Using Carbon Ceramic Brakes for racing

[Kurtvette]

Hi,

Anyone out there getting track time with the carbon ceramic brake setup? If so I could sure use some input on your experience. We just switched over to that setup for the last event. We are running the car in the Optima Ultimate Street Car Challenge which combines, autocross, speed stop, and road course events for each track weekend.

We are very hard on the brakes and always looking for an edge. The carbon ceramic setup offered a significant weight savings over the traditional big brake kit we were running.

The brakes were outstanding all weekend until the last event which was the second road course session. It appears that the left side brake was no longer effective and the car pulled severely to the right. Still doing some forensics back at the shop to make sur something else in the brake system isn't at fault.

We did not a white chalky buildup on the sides of the brake pads. It would flake off easily. Is that a result of the normal bedding process or is it possible that the pads were overheated.

We were running clockwise at Portland Raceway so mostly left-hand turns.

Any thoughts or ideas would be greatly appreciated.

Thanks,
Kurt

[Mikey]

I am surprised you are running CCBs. Thought they required a good bit of heat before they reach max stopping power. Not achievable in autocross. Takes deliberate effort to warm up on road course as well.

What pad and rotor temps are you seeing?

I would talk to the engineers that recommended your setup and explain to them what you experienced and what you found upon inspection.

Also if you are running Portland clockwise, or pretty much any circuit clockwise, you are turning right more than left. But are you even trail braking that much into the corner?

[Kurtvette]

Mikey,

Thank you for the reply. These brakes actually had very good grip at lower temps. From what I have been reading it is the carbon-carbon type that need a lot of heat to work well.

Unfortunately I don't have any previous experience with either.

The car owner wanted to try them because of the weight savings so we don't have any engineering input prior to installation.

I'll search for engineering expertise as you suggest.

Thanks,
Kurt

[Cbr]

Hey - we are running auto cross and time trials. Not a whole lot of laps at a time. 3 sessions. Tires fall off hard after about two laps so it?s not a lot of track miles.

Talking with brake experts at Wilwood, Essex, etc. you get a whole lot of different opinions. Also talking with people who run them.

I figured if there was any format they would be appropriate for, this would be it.

I found a second hand set to experiment with

They worked shockingly well

Autocross fine. It was a 60-70 degree day but they were fine cold.

Track they were great for 2 hard sessions. Then the third session right out of the gate one front was just not working. Pulled hard right on braking.

Won anyway but just got it out of the trailer and so far nothing visually obvious to explain what happened.

I know these are not great for all out racing or track day cars with lots of track miles but for this app they work well, just need to troubleshoot.

Any ideas or advice is welcome. And thanks Kurt!

[Cbr]

As for Portland we ran clockwise. Big power car but small 200tw street tires Haven?t logged data yet but I?d bet we were well over 150 on both straights.

Pretty hard in 2 brake zones.

I didn?t take temps. I?ll buy some temp tape for testing.

[Mikey]

Put temp strips on the calipers and paint the edge of the rotor with temp sensitive paint. Pegasus racing is a great source for both.
Try talking with AP about what they would recommend for your application. Their technical support is outstanding. Wilwood has been more focused on street rods and the good engineers I knew there have moved on.

I suspect your chalky white pads were overheating.

[Cbr]

Diagnosis not going real well so far. Pads all look the same. Rotors too. Nothing visually obvious. Brake pressure equal at both front calipers and electronically at both abs sensors. Caliper pistons seemed a bit hard to manipulate by hand. They all move in and out under air or brake pressure though. Since it was pulling hard right I assumed the problem might have been in the lf caliper so I replaced it. The mounts were a tad too far outboard so I cut them down .040 to center them better. I noticed the rf has a tad more clearance at the bottom of the caliper than top but I do t have a great way to machine that and it?s not far off. Put it all back together and tested. Still pulling hard right. But with abs off it is actually locking the left front way bf the right. Seems counter intuitive.

Going to take another look at the rf caliper, the rears, look for something in the suspension or alignment as well. Any other ideas?

[Mikey]

Are you sure the problem is with the brakes then? And not something in the suspension or wheel causing it to pull right?