condition and quality of the build. Original 10A cars command a significant premium.

Should I buy an R100 with the original 10A or a 12A/13B swap?

It depends on what you want.

Original 10A: The purist's choice. Historically correct, period-appropriate sound, and maximum value retention. The 10A is less powerful and less reliable than the 12A or 13B, and parts are harder to source. Choose this if originality, heritage, and concours eligibility matter to you.

12A swap: The pragmatic upgrade. The 12A is a direct evolution of the 10A, same twin-rotor layout, larger displacement (1,146cc), wider apex seals, and significantly better durability. It was the engine in the RX-3, making it arguably period-correct for an early 1970s Mazda. A 12A-powered R100 is a faster, more reliable, and more maintainable car. This is the choice for people who want to drive the car regularly.

13B swap: Maximum performance. The 13B (1,308cc, available naturally aspirated or turbocharged) transforms the R100 into a genuinely fast car. However, the 13B is heavier and wider than the 10A/12A, may require driveline modifications, and changes the car's character significantly. This is the choice for track use or a street/strip build.

What fuel does the R100 use?

Premium unleaded, 98 RON. The 10A's compression ratio and combustion characteristics require high-octane fuel. Avoid E10 or higher-ethanol blends unless the fuel system has been upgraded with ethanol-compatible components.

If the oil metering pump is functioning, no premix is needed (though many owners premix as additional insurance at approximately 1:200 ratio). If the pump is disconnected, premix is mandatory.

Fuel economy is approximately 13-17 L/100 km depending on driving style. Enthusiastic driving and high RPM use push consumption toward the higher end.

Where do I find parts for an R100?

Parts sourcing is one of the biggest challenges of R100 ownership:

• Rotary engine internals: Atkins Rotary (Brisbane), PAC Performance (Sydney), and Promaz (Melbourne) stock 10A, 12A, and 13B parts. Some 10A components are shared with the Cosmo Sport and RX-2.
• Body panels: Not reproduced. Source from wreckers (increasingly rare), import from Japan (Yahoo Auctions Japan), or have fabricated by a panel beater.
• Suspension and brakes: Cross-reference with later Mazda models. Some components from the RX-2 and RX-3 interchange.
• Interior trim: NOS from Japan, used from wreckers, or custom retrimmed.
• Weatherstripping and seals: Some universal kits can be adapted; original Mazda parts are essentially unavailable.

Join the Rotary Engine Club of Australia and the online rotary communities (AusRotary, RX7Club.com). The network of enthusiasts is your most valuable parts-sourcing resource.

Is the R100 a good first classic car?

Honestly, no. The R100 demands specialist knowledge (rotary engines are fundamentally different from piston engines), specialist tools (rotary compression tester), specialist mechanics (not every workshop understands rotaries), and a tolerance for parts scarcity. It is also expensive to maintain and restore.

If you are drawn to rotary cars, start with an RX-7 (FB or FC), they are more available, better supported by the parts ecosystem, and more forgiving of beginner mistakes. Once you understand the rotary engine and have built relationships with specialists, the R100 becomes a realistic proposition.

How do I register an R100 in Australia?

If the car was originally sold in Australia, it will have an Australian compliance plate and can be registered normally (subject to passing a roadworthy inspection in your state). If the car has been imported, it will need SEVS (Specialist and Enthusiast Vehicle Scheme) approval and compliance.

Most surviving Australian-delivered R100s will have lapsed registration. The process for re-registering varies by state but generally requires a roadworthy certificate (RWC/pink slip) and proof of identity (chassis number, engine number, previous registration records). Historic/club registration is available in most states and is the most cost-effective option, it limits usage to events, rallies, and approved club runs but significantly reduces registration and insurance costs.

What is the R100 like to drive?

Light, direct, and raw. The steering is unassisted, the brakes require commitment, and the suspension communicates every road surface through the seat. The 10A engine revs freely and makes its power at high RPM, below 3,000 rpm, the car feels modest; above 5,000 rpm, it comes alive. The exhaust note is a distinctive rotary wail that builds intensity as the revs climb.

By modern standards, the R100 is slow in a straight line (0-100 km/h in around 10-11 seconds) but feels much faster than the numbers suggest because of its low weight, its directness, and the way the engine begs to be wrung out. It is a car that rewards involvement, you must work the gearbox, plan your braking, and commit to corners. It is the antithesis of a modern assisted driving experience, and that is precisely the point.