Which brake fluid should I use for high performance driving?
The one thing all brake systems have in common is that they all revolve around moving brake fluid. This is the life-blood of your braking system and even the best system with the wrong or bad fluid will not get the job done. The government (DOT) sets minimum standards for how brake fluids must perform. These standards are great for a street car or minivan, but high-performance driving means high-performance stopping, and this can overtax your run-of-the-mill brake fluid.
There are also silicone based fluids that are less hydroscopic than ether based fluids, but they are subject to "frothing" when forced through small orifices or subjected to high frequency vibration. This makes them unsuitable for high-performance or racing use.
Difference between standard and high-performance brake fluid
The main difference between standard and high-performance brake fluids is how it handles heat. The previously mentioned Castrol SRF has been tested to over 590 degrees Fahrenheit with a staggering wet boiling point of 518 degrees. At these temps your average fluid would be boiling away. It also has a low moisture affinity to slow the natural absorption rate of water vapor. As brake fluid absorbs water (hydroscopic), it becomes less effective and the temp at which it boils goes down. This is why it is important to change out your brake fluid on a regular basis and only use fresh fluid from sealed containers. The true test of any brake fluid is how well it resists aeration and compressibility after it has been heated and pressure cycled a few hundred times.
What factors degrades brake fluid effectiveness?
The three main enemies of brake fluid are heat, air and water. Water in your brake fluid will lower your effective boiling point and degrade your entire systems performance. If you have air in your brake lines this will also degrade your system since the air will compress easier than the fluid would have and thus less energy is applied to the clamping force on the rotor. This is why it is important to keep fresh high-quality fluid in your system and make sure all air is properly bled out. Also, the harder you drive your car the more often you should service (replace) your brake fluid.
So what do I need?
For a daily driver, occasional weekend sports car, hot rod, muscle car.... we have several good choices ranging from ATE TYP 200 and Castrol Advanced Performance DOT-4 to Liqui Moly DOT-4 and EBC DOT-4. These choices go for between $10.99 and $18.50 a liter and will suit your application with far better results than Autozone $6 DOT-3 fluid.
The next category would be the customer using their car for an occasional AutoCross event or a High Performance Driving Event/Trackday as well as aggressive street use. This range of the automotive spectrum requires a bit more. Brembo LCF 600, Motul 600, Wilwood EXP600+ will all suit this category well with a price point between $38.00 and $40.00 a liter.
Lastly you have the diehard AutoCross, Trackday, and true wheel to wheel racing customer... They need to look at something that performs as well as a regular maintenance schedule. While Nascar & Indy teams flush complete brakes systems with SRF every time the car hits the track surface, that is no where near what you need to do. We would recommend bleeding the fluid that is in the calipers (50ml or less in most cases) after every event or possibly after each session depending on pedal feel and how much track time the car had under hard braking conditions. At the beginning of a new season I would recommend a full flush due to moisture absorbed during the off season. For this level of abuse we come to the Castrol SRF, Motul 660, PFC 665, Brembo HTC64, and Pagid RBF626... with costs ranging from $52.00 to $70.00 a liter.
Following these recommendations will serve you well with a properly operating brake system capable of handling the abuse being thrown at it. Below is a link to the Brake Fluid section of our site and as always if you have any questions, don't hesitate to call and ask 800-733-8380.