If you are looking for a high-performance brake fluid for your car, you might have come across two popular options from Motul: RBF600 and 5.1. Both of these fluids are designed to withstand high temperatures and provide reliable braking performance in various conditions. But what are the main differences between them and which one should you choose? In this article, we will compare Motul RBF600 and 5.1 in terms of their specifications, advantages, disadvantages, and suitability for different types of cars and driving styles.
What are Motul RBF600 and 5.1?
Motul RBF600 and 5.1 are synthetic brake fluids that belong to different DOT categories. DOT stands for Department of Transportation, which is the US agency that sets the standards for brake fluids. The DOT categories indicate the minimum boiling points that the fluids must meet or exceed.
Motul RBF600 is a DOT4 fluid, which means it has a minimum dry boiling point of 230°C (446°F) and a minimum wet boiling point of 155°C (311°F). However, Motul RBF600 far exceeds these requirements, as it has a dry boiling point of 312°C (593°F) and a wet boiling point of 216°C (420°F) .
Motul 5.1 is a DOT5.1 fluid, which means it has a minimum dry boiling point of 260°C (500°F) and a minimum wet boiling point of 180°C (356°F). Motul 5.1 also surpasses these requirements, as it has a dry boiling point of 272°C (521°F) and a wet boiling point of 185°C (365°F) .
The dry boiling point refers to the temperature at which the fluid starts to boil when it is fresh and free of moisture. The wet boiling point refers to the temperature at which the fluid starts to boil when it has absorbed about 3.7% of water by volume. Water can enter the brake system through microscopic pores in the hoses, seals, and reservoirs, or through condensation in humid environments.
Water lowers the boiling point of the brake fluid, which can lead to vapor formation in the brake lines when the brakes are applied repeatedly or for prolonged periods. This can cause a spongy pedal feel, reduced braking efficiency, or even complete brake failure.
Therefore, it is important to choose a brake fluid with high boiling points, especially if you drive your car hard on the road or on the track. It is also recommended to change your brake fluid regularly, at least every two years or according to your manufacturer’s specifications.
Advantages and disadvantages of Motul RBF600 and 5.1?
Both Motul RBF600 and 5.1 have their pros and cons, depending on your car’s specifications and your driving style. Here are some of the main factors to consider when choosing between them:
Motul RBF600 has higher boiling points than Motul 5.1, which means it can resist higher temperatures and prevent vapor lock more effectively. This makes it ideal for racing applications or high-performance cars that generate a lot of heat in the brakes. Motul RBF600 also has a higher viscosity than Motul 5.1 at low temperatures, which means it can provide better pedal feel and modulation . However, this also means that it may not flow as well in very cold conditions or in cars with ABS systems that require low-viscosity fluids . Motul 5.1 has lower viscosity than Motul RBF600 at low temperatures, which means it can flow better in cold conditions or in cars with ABS systems . However, this also means that it may not provide as good pedal feel and modulation as Motul RBF600 at high temperatures .
Motul RBF600 and 5.1 are both compatible with other DOT3, DOT4, and DOT5.1 fluids, which means you can mix them with your existing fluid without any issues . However, you should always flush your brake system thoroughly when changing your fluid to ensure optimal performance and avoid contamination. You should also avoid mixing different brands or types of fluids, as they may have different additives or formulations that could affect their properties.
– **Cost**: Motul RBF600 and 5.1 are both premium brake fluids that cost more than conventional DOT3 or DOT4 fluids. However, Motul RBF600 is more expensive than Motul 5.1, as it is a racing-oriented fluid that offers higher performance and durability. The price difference may vary depending on the retailer, but generally, Motul RBF600 costs about twice as much as Motul 5.1 per liter .
Which brake fluid should you choose for your car?
The choice between Motul RBF600 and 5.1 depends on your car’s specifications and your driving style. Here are some general guidelines to help you decide:
Choose Motul RBF600 if
You have a high-performance car that generates a lot of heat in the brakes, you drive your car hard on the road or on the track, you prefer a firm and consistent pedal feel, you don’t mind paying more for a premium racing fluid, and you don’t drive your car in very cold conditions or have an ABS system that requires low-viscosity fluids.
Choose Motul 5.1 if:
You have a standard or moderately tuned car that doesn’t generate excessive heat in the brakes, you drive your car normally on the road or occasionally on the track, you prefer a smooth and easy pedal feel, you want to save some money on a premium fluid, and you drive your car in cold conditions or have an ABS system that requires low-viscosity fluids.
Of course, these are not hard and fast rules, and you may find that either fluid works well for your car and your preferences. The best way to find out is to try them out yourself and see how they perform in your brake system.
Motul RBF600 and 5.1 are both high-quality brake fluids that offer excellent performance and reliability in various conditions. However, they have different characteristics that make them more suitable for different types of cars and driving styles. Motul RBF600 is a racing-oriented fluid that has higher boiling points and viscosity than Motul 5.1, making it ideal for high-performance cars that generate a lot of heat in the brakes and drivers who prefer a firm and consistent pedal feel. Motul 5.1 is a standard fluid that has lower viscosity than Motul RBF600, making it ideal for standard or moderately tuned cars that don’t generate excessive heat in the brakes and drivers who prefer a smooth and easy pedal feel.
We hope this article has helped you understand the differences between Motul RBF600 and 5.1 and choose the best brake fluid for your car. If you have any questions or feedback, please leave a comment below.
|Feature||Motul RBF600||Motul 5.1|
|DOT rating||DOT 4||DOT 5.1|
|Wet boiling point||215°C (419°F)||180°C (356°F)|
|Dry boiling point||270°C (518°F)||230°C (446°F)|
|Viscosity||1.50 mPa·s @ 20°C||1.20 mPa·s @ 20°C|
|Compatibility||Compatible with DOT 3, DOT 4, and DOT 5.1 brake fluids||Compatible with DOT 3, DOT 4, and DOT 5.1 brake fluids|
|Applications||High-performance street cars, track cars, and racing cars||High-performance street cars, track cars, and racing cars|