Motul RBF 660 Factory Line – DOT 4 Synthetic Racing Brake Fluid for Track and Motorsport

Motul RBF 660 Factory Line is a 100% synthetic DOT 4 brake fluid engineered for extreme motorsport conditions – long stints, high brake temperatures, carbon or ceramic rotors and aggressive cooling setups. Its exceptionally high dry boiling point of 325 °C / 617 °F and wet boiling point of 205 °C / 401 °F ensure consistent braking and pedal feel during intense and repeated braking phases.

Key Advantages

• Maximum thermal stability: 325 °C (dry) / 205 °C (wet) minimizes vapor-lock and brake fade during long stints and endurance racing.
• Stable performance in humid environments: maintains efficiency even after moisture absorption (~3 % H₂O), representing one year of real-world use.
• Track-focused formulation: designed for systems exposed to extreme heat, including carbon and ceramic brakes; helps reduce the need for cooling air scoops, improving aerodynamics.
• Full system compatibility: suitable for hydraulic brake and clutch systems, including modern ABS / ESP setups.

Applications – Motorsport, Endurance and JDM Performance

Ideal for performance-oriented Japanese and racing cars such as Honda (Civic Type R, Integra, S2000), Subaru (Impreza WRX / STI, BRZ), Mitsubishi (Lancer Evolution), and Nissan (370Z, GT-R clutch hydraulics). Perfect for time-attack, endurance and sprint racing, and for high-performance street/track builds requiring stable braking under repeated high loads.

Technical Specifications (Motul Official Data)

• Standard / Specification: FMVSS 116 DOT 4; SAE J1703 / J1704
• Dry boiling point: 325 °C / 617 °F
• Wet boiling point: 205 °C / 401 °F
• Kinematic viscosity @ 100 °C: 2.6 mm²/s
• Kinematic viscosity @ −40 °C: 1 698 mm²/s
• Type: 100 % synthetic polyglycol, non-silicone – amber color

RBF 660 exceeds DOT 3 and DOT 5.1 standards in boiling performance; only viscosity at −40 °C falls outside DOT 5.1 spec.

Comparison: Motul RBF 660 vs RBF 600

Usage & Compatibility

• Change interval: follow vehicle-manufacturer guidance; under track conditions replace every 6–12 months (or sooner under heavy use).
• Mixing: do not mix with DOT 5 (silicone) or LHM (mineral) fluids. Mix only with high-grade DOT 4 synthetic fluids if needed – for best performance, flush the system completely.
• Storage: keep sealed in original container; fluid is hygroscopic and absorbs moisture from air.

FAQ – Common Questions about Motul RBF 660

What is the difference between Motul RBF 660 and RBF 600?

RBF 660 has a higher dry boiling point (325 °C vs 312 °C) and is optimized for longer stints and carbon / ceramic brakes. Both share the same wet boiling point of 205 °C.

Is RBF 660 suitable for street use?

Yes – it’s a DOT 4 fluid fully compatible with ABS / ESP systems. However, its full potential is achieved under track and competition conditions.

How often should RBF 660 be changed?

Replace every 6–12 months for track or performance use. DOT 3 / 4 / 5.1 fluids are hygroscopic – moisture lowers the wet boiling point over time.

Can RBF 660 be mixed with other fluids?

Avoid mixing with lower-performance products. Do not mix with DOT 5 (silicone) or LHM (mineral). Best results come from a complete flush and refill.

Is RBF 660 compatible with ABS and ESP systems?

Yes – its stable viscosity and compressibility make it ideal for modern braking systems that require precise pressure control under heat.