Fatsix

What do you guys think about Castrol SRF, Endless RF650 or the new Motul RBF700? All three seems to have great high heat performance. I am wondering which has the most longevity so I wouldn't have to change it out as often.

Quadcammer

Any are fine and all are overkill for streer use. I change srf yearly on track car

Petza914

I thought the benefit of SRF is that it didn't need to be changed yearly and why the higher price over RBF.

Fatsix

I am looking for street and track use fluid that needs less frequent changes. I read that people use Endless for over a year on track cars as well. So I’ll cross out RBF.

ADias

What's wrong with ATE SL DOT 4? It lasts at least 2 years and it's the OEM product.

ATE has a higher temp version too.

Bruce In Philly

2009 C2S 186K miles

Back when I was going to the track, one of the requirements was that brake fluid can't be more than 30 days old... one guy at tech inspection had a tester. Something to consider. Further, I used the OEM stuff... usually ATE... and never had boiling. Porsche has it correct.

Peace
Bruce in Philly (now Atlanta)

Fatsix

I boiled Ate at Willow Spring. after running for half a day, fluid leaked out of the front Brembo nipples and my day was over. I don’t ever want to have that happen again.

JRitt@essex

Your best bet is to focus on choosing a brake fluid that has a dry boiling point high enough to handle what you're planning to throw at it on the racetrack. With modern brake systems, wet boiling point is no longer as relevant as it once was. Today's systems just don't absorb as much water, as rapidly, as they once did. Also, fluids with a high wet boiling point don't always necessarily offer the best pedal feel due to their chemical composition. I can't tell you how many times we've switched a professional racing driver away from SRF and over to AP Racing and had them instantly tell us how much better their brake pedal feel was.

When you're running any brake fluid on-track, you're breaking the fluid down in numerous ways. It's not just absorbing water...it's lubricity is being altered, as its ability to act as a preservative for the brake system (prevent corrosion, etc.). In summary, you need to change your fluid as often as necessary based on the demands you're placing on it. Those demands are dictated by your car's performance, how/where the car is being used and in what manner, and even how you are driving it. Someone running their car on slicks with an additional 200 HP, on a tough braking track like Watkins Glen is going to break their fluid down more quickly than someone daily driving on street tires. Using a timeline of one year, two months, etc. is an arbitrary way of looking at the situation. It just needs to be done when it needs to be done and the fluid has degraded to the point at which performance has been negatively impacted. The situation with brake fluid is the same as tires...tires degrade over time. You replace them when they get really old, they lose grip, they no longer feel good, your lap times go down, or the internal belts are visible/hanging out. Unfortunately, the status of brake fluid is much tougher to gauge...no belts to be seen!

We (Essex) recommend AP Racing and Ferodo Racing brake fluids. We currently supply brake fluid directly to NASCAR Cup, IMSA, and IndyCar teams, club racers, HPDE drivers, etc. AP Raciing R3 was the gold standard for quite a long time, and now many teams in the elite racing series use AP Racing R4. The AP Racing range in particular has something for every need and budget. For many HPDE drivers, the AP Racing Rad-CAL R2 is the best bang-for-the-buck. It has a high enough dry boiling point to handle what many HPDE guys throw at it, without breaking the bank. We also keep thousands of bottles on the shelf and ready to ship from our Charlotte, NC warehouse at all times, so it's there when you need it most.

You can see the AP and Ferodo fluids here: https://www.essexparts.com/brake-hydraulics