What are people doing with brake cooling?

[Ginger_Extract]

In general, anything related to "cooling" seems to be an issue with this car, but right now, let's talk brake cooling. Has anyone figured out a good solution?

Running Hawk DTC70/60, and performance is solid, but after each 20 minute session, at the end of the cool down lap, the pedal goes straight to the floor every time, upon slowing to re-enter the paddock. I have been facilitating this by "touring" the car through the paddock for a few minutes for the sake of circulation and heat extraction. Brake force always comes back for the next session, but that to me indicates insufficient temperature control, and likely premature brake destruction. Boiling the brake fluid at every event is not cool.

Pad wear always appears even, and at least for now, not dangerously rapid, but a more effective solution, there surely must be... So 1Addicts, please post up what has/has not worked for you thus far!

[1&done]

I was just at Sebring over the weekend and only had moderate brake fade once during a session. I was running the F2500s to see how they would hold up. Never had an issue with my Carbotechs. You might want to try ducting. Also I use the F-body brake dust shield, I suppose it helps a little, and titanium shims.

[dcaron9999]

Originally Posted by 1&done

I was just at Sebring over the weekend and only had moderate brake fade once during a session. I was running the F2500s to see how they would hold up. Never had an issue with my Carbotechs. You might want to try ducting. Also I use the F-body brake dust shield, I suppose it helps a little, and titanium shims.

Just installed F series brake dust shields myself. Bought Hardbrakes Titanium Heat Shields last summer. Will be installing Carbotech XP10 pads soon. First set of endurance brake pads for me since I started lapping.

Ran into boiling fluid situation with stock fluid once, and ended up with soft pedal. Been running Motul RBF600 fluid since then, on Extreme performance tires, with no more boiling/soft pedal issues.

[fe1rx]

Originally Posted by Ginger_Extract

Running Hawk DTC70/60, and performance is solid, but after each 20 minute session, at the end of the cool down lap, the pedal goes straight to the floor every time, upon slowing to re-enter the paddock. I have been facilitating this by "touring" the car through the paddock for a few minutes for the sake of circulation and heat extraction. Brake force always comes back for the next session, but that to me indicates insufficient temperature control, and likely premature brake destruction. Boiling the brake fluid at every event is not cool.

The pedal to the floor is a fluid issue. In my experience, fluid, once cooked is never quite right again. I am glad that the DTC combination works well because I am going to try that this year myself.

It sounds like while you are running on the track there is just enough air flow to keep the caliper bodies cool enough to have the fluid survive but as soon as you slow down the heat from the rotor soaks into the caliper and the fluid. With the DTC pads you can potentially have gotten your front rotors glowing hot on the track without fading the pads.

Titanium shims may help a bit, but they reduce one heat flow path for the pads so your pads will run hotter. On my previous race car I ran a titanium shim on my front pads (to help save the piston boots, which they did) and had bulletproof performance. Thinking one shim good, two shims better, I tried two and immediately started getting pad fade because the pads were operating hotter with two shims.

Same car, I tried numerous fluids, and all but one of them started feeling a bit off after a weekend, and immediately if there was an incident that stopped the track with full heat in the brakes. Clearly that was another car that ran its brakes hot and I ended up doing a fluid flush after every weekend to keep good pedal feel.

The one fluid that worked flawlessly and lasted a complete season was Castrol SRF. I ran several seasons with just a single pre-season fluid flush with SRF. I am switching to that this season on the 1 and hoping for the best once again because I know my brake temperatures will go up significantly with the DTC pads.

In any case, once you get fluid fade (pedal getting soft and going to the floor), you really should flush the fluid, even if the pedal feel seems to come back.

[Kgolf31]

Fading pad would be a brake pad that had solid pedal feel but simply wouldn't brake.

Pedal going to the floor is a fluid issue.

[Ginger_Extract]

- To further elaborate, I have bent back the stock splash shields and use HardBrake shims up front, OEM shim in the rear.

- Have tried RBF600 and the tried and true ATE Typ200, it's much of a muchness between the two. Have read about the Castrol SRF, but opinion is mixed on it. Will be curious to hear about it specifically in use with the E82 and the OE Brembos.

