this past weekend at the track I got meatballed for sparks flying off my brake discs/pads. My current setup is the PST track day pads /w stock replacement rotors, lines, calipers on a stock c6 corvette. I am able to find the ABS every time the amount of pedal pressure required is inconsistent so I end up pressing until I feel ABS pulse back off a bit and then depress again...
My current pads and rotors will last another 5-6 sessions so 1 or 2 days (since most of my events are 1/2 day events) and then i'll replace everything... I got about 3 sets of pads worth of time out of the rotors
I am facing a few options and looking for some input.
#1: buy the same rotors again, get a higher temp pad (thinking Hawk DTC 60) throw some braided lines in (existing lines are original to the car so 16 years old) and run it. Least expensive option
#2: go up to Z51 front discs, they are roughly 1" larger, get some fancy DBA T3 rotors and do the rest, the extra thermal capacity of the rotor should help and the better heat handling of the DBA rotors also help allow me to run a slightly less aggressive pad. Cost is about $500 more to go this route
#3: go max effort on the factory calipers, get some GiroDiscs and everything else, cost for this is around $850 over the base replacement. I could always add some Wilwood calipers to this setup down the line for another $1000 since the GiroDisc rotors are the same size as the Wilwood spec37 but I think the GiroDisc rings are alot more money.
#4: give up on sport class and throw a big brake kit on the front, go with the Wilwood spec Corvette setup and some matched rear pads, cost for this is around $2000 more than the base but it also puts me into the tuner class in SCCA time trials and that opens up the possibility to spend ALOT more money (headers, tune, coilovers, etc.)
#5: file for divorce, get the credit card as hot as the brake rotors were and just build the thing for tuner class
ClearWaterMS said:
#5: file for divorce, get the credit card as hot as the brake rotors were and just build the thing for tuner class
Well, that certainly is a choice, but I'm pretty certain that's not the correct choice.
Let me ask around the office to see if anyone has advice.
So is the issue you're trying to solve that brake temps are getting too high? That and pedal feel inconsistency?
I'd start with some temp stickers on the calipers to see what you're really dealing with.
What sort of ducting are you running?
Sparks flying off rotors/pads is not unusual at all. Our S197 Mustang project was a total fireworks show from the front brakes, even at autocross speeds. And it sounds like the brakes are working fine and not having any heat-related failure symptoms in the current configuration.
Honestly my first approach would be a chat with whoever asked for the meatball flag to see why they thought a totally normal thing for performance pads to do was worth an equipment warning, followed by some temp stickers to see how hot things are actually getting.
Replace your master cylinder. I was having inconsistent braking and that fixed it for me on my c5. Seals are just getting old and you're probably having some leakage. Might try a tech 2 ABS bleed first though.
Maybe try a air deflector kit
https://vorshlag-store.com/products/vorshlag-c6-corvette-brake-cooling-deflector-kit
You might look at the Cadilac ATS brakes. I know people use them on the C5. That means 99% it'll work on a c6.
Tom Suddard said:
So is the issue you're trying to solve that brake temps are getting too high? That and pedal feel inconsistency?
I'd start with some temp stickers on the calipers to see what you're really dealing with.
What sort of ducting are you running?
i have the factory plastic ducts that pull air in from the outside and push it vaguely into the area of the tire (I didn't design it i just installed it) I have not ducted that air to the back of the hub yet.
as somebody who is new to the hobby, my goals are a bit more ambiguous. I don't know if pads, rotors, etc. will fix pedal feel... my ultimate goal is to spend the least amount possible while ensuring I have reliable repeatable brakes that can stand up to the abuse of somebody who is getting comfortable braking deeper and deeper and is starting to learn threshold braking...
I'd flush all the fluid with new fluid (high temp fluid) and get some good braided brake lines and call it good.
The temperature paint or temperature stickers on the rotor and caliper will tell you if you are in the right window.
theruleslawyer said:
Replace your master cylinder. I was having inconsistent braking and that fixed it for me on my c5. Seals are just getting old and you're probably having some leakage. Might try a tech 2 ABS bleed first though.
