Odd brake pedal feel, fade?

[yomny]

After a few (4-6) hot laps at my local track the cars was experiencing brake fade. What i think brake fade is, so everyone could be on the same page(correct me please if im wrong) is the build up of the binding gases of the pad between the rotor and pad, preventing braking force/bite or solid pedal feel. The event was a couple of days ago and my pedal still feels spongy and the braking force isnt adequate, at least i think it should be a lot stronger, is it fade, moisture in the fluid or fluid boiled? I checked the pads and they're fine, the rotors as well, even wear no signs of burnt or uneven layer transfer. thanks for your help in advance.

[iLuveKetchup]

My guess is the brake fluid. I'd flush to a higher temp fluid and go from there.

[empower-auto]

Motul 5.1, investigate it.

[yomny]

Thats what I was thinking, I measured the temp of the rotors after some laps and the temp gun read HI, meaning more than 680 degrees Fahrenheit. I read around Google that moisture or excessive heat could cause this.brake sensation.

[CSG David]

Flush brake fluid thoroughly. Motul RBF600 is good enough for this car. We haven't had any brake fade or fluid boiling even on high speed tracks with the BRZ on XP10/8 pads and RBF600 fluid.

[celica73]

Hard pedal means the pads are overheated and there is no friction anymore - add brake cooling and/or higher heat range pads.

Long/soft pedal means you boiled the fluid and now have some bubbles in the lines - bleed brakes with better fluid and add some brake cooling.

[yomny]

Thanks for the replies I'll definitely be changing the fluid asap and checking talk the components thoroughly. I checked the fluid reservoir and it has debris on the top filter lining, I think the car is too new to have stuff like that in there some something definitely went on.

[HP Autowerks]

Originally Posted by yomny

After a few (4-6) hot laps at my local track the cars was experiencing brake fade. What i think brake fade is, so everyone could be on the same page(correct me please if im wrong) is the build up of the binding gases of the pad between the rotor and pad, preventing braking force/bite or solid pedal feel. The event was a couple of days ago and my pedal still feels spongy and the braking force isnt adequate, at least i think it should be a lot stronger, is it fade, moisture in the fluid or fluid boiled? I checked the pads and they're fine, the rotors as well, even wear no signs of burnt or uneven layer transfer. thanks for your help in advance.

Looks like you have boiled your fluid. Flush it out and fill with high quality fluid and you are good to go!

[yomny]

Replaced the fluid along with my pads and rotors and the brakes feel amazing, firm and strong bite. The old pads where somewhat messed up, they looked like a pirahna had bit into the corners. Seems like the heat destroyed not only the fluid but the pads were harmed in such a way that the rotors were going to start seeing some uneven wear over time. Sound advice for anyone taking the car to the track, replace pads with more sports driving oriented ones and change the fluid. If the latter isn't in your plans then run maybe three laps at most.

[ill86]

Just a friendly fyi:

This is track dependant along with other factors at play. Ambient temps, tire type, tire temps and how "brake heavy" the track is for example.

I've have done over 50 laps over two small events and I'm still on oem parts and fluid. Very little initial fade and pedal feel is fine.

I don't expect them to last forever though..

Good job diagnosing your problem! Enjoy your track time.

[Dave-ROR]

Originally Posted by ill86

Just a friendly fyi:

This is track dependant along with other factors at play. Ambient temps, tire type, tire temps and how "brake heavy" the track is for example.

I've have done over 50 laps over two small events and I'm still on oem parts and fluid. Very little initial fade and pedal feel is fine.

I don't expect them to last forever though..

Good job diagnosing your problem! Enjoy your track time.

I got 2.5 laps out of them at mid ohio before fluid boiled.

[yomny]

lol there you go, so i guess its not a good idea to run the stock fluid at all lol.

[kllrnohj]

I did two track days (5x 25 minute sessions) in the FR-S - one on stock pads (those were gone at the end of the day, lol), and one on Carbotech XP8s. Didn't have any fluid boiling problems at all with stock fluid.

Brakes definitely need some extra cooling, but boiling your fluid seems a bit unusual - were you riding the brakes or something? This is a momentum car - you shouldn't be braking much

[ill86]

Originally Posted by Dave-ROR

I got 2.5 laps out of them at mid ohio before fluid boiled.

Originally Posted by yomny

lol there you go, so i guess its not a good idea to run the stock fluid at all lol.

2.5 laps?


What the hell were you doing? Lol

Anyway.. Mid Ohio is more brake dependent than PittRace. Or you were braking more. Or the track temps were different. Or the ambient temps were different. See my point?

I have over 15,000 laps here. I know my way around the track. Therefore I may not be on them as hard when I'm driving the 86 with oem brakes. I know the limits. I did not brake at 50 meters running 10/10ths.

It really depends on too many factors. A "track day" is too vague - as drivers are all very different as much as tracks and misc factors.

Do i recommend that they be upgraded? Yes.
Is it necessary? Depends on your objective.

(I am only including my experience to qualify my statements. I am a professional. Not simply a club day or volunteer instructor - sharing my experience. I am however just another guy online, so take it with a grain of salt..)