[TrackClub]

Originally Posted by GunMetalGrey

My fluid was may be one or two months old and it was either motul 660 or 600, I can’t remember which.

Once my fluid boiled I should’ve realized it would happen much easier the next time I was on the track, Even after a 60 minute break between sessions it happened again.

Does anyone know where to get Castrol SRF?

Willwood EXP

[NickyRacerBoy]

I run stock SS1LE ducting DTC70 front DTC60 rear Racing Brakes stainless steel pistons with Castrol brake fluid with ZERO fad. Not to tune my own horn but if I am not having issues you should be fine. Change to another caliper brand and your more likely to run in issues.

[LESS1]

Originally Posted by GunMetalGrey

So Willwood EXP is definitely an upgrade from the two high temp Motul brake fluids?

Yeah these Hawk DCT 70 pads are very high toque, the semi-pro driver who drove my car said it brakes like a race car with "demon brakes". One of the areas I seem to be able to catch up on other cars is deeper later braking, I don't really want to lose much if any of that, Hawk claims those pads have .8mu friction up to 1400F while the Ferodo 1.11 are close to but under .5mu, I wouldn't mind something in between perhaps

Carbotech claims their XP12 are.65mu

Cobalt says their XR2 friction level is something like the DCT60 and Ferodo DS1.11 however those two pads have very different friction levels according to their manufacturers at least.

Pads aren't the issue here... heat dissipation is. Especially in your case. Most of the replies are from getns in SS 1LE, not ZL1. Driven correctly you will carry more speed between corners. Which needs to be scrubbed off. Chevy did a good job with the brakes on these cars. They are sized right for OEM or similar compound pads. Get too aggressive with pad choice and the pedal hits the floor. Outside of going to a good brake fluid such as SRF and possibly stainless steel brake lines. I'd certainly not run an aggressive aftermarket pad on a ZL1/ZLE unless I went to a larger rotor such as AP/Essex. A side benefit of AP/Essex is thicker pads which are a heat sink that aids with cooling. For those of us that aren't very aggressive on the brakes (not me) your mileage may vary with the above comments.

Also, don't get too wrapped up in late braking. May seem faster but if you are not trail braking and releasing near the apex. You might be over braking and losing significant time doing so. For instance, if you find you are back on the throttle before the apex, chances are you just over slowed, and lost time.

[LESS1]

Originally Posted by NickyRacerBoy

I run stock SS1LE ducting DTC70 front DTC60 rear Racing Brakes stainless steel pistons with Castrol brake fluid with ZERO fad. Not to tune my own horn but if I am not having issues you should be fine. Change to another caliper brand and your more likely to run in issues.

Hello, Nicky. Remind me again your car is how many pounds from a stock porker? Less weight = less mass to slow which makes a difference here.

[Pcormier66]

Originally Posted by LESS1

Pads aren't the issue here... heat dissipation is. Especially in your case. Most of the replies are from getns in SS 1LE, not ZL1. Driven correctly you will carry more speed between corners. Which needs to be scrubbed off. Chevy did a good job with the brakes on these cars. They are sized right for OEM or similar compound pads. Get too aggressive with pad choice and the pedal hits the floor. Outside of going to a good brake fluid such as SRF and possibly stainless steel brake lines. I'd certainly not run an aggressive aftermarket pad on a ZL1/ZLE unless I went to a larger rotor such as AP/Essex. A side benefit of AP/Essex is thicker pads which are a heat sink that aids with cooling. For those of us that aren't very aggressive on the brakes (not me) your mileage may vary with the above comments.

Also, don't get too wrapped up in late braking. May seem faster but if you are not trail braking and releasing near the apex. You might be over braking and losing significant time doing so. For instance, if you find you are back on the throttle before the apex, chances are you just over slowed, and lost time.

I don't think pad choice is the issue. It's braking aggressiveness. Race pads won't generate more heat than OEM all things being equal. If the braking zone of a ZL1 with race pads is the same as a ZL1 on OEM, it will generate the same amount of heat. Race pads allow you be more aggressive - repeatedly. That's what creates the incremental heat. I can guarantee those experiencing fade on race pads are outbreaking all the ZL1's on OEM pads. But I agree that if you are not hard on brakes, OEM is perfectly adequate. If you want OEM performance with race pads, use less brake.

[Pcormier66]

Originally Posted by LESS1

Hello, Nicky. Remind me again your car is how many pounds from a stock porker? Less weight = less mass to slow which makes a difference here.

Mass is huge in braking. I had a BMW 1M for a few years. It had the exact same brakes as the M3. The advanced M3 drivers all experienced brake fade with heavy use. I could pound the 1M mercilessly without a hint of fade. 300 lbs is material.

[TrackClub]

Originally Posted by Pcormier66

I don't think pad choice is the issue. It's braking aggressiveness. Race pads won't generate more heat than OEM all things being equal. If the braking zone of a ZL1 with race pads is the same as a ZL1 on OEM, it will generate the same amount of heat. Race pads allow you be more aggressive - repeatedly. That's what creates the incremental heat. I can guarantee those experiencing fade on race pads are outbreaking all the ZL1's on OEM pads. But I agree that if you are not hard on brakes, OEM is perfectly adequate. If you want OEM performance with race pads, use less brake.

Completely disagree. Put high torque pads on and see what happens. Been there done it first hand. Nothing to do with "braking aggressivness". Too many threads here with folks with high torque pads having to mod their postons, having to go with extra cooling, shims and their calipers turning brown from heat. I have run high torque pads and had to rebuild calipers, deal with stuck pistons etc. Btw my double thickness pads didnt last al that long either. Moreover, outbraking other cars has little to do with pads and mostly with driver skill to trail brake deeper into a corner. Cheers!

