Payne

Guys,

I did my first HPDE at Thunderhill yesterday and was having a damn good time, but ran into some brake fade, bad enough that I ended up going off course on my last lap when I got nothing out of the brakes...

My setup-

C6 z06 brake ducts with 2.5" hose directly to the rotor (touching the rotor, aimed into the fins)
SS lines
XP-10s up front XP-8s out back
Motul 600 with a full flush
Stock Calipers

Car-
Pfadt coilovers
T1 bars
710s
489rwhp 383
3.90s

So the question is where is the problem - the pads or the fluid? I'm still on stock pistons, so I hear that going to vented SS pistons makes a huge difference, so I guess that will be my next step unless anyone can make a suggestion different...

96CollectorSport

Did your pedal go to the floor or did the car just not slow down?

Brake fade happens 2 ways,
1) Fluid, air has entered the system through, boiling the fluid, air in the system from a leak, or just some air that didn't get blead out the last time the car was serviced. When you have air in the system that is when the pedal goes down, either all the way to the floor or enough to get your attention.

2) Pads, if the pads get overheated they will not work as they had before and the rotors will either be coated or spotted. When that happens the pedal will not go down all the way but the car will just not slow down like it had before. If that happens it's time to step up the heat range in pads.

AU N EGL

489 rwhp and Carbotch XP-10S and 8s ?

Carbothecs are very good brake pads, however, I think you may have OVER motored your brake pads.
Lots of HP and ( you did not mention your braking style) late braking can melt brake pads and cause brake fade the next time out.

With that much HP I would think you need race pads, XP12s-XP11s, Wilwood H, PFC-01s or 05s, Hawk DTC-60s or DTC70s.

J Ritt

As mentioned, you need to define whether or not the pedal went soft (fluid fade), or your pads faded (firm pedal, but car wasn't slowing down). It sounds like it may have been fluid fade.

Your car is obviously very fast with the power you're laying down. I'm assuming you're also running sticky tires?

Regardless of the type of fade, I would try Hawk DTC-70 front and rear pads as a first step. They will be more heat resistant. You can get them from LG motorsports. We have them on the shelf and ready to ship.

After that, you could try the SS pistons as the economical route. Honestly though, I don't think that's going to cut it for you given the power level and the speeds you're likely hitting. The primary issue here is heat capacity. You could try a stock-sized rotor that flows more air (our AeroRotor DRK for example), but stock-sized rotors may not have enough mass to handle the thermal stress you're putting on them(especially since they aren't working with the added air from the ducts). For that, you'll need a rotor with greater mass...a bigger heat sink.

Since you're running ducts, pads, and fluids, there aren't that many options left. I'd take a serious look at a front brake system. We sell a four piston front upgrade with a 14" rotor that would be appropriate. You can see more details here: http://www.stoptech.com/products/BBK/summary.shtml
It will allow you to run all day, every day without any fade or issues. When you're done with them and sell the car, you can usually get $0.50 on the dollar for them, and they are rebuildable, etc.

Let me know if you have any other questions. Thanks,
Jeff
StopTech
jeff@stoptech.com

Last C5

EeeeeeeK! I don't like the sound of this. That's the same set up I'm putting together right now (with less horsepower) Come on guys lets' here the fix.

Sidney004

One last question; did you inspect the brake pad linings yet? Was there any pad material left? Those symptoms sound like you burnt thru your pads especially if this only occurred on your last session.

wallyman424

when my pads dip below 60% material I get a much longer, softer pedal. I think its pretty much normal, and just happens by the design of the caliper.

Lancer033

how long was the fluid in the car?

John Shiels

could also be from taper. You can get heat shields and shim the pads also especially if they are thick ones like the Wilwood SL-6 .80"

danswofford

I run almost the same setup on my C5 Z06.

Motul
SS
cooling
stock rotors and calipers.

However, I run Carboteck 12/10s and have stainless steel pistons.

I run Thunderhill and I drive deep and brake hard there and the car stops hard every time all day. I'll bet you faded into turn 10, downhill, its hard on brakes. It is a brake zone of about 110 MPH to 60, I faded there and went off course when I fried Hawk + pads.

I'd suggest changing to 12/10s bleeding your brakes and going at it again.

danswofford

[QUOTE=Payne;1558078676]Guys,

I did my first HPDE at Thunderhill QUOTE]

You going to Laguna Seca Jan 2?

0Randy@DRM

Maybe not enough cooling??? We played with 2 inch outlets and it didn't work.

Randy
PS I know nothing about those pads you are running, it could be that too.

Timz06

I run the stock brakes with carbotech xp 10's and never had a problem. Use cheap valvoline synthetic fluid, and I have driven the hell out of the car

0C5stein

2.5" hose Probably too small for adequate air volume to cool a stock rotor

XP-10s up front XP-8s out back I can hook you up with some XP 12 & XP10s and that would work alot better if you are putting too much heat in your system

710s What size? I've seen some significant brake issues caused by running the wrong diameter tire combination which is engaging the ABS prematurely

I think that you need a new set of Big brakes from Stoptech, Baer or Performance Friction from Santa Claus. Did I mention that we Deliver For 'ol Saint Nick?

John Shiels

did the pads chunk?

96LT1

Come on people... don't try to sell him something until you find out what the problem is.

I've beat XP10s and the OEM rotors and calipers without having them fade.

I've also had fade from regardless of what BRAND of pad I've used because I tried to get every little bit out of them. Thin pads on stock caliper/pistons equate to no heat isolation.

96GS#007

Sounds like a technique issue to me versus an equipment issue.

bsim

AU N EGL

Braking too late is a possibilty. try braking a bit earlier.

Instead of braking at the 2 marker try the 2 1/2. Some brake pads just work better if you use them a bit sooner, not all brake pads can go to the last moment to stop your car.

Sidney004

There are a lot of conclusions, speculation and opinions as to the cause and cure PRIOR to a through inspection of the braking system. A lot of the input given here may be on target but....
Observing the fluid flow by bleeding the brakes in the condition they are now will tell you if the fluid boiled(i.e. bubbles and coloration, motul turns brown.)
The physical condition of the pads will determine if the fade came from 1)metal to metal contact between backing plate and rotor 2) high heat transfer to fluid from minimal pad material 3) pad chunking due to delamination or wrong heat range.
Other problems could occur from the rotor being severely cracked(thumping noise should of occured.) Fluid seepage from the pistons could indicate a seal tear. The condition of the retaining pin, etc.
Payne, the solution to your problem may have already been touched on by the other people posting valuable comments and insight, but as someone who has experienced brake fade multiple times at Thunderhill, I would take the steps above first to determine your baseline before changing your driving style or upgrading your braking system(although thats not a bad idea, who wouldn't want a set of Stoptech's, Brembo's or the like on our Corvette.) I live in Castro Valley, so if you are close by, I would be happy to help you inspect your brake system.