Track Day Brake Fluids?

[David Inc.]

For the past many years I've been using Motul RBF 600 for my car for track days, and it's good enough (along with the Hawk HP+ pads and cooling ducts), but since I've been using it since maybe 2014 I figured by now there would be something else that's better? Any suggestions from the brain trust?

[Bill Verburg]

Originally Posted by David Inc.

For the past many years I've been using Motul RBF 600 for my car for track days, and it's good enough (along with the Hawk HP+ pads and cooling ducts), but since I've been using it since maybe 2014 I figured by now there would be something else that's better? Any suggestions from the brain trust?

If it ain't broke don't fix it

yes there are fluids w/ higher boiling points both wet and dry,
wet/dry °F

Castrol SRF 518/608
Torque RT700 439/683
Wilwood XR 432/645
Project Mu 430/635
Endless RF650 424/622

are the top 5, wet is the more important #

for comparison
Motul RBF 600 401/594
Motul RBF 700 401/635
Motul RBF 660 400/617

ATE 200 388/536

these are all type 4

[David Inc.]

For a car that gets annual brake fluid flushes, do you still think the wet boiling point is more important?

And no it's not broken, but if I can get a bit more safety margin with just a fluid flush I'm happy.

[HarryD]

To my way of thinking, once you are in this class of brake fluids, more important is pad thickness. The thicker the pad, the less heat transfer to the caliper.

Just one guys opinion.

[David Inc.]

Originally Posted by HarryD

To my way of thinking, once you are in this class of brake fluids, more important is pad thickness. The thicker the pad, the less heat transfer to the caliper.

Just one guys opinion.

I've seen that mentioned and I'm watching for that as well, thanks.

This is really just a "I have to buy some more fluid, should I stick with what I've got or change over?" kind of thread. Also for general jibber-jabber since I couldn't find a recent brake fluid thread.

Anybody know what separates the DOT 4 and non-DOT approved "DOT 4" fluids? Anything about these "off-road use only" fluids that's actually not good for the street, or is it one of those "we don't make a lot of it so the certification isn't worth the effort" situations?

[Bill Verburg]

Originally Posted by David Inc.

For a car that gets annual brake fluid flushes, do you still think the wet boiling point is more important?

And no it's not broken, but if I can get a bit more safety margin with just a fluid flush I'm happy.

No

as mentioned when the pads get to 50% retire them from track usage

All brake systems aren't stressed to the same point, there are many variables from the rotor and pad spec to the weight of the vehicle to the speed potential of the vehicle to the track configuration to the length of the sessions to the drivers idiosyncrasies etc.

examples my '76 C3 could go through a set of pads in 1 day at LRP back when I first started doing track days, my 993 RS was fine w/ ATE 200 untill the pads got to 50% and I had to hold on a slight hil in the pits during a black flag at WGI.

911 brakes were mostly fine in the early '70s w/ a skilled driver but became more and more stressed over the years as weigh and power were added to the mix.

Besides boiling fluid there are other indicators of stress such as bluing due to rotor hotspots.



Here's a comparison of some brake stress relations

[PeteKz]

Higher boiling point is good to have, but most important is to change the fluid frequently, to get the moisture out.

[Matt Monson]

You’re fine. Don’t change a thing.

[David Inc.]

Too late I bought Castrol SRF. Haha

I'll see how it feels, only slightly more expensive than the Motul.

[winders]

Brembo HTC 64T Is the best I ever used. I tried Endless and Castro SRF but the Brembo had the best pedal feel and least fade in race conditions.

I got turned on the stuff by a race engineer at a super high level IMSA race team (I can’t name either).

[Bill Verburg]

Originally Posted by winders

Brembo HTC 64T Is the best I ever used. I tried Endless and Castro SRF but the Brembo had the best pedal feel and least fade in race conditions.

I got turned on the stuff by a race engineer at a super high level IMSA race team (I can’t name either).

Brembo HTC 64T is right up there w/ the best for dry boing @635F but a few caveats
it is incompatible w/ mg parts, usually not a problem
Brembo specifically says not for street use which is partially why they don't report wet boiling point as they expect the fluid to be changed for each event usage

there are other factors that are less measurable such as viscosity, again not usually a problem and compressibility which only becomes an issue at the extreme edge of the envelope.

[winders]

Originally Posted by Bill Verburg

Brembo HTC 64T is right up there w/ the best for dry boing @635F but a few caveats
it is incompatible w/ mg parts, usually not a problem
Brembo specifically says not for street use which is partially why they don't report wet boiling point as they expect the fluid to be changed for each event usage

there are other factors that are less measurable such as viscosity, again not usually a problem and compressibility which only becomes an issue at the extreme edge of the envelope.

I ran it for 6 months at a time without changing it with zero issues with differences in pedal feel or performance. I changed it only as a precautionary measure and not because I felt like it needed to be changed.

Like I said, it was the best performing brake fluid I ever used in my race car.

[Bill Verburg]

Originally Posted by winders

I ran it for 6 months at a time without changing it with zero issues with differences in pedal feel or performance. I changed it only as a precautionary measure and not because I felt like it needed to be changed.

Like I said, it was the best performing brake fluid I ever used in my race car.

Great for you
nevertheless, Brembo HTC 64T is going to be comparable in price and performance to any of the other high end dot 4s and the rest of us mere mortals won't be able to detect any difference between them

Here's a survey of most of the top 29 rated wet BP brake fluids that would be of interest to mere mortals,

[Bill Verburg]

Here are the ones that don't report wet BP

[David Inc.]

How the heck does Castrol have such a high wet BP compared to practically everyone else? I assume magic?

[Bill Verburg]

Originally Posted by David Inc.

How the heck does Castrol have such a high wet BP compared to practically everyone else? I assume magic?

Dunno,
they have 2 other b/f lines too
Super DoT4 @365/507
DoT 4 @329/509

[ard]

Lots of good info from people who know whereof they speak in this thread already. I'll just mention that Grassroots Motorsports periodically publishes an exhaustive list of brake fluids and their properties. I don't believe they do any testing so think of the list as a "PSA". It usually appears 2 or 3 times per year in their magazine.

[Jeff Alton]

There are only so many brake fluid manufactures, but plenty of products on the market. Some are unique fluids, and some are going to be the same fluid in a different bottle.....

[Jeff Alton]

Bill, You mention compressability. Which is a thing for sure. Have you ever seen results of these HP Fluids being tested for that? I have looked, but have not found any data. It would be interesting to see how each performed as it would impact pedal feel, to a degree...

Cheers

[David Inc.]

Originally Posted by Jeff Alton

Bill, You mention compressability. Which is a thing for sure. Have you ever seen results of these HP Fluids being tested for that? I have looked, but have not found any data. It would be interesting to see how each performed as it would impact pedal feel, to a degree...

Cheers

This was one I hadn't really thought about before, but I saw a mention that the Motul was much softer than the SRF--I guess I'll see.