- Ducting is my thought as well, but the lack of bolt up and go kits, means this is going to take time to prototype a setup and figure things out.

- The DTC70/60 will create/handle a TON of friciton. Until I had put some hard miles on the rotors, I was throwing sparks everywhere.

[AB M2C]

I think ducting is definitely your best option. Honestly it shouldn't be too hard to fab up something like this:

http://www.m3post.com/forums/showthread.php?t=316897

You could also try upping to a higher temp DOT 5.0 break fluid.

[PrematureApex]

DOT 5.1 is compatible with your stock fill, or the other fluids mentioned, not the silicon-based DOT 5.

OP, you positive it's boiling fluid vs. pad knockback or something else? Agreed it's ceratinly not pad fade (that block-of-wood- feel). Just happens after your cool-down lap when pulling in?

[02rsxpilot]

I have to agree with Kgolf. Sounds like textbook brake fluid boiling.

Personally, I've never heard of folks using ducting or shims or any of that in an effort to keep brake fluid cooler. Those steps are usually an attempt to keep rotors and pads cooler (which I suppose might have an indirect effect on brake fluid temps).

I'd propose a few solutions to try:

1) Flush fluid right before a track day. Continue to use any of the DOT4 options, because they should all be sufficient for standard HPDE driving, theoretically.

2) IIRC, in descending order of highest boiling point: Castrol SRF, Motul RBF660, Motul RBF600, ATE 200. Keep trying higher and higher until you find something that doesn't boil.

Or as a last resort because it requires an ego check,

3) Evaluate your braking habits on the track. The fluids above are designed for race tracks, so if you're still boiling them, it isn't the fluid, and it isn't the car, so it's probably the driver. The tracks in SoCal can be scorching so sometimes you have to adjust your driving habits for that particular day and track. The ability to adapt to the track and car conditions is a major part of what separates great drivers from mediocre ones. I'd ride with someone else that day, someone fast in a similar car, and pay special attention to where and how hard they brake.

Definitely let us know if you get it solved!

[Ginger_Extract]

Originally Posted by 02rsxpilot

I have to agree with Kgolf. Sounds like textbook brake fluid boiling.

Personally, I've never heard of folks using ducting or shims or any of that in an effort to keep brake fluid cooler. Those steps are usually an attempt to keep rotors and pads cooler (which I suppose might have an indirect effect on brake fluid temps).

I'd propose a few solutions to try:

1) Flush fluid right before a track day. Continue to use any of the DOT4 options, because they should all be sufficient for standard HPDE driving, theoretically.

2) IIRC, in descending order of highest boiling point: Castrol SRF, Motul RBF660, Motul RBF600, ATE 200. Keep trying higher and higher until you find something that doesn't boil.

Or as a last resort because it requires an ego check,

3) Evaluate your braking habits on the track. The fluids above are designed for race tracks, so if you're still boiling them, it isn't the fluid, and it isn't the car, so it's probably the driver. The tracks in SoCal can be scorching so sometimes you have to adjust your driving habits for that particular day and track. The ability to adapt to the track and car conditions is a major part of what separates great drivers from mediocre ones. I'd ride with someone else that day, someone fast in a similar car, and pay special attention to where and how hard they brake.

Definitely let us know if you get it solved!

Good sentiments to keep in mind, thanks. I did bleed the fluid quite literally the day before the event w/ fresh, sealed, Typ200.

In regards to my (lack of) driving talent, upon reviewing my in-car footage, my braking actions are as succinct and to the point as I remember them being. Enough brake force just short of ABS threshold, for the most part, and no excess brake dragging. So, IMO, technique isn't the problem (for once!).

[02rsxpilot]

Yeah, I'd probably start going up the fluid chain then. At least the problem happens on your cool down and not during the session.

If the problem persists, there are some great books out there on racing (I'm partial to Ross Bentley's Speed Secrets) that might give you an insight or two that helps you not necessarily with how you brake, but how much. One of my favorites from him is his emphasis on being smooth. He says if a blind/blindfolded person rode with you, they shouldn't be able to feel your transitions between braking and accelerating . That's a whole 'nother level of smooth!