ND brake fade on track
 

Hey team! I’m looking for some advice on some brake fade I’m getting after about my first or second 20 minute session on track. I have G-loc R10 front and R8 rear with ATE type 200 fluid and stock (non-brembo) everything else brake wise.

I don’t think I’m boiling fluid, but my pedal travel and effort slowly increase throughout the day and by the end it gets a tad sketchy. Do you guys think stainless lines and some higher temp fluid will get help me maintain a firm pedal all day? Cooling ducts? Use less brakes and send it?

I should add that I’m running 200TW tires as well*

How well are you bleeding? I didn't have problems with my ND brakes on track with 205/45/17 200TW tires, but I imagine that would change with wider tires. I did have the Brembo front calipers and ran Motul 660 fluid, though. I have a Verus ducting kit that was never used for sale if that interests you.

full on bleed with speed bleeders, 4 jack stands, probably twice as much fluid as needed. Brakes are flawless until they start to get really hot.

I’d guess your Brembos shed heat faster than my steel calipers, so that might be a large part of it.

Are you getting brake fade, or is the feel of the brakes changing as you wear the pads? From your description, it sounds like the latter -- which makes me think you are getting pad taper.

??

Brakes change during a session and come back a good bit after the ~40 minute break between sessions. It doesn’t fully come back until after the 90 minute lunch though. It’s for sure related to thermal load in some way. Is it rubber lines heating up and expanding? Pads trying to operate outside of their temp range? That I don’t know. I do know my pedal is almost at the floor by the end of the session.

I’m going to throw some Castrol SRF in and braided lines and see what happens. Just wanted to see if anyone else has experienced the same as me and knew the fix, so I don’t toss money at the wrong problem.

Get some of those thermal strips and apply them to the callipers. For science, and knowing if higher temp fluid is needed.

From over here it sounds like fluid, but getting a temperature read should settle that one way or the other.

That’s actually a really good idea! I’m not sure when my track day is, but I’ll be sure to update the thread with temperature data afterwards.

What track? What’s your time vs local spec Miata times?

The Ridge in Shelton, WA.

Times are right at spec Miata times of just under 2 minutes.

Oh, what's up local. I've got a few hours under my belt at that track. Glad you're getting some decent times there. The brake lines are meant to withstand ~1500psi, if they started expanding with heat, you'd have real problems. They're not a bad item to replace for peace of mind, but I don't think that's where your fade is coming from. If you followed G-loc's bedding procedure, you might look into a more aggressive pad.

Maybe I’ll see you out there some time! Black #38 ND2 soft top.

I just ordered up some Castrol SRF and temp strips for my calipers. We shall see what happens, but I’m open to higher temp range pads.

I just had this same issue a couple weekends ago at Buttonwillow with the same pads. I think you'll probably want to move to R12/10 for your next set of pads.

yeah, that’s probably what I’ll do next summer.

I’ve got temp sensors on the calipers now, but we will have to wait till spring to collect any data. I’ll update this thread when I have any updates.

I used to run R12/10 on my racecar, then on the MSM. R12 dust is nothing like R10, it is sticky and sets hard - it will ruin the finish if you don't do a good job of getting it off quickly. Please don't ask me how I know this.