Can track cars typically threshold brake every lap?

[Lance Dolan]

I'm an HPDE student who has experienced brake fade. I was (attempting) threshold braking at every opportunity around the track. I want to be able to drive that way and not get brake fade.

However, I have no idea if that's a reasonable expectation.

My brake fade experience happened in my c6 grand sport, bone stock. However, driving similarly in my much lighter lotus Elise, also stock, I never had brake fade. So this anecdotal experience makes me believe that your typical lightweight car, especially those in track prep, can be (and often is) driven with max braking and not much risk of overheating/boiling/fading.

Are typical nasa racers threshold braking in every single braking zone where it's the fastest way around the track? Or are even the gnarliest drivers trying to strike a balance of when to cool brakes vs use brakes hard in order to avoid fade?

What percentage of cars do you think in a typical HPDE 3/4 session are capable of doing maximum braking throughout their entire session without much brake fade risk? Are 80% of them threshold braking consistently without issue, or are 80% of them picking and choosing when to max out the brakes because brake fade is a real concern for them?

I have no sense for how often drivers are braking hard as possible.

Also, I'm now ditching the street cars and shopping for a car already in track prep that can be driven hard w/o overheating. I'm already familiar with power and drivetrain cooling, but what really makes a brake system capable of withstanding threshold braking?? Lightweight car, big disks for higher thermal capacity, mods to pass more air over the brakes..? Anything else? I'm not sure how to buy a car that does what I want: brakes hard all day and doesn't fade. No idea how to tell whether I'm looking at a track car that will brake fade.

Thanks guys, it's been a really awesome community so far. Pretty pumped to get more into it.

Edited July 16, 2022 by Lance Dolan

[JimM]

When you had brake fade in the C6, what pads (make and pad compound) were you running?  Many people will swap to higher temp compound brake pads for the track (or swap in the track pads plus dedicated rotors), so if you were running a compound designed to just work on the street, then that could cause issues.  Also, what brake fluid are you running in the C6, and when was the last time you replaced or at least flushed it?    I've heard that brake fluid is hygroscopic – it absorbs moisture that permeates through the rubber hoses, seals, and via various fittings, and that absorbed moisture will lower the boiling point.  I think that brake fluid replacement is suggested fairly often (every few years), and bleeding it is also a good idea.  Personally, I used Motul RBF600 brake fluid in the cars I tracked (2001 Audi S4 and a 2000 Honda Civic hatch race car). 

If you do decide to add brake ducts, it may be tough to get the air to flow exactly where you want especially in a FWD and AWD car as you have to worry about the ducts hitting the axles, but I think you need to have the air exiting where the center of the hub is instead of against the face of the rotor.  - Jim