[Zl1+911]

I have tracked my (now sold) ZL1 and now ZLE for 20+ track days on these two. Outside of Nicky I have the best lap times (just to show that I am not going that slow), never ONCE have I experienced brake fad. DTC 70s and Motul 600.

Two things to consider - over breaking (as one gets better u need less time on breaks), overly intrusive traction control using breaks to control the car as possibly causes.

[Pcormier66]

Originally Posted by TrackClub

Completely disagree. Put high torque pads on and see what happens. Been there done it first hand. Nothing to do with "braking aggressivness". Too many threads here with folks with high torque pads having to mod their postons, having to go with extra cooling, shims and their calipers turning brown from heat. I have run high torque pads and had to rebuild calipers, deal with stuck pistons etc. Btw my double thickness pads didnt last al that long either. Moreover, outbraking other cars has little to do with pads and mostly with driver skill to trail brake deeper into a corner. Cheers!

Is there some chemical reaction going on to create more heat with race pads?
If the clamping force between the rotor and pad is the same, the heat generation is the same. Race pads will activate ABS sooner, and more consistently, lap after lap. That's why lake braking is so much more effective, and fun, on race pads. And that's what causes higher temps, which leads to more heat soak. Said another way, you need less pedal pressure with race pads to generate the same braking performance as OEM.

I use high torque pads on all my track cars. Have for 15 years. Probably tried very brand under the sun. No fancy aftermarket cooling or parts. Just good, fresh fluid.

As for catching cars in the corners, just because you late brake doesn't mean you are not also able to trail brake. Good technique involves both. It's not one or the other. I would agree that your consistency to trail brake after a late braking event is lower. But if you get it right, the rewards are huge. And isn't that why we are doing this?

[Pcormier66]

Originally Posted by Zl1+911

I have tracked my (now sold) ZL1 and now ZLE for 20+ track days on these two. Outside of Nicky I have the best lap times (just to show that I am not going that slow), never ONCE have I experienced brake fad. DTC 70s and Motul 600.

Two things to consider - over breaking (as one gets better u need less time on breaks), overly intrusive traction control using breaks to control the car as possibly causes.

100% agree that, generally speaking, a more competent driver uses less brakes. And 100% agree that stability and traction control contribute to heat soak if you are activating the systems. I personally like to turn all the nannies off. Nothing wrong with leaving them on. The ZL1 is an expensive car. I'm new to the ZL1 platform, and to be candid, I am working my way down the ladder from full nannies to full off. I'm taking my time learning the car. After two track events on my first set of DTC70f / DTC60r, the rears are worn more than the front. I attribute that to the nannies silently correcting my attitude.

[Zl1+911]

Yeah - I get 2x rear to front life, so something is not quite right with that

[LESS1]

Originally Posted by Pcormier66

Is there some chemical reaction going on to create more heat with race pads?
If the clamping force between the rotor and pad is the same, the heat generation is the same.

Clamping force is not the only element at work here. Pad compound friction coefficient (mu) as well as rotor composition all factor in. Your “clamping” remark is not entirely correct with regards to heat, braking performance…etc. It does play a part but there are other factors at work here. Items for consideration besides pad friction coefficient include pad heat range, cold torque, hot torque, and wear rate. Rotor material composition plays a part as well. Simple physics here and no free lunches... the higher the pad friction coefficient (assuming correct rotor material) the more heat you create.

[TrackClub]

Originally Posted by LESS1

Clamping force is not the only element at work here. Pad compound friction coefficient (mu) as well as rotor composition all factor in. Your “clamping” remark is not entirely correct with regards to heat, braking performance…etc. It does play a part but there are other factors at work here. Items for consideration besides pad friction coefficient include pad heat range, cold torque, hot torque, and wear rate. Rotor material composition plays a part as well. Simple physics here and no free lunches... the higher the pad friction coefficient (assuming correct rotor material) the more heat you create.

+1. The fact that one driver experiences no issues while another does may also very well come down to a venue type(s) they run and cooling between corners.

[Pcormier66]

You're absolutely correct - it's physics. And yes there are a multitude of variables that contribute. Weight of car, HP, tire composition, track configuration, changing track conditions during a run, driver skill, caliper design, backing plate stiffness, length of the run session, proper bedding of pads to rotors, fluid condition... + 1,000 more variables

This discussion is about how changing the coefficient of friction (pad choice) affects heat creation - all other things being equal. If you want to debate every possible variable, then this is an infinite discussion. My explanation is based on a ZL1 and how pad composition influences heat creation. We are only changing the pads. We need to simplify this experiment

Clamping forces and the coefficient of friction are on one side of the equation, and brake torque is on the other side. If you increase either variable, you are changing the amount of torque the system can generate.

The clamping forces are used to generate friction that produces torque to stop the vehicle. This is where “coefficient of friction” comes into play. The coefficient of friction is calculated by dividing the force required to slide an object over a surface by the weight of the object. For example, if it takes 1 lbs of force to slide a 1-lb brake pad over a rotor, the coefficient of friction between the two materials is 1.0.

Clamping forces and the coefficient of friction are on one side of the equation, and brake torque is on the other side. If you increase either variable, you are changing the amount of torque the system can generate.https://www.knowyourparts.com/technical-resources/brakes-and-brake-components/from-pedal-to-pads-brake-systems-explained/

All things being equal, a higher torque pad will require less clamping force to generate the same coefficient of friction. There is a direct relationship between coefficient of friction and heat creation.