Since I began attending HPDE track events, I have used SRF. It seems to be impossible to find. What are you using as alternatives? I'm considering Endless RF 650, but Motul 660 is less than half the price...cost is not the big consideration, but is Endless worth the premium price? TIA
Thanks for the feedback. Do you change fluid after each track day? With SRF I would change annually, attending 4 track day sessions each summer.
Thanks! Do you recommend to change after each track session (4 runs of around 40 minutes each) or every other? Definitely going back to SRF when available.
If you are not overheating it shouldn't be required. SRF has the best water absorption abilities out there.
We use SRF in a Daytona for track events, worth it for safety. Not sure what additives they use to get the boiling point up, but the SRF and Motul 660 gets past my seals just a bit. We use Motul 600 or Ate Blue in our race cars.....as long as we bleed often we don't have any problems with the 600/Ate. As I'm sure you know, that brake fluid absorbs moisture as it ages, with a boiling point of 212F.
If your brake system isn't marginal then you don't need the expensive srf. I'm lazy so I want to do the least work. Changing fluid often isn't what i want to do with all the other race prep and development needs. I want to be able to use any off the shelf fluid and that means have heat capacity in the system and right sized cooling ducts and right shaped spindle ducts etc.
It's a standard 430 spider. Steel brakes with Carbotech pads, per your recommendation. Sent from my Galaxy
If you can get away with ATE you can use just about anything. It is a pretty ordinary fluid and nowhere near the heat abilities of the Motul. Just means it has great brakes that are not being over driven. A Daytona on the other hand is a great car to test fluids in. By modern standards it is very under braked. I used a clients Daytona at Laguna Seca a number of years ago to test brake fluids. Laguna is a very brake intensive track and we only had to go a few laps to know how different brake fliuds performed. The worst we tested was ATE. Yes most fluids are hydroscopic but I have read and not confirmed SRF is actually hydrophobic like silicone and is why it has such excellent wet specifications. We also know hydrophobic or not brake fluid gets water in it.
SRF for me feels more compressible and it leaks past the caliper bleed screws. I have had better experience with Motul RBF660. Endless also has great fluid too that some of track friends use
I’ve been using endless in my challenge car. Brakes glow red hot... never had an issue and able to run a whole day and not have to bleed. For high heat, I’ve been very happy with it.
SRF should be available soon, I just ordered 3 bottles. Interesting that leakage was noted past the caliper bleed screws, I had the same issue near the end of a session and my brakes felt a little soft on my GT3, never on my Cayman. Since I am in the process of doing all annual maintenance on my 458, switched to Motul 660.
SRF is expensive but not when you consider the damage caused by brake failure. Motul 660 is something to use if you can't find SRF, but they are not equal. Changing brake fluid is extremely important as it is hygroscopic - it absorbs moisture. Moisture gets into brake systems and that moisture boils and causes a lot of brake fade. Even if you buy SRF it won't save you if you don't change your fluid regularly.
You can just bleed some (not all) of your fluid at the caliper bleeders after each track session. I do 4 brake pedal pumps in front and three in back out of each of the two bleeders per corner. The fluid gets hot by the caliper, not all the way up the line. I do quite a few track days and if a light brake use weekend due to easy or wet track, I will bleed the next time. Motul 660.
Endless is the way to go. Great stuff. In the exige track car I change it every 5 days to playboy safe. In the Elise which is sued as a toad car and does maybe 3-4 track days I do it seasonally. srf felt too spongy to me
SRF is the the best hands down. Motul Is very very good but not quite as high of a “wet” boiling point. Brake fluid by itself cannot feel spongy, it is (as all brake fluid is) non-compressible. Lots of other parts can contribute to a spongy feel (pads, brake lines, air in the lines etc.). All brake fluid is the same until it boils, that what makes SRF the best, very high “wet” boiling point. All DOT 4 will absorb water fairly quickly, read the specs if you are comparing different fluids. YMMV.
Brake fluids have different feels. SRF is a great fluid but is known and tested to prove it is more compressible that other fluids. That is why I mentioned SRF feels spongy to me. Here is some tested data on this among other data points. https://thebuildjournal.com/tech-guides/ultimate-brake-fluids-review-analysis/ https://parsbrorc.com/?page_id=33
Great article and thanks for posting, as a “lazy” track guy the SRF is the best of the group. I always reserve the right to get smarter and will check out the Endless fluid. I am also intrigued how they measure compressibility and at what temperature, it should be negligent in a braking system but I have been wrong before.