Maybe try a air deflector kit
https://vorshlag-store.com/products/vorshlag-c6-corvette-brake-cooling-deflector-kit
You might look at the Cadilac ATS brakes. I know people use them on the C5. That means 99% it'll work on a c6.
i have read about the ATS brakes but i think once I put a different caliper on that isn't offered on that car it's better to just go aftermarket as the car still ends up in tuner class. Additionally, the benefit of an aftermarket caliper is a MUCH larger pad that will last alot longer and 2 piece rotors. The spec setup from KNS for the corvette is $2600 and even includes a set of BP-40 race pads. AP's setup is a bit more at $3100 but doesn't include pads.
However those brake cooling deflectors look like just the ticket, inexpensive, easy to install, won't be invalid as other upgrades may be needed in time...
wvumtnbkr said:
I'd flush all the fluid with new fluid (high temp fluid) and get some good braided brake lines and call it good.
The temperature paint or temperature stickers on the rotor and caliper will tell you if you are in the right window.
i have run RBF600 for 3 years and flushed it this spring with a Motiv bleeder. After the "spraking brakes" i bled the system over the weekend...
I run Centric rotors on everything. I haven't noticed that expensive rotors make much difference unless they are bigger.
Pads depend on what I'm doing. I have run the Power Stop track day pads. They worked well but didn't like the heat. They need some decent cooling to keep them from transferring material to the rotors. I've had better luck with EBC's Orange Stuff and Porterfields E4 pads.
ClearWaterMS said: my ultimate goal is to spend the least amount possible while ensuring I have reliable repeatable brakes that can stand up to the abuse of somebody who is getting comfortable braking deeper and deeper and is starting to learn threshold braking...
If this is really your goal, I think you're in the wrong car. You could easily purchase a track Miata with the money you'd save on consumables by driving the Miata instead of the C6. Once you're close to Spec Miata lap times and want to add a zero to your annual spending and your top speeds you can go back to the C6.
CrashDummy said:
ClearWaterMS said: my ultimate goal is to spend the least amount possible while ensuring I have reliable repeatable brakes that can stand up to the abuse of somebody who is getting comfortable braking deeper and deeper and is starting to learn threshold braking...
If this is really your goal, I think you're in the wrong car. You could easily purchase a track Miata with the money you'd save on consumables by driving the Miata instead of the C6. Once you're close to Spec Miata lap times and want to add a zero to your annual spending and your top speeds you can go back to the C6.
trust me this thought has gone through my brain multiple times; i love the miata platform i simply don't fit in them without significantly sacrifice (i'm 6'2 and 240 pounds with a longer than average torso)
To everybody else, I think i'm going to run with what I have, i'm going to upgrade the lines add the vorshlag cooling plates and when these pads and rotors bite it i'll grab some higher temp pads and replacement rotor blanks, i'll skip the 2 piece rotors and BBK for now
ClearWaterMS said:
as somebody who is new to the hobby, my goals are a bit more ambiguous. I don't know if pads, rotors, etc. will fix pedal feel... my ultimate goal is to spend the least amount possible while ensuring I have reliable repeatable brakes that can stand up to the abuse of somebody who is getting comfortable braking deeper and deeper and is starting to learn threshold braking...
Pads and rotors aren't going to do a ton for pedal feel. At least if they are in reasonable condition. SS brake lines. New master cylinder. ABS bleed. New calipers might help with flex. FWIW a lot of the spec corvette racers are actually removing the ducting to spindles. Apparently its not super needed, at least for a c5.
Still I'd bet on air in the ABS pump or MC as the inconsistent brake height. Have you looked into pad knockback causes for the c6? You can get anti-knockback springs. It would cause different pedal height engagement.
If the pedal feel is inconsistent, as in the ABS engagement point moves back and forth rather than consistently gets lower/squishier with temperature, that's a hydraulic system problem or possibly a wheel bearing problem. Sparking is normal for some pads, some will just make sparks until they're broken in.
I've run PSTs in the past, they're barely trackable street pads IMO, I'd recommend at least moving up to PSAs - note that there seems to be supply issues with them though. EBC Bluestuff NDX or EBC Yellowstuff could be good options too.
So since you haven't run into any clear temperature issues yet (in my experience with the PSTs, that would involve scraping noises and smoldering pads that disappear rapidly) I'd recommend that you stick with the same size rotors, check your wheel bearings and MC, skip the braided lines (they're a packaging nightmare and make a vanishingly minor difference to brake feel vs. rubber lines that are in good condition) and see how that works.
GameboyRMH said:
If the pedal feel is inconsistent, as in the ABS engagement point moves back and forth rather than consistently gets lower/squishier with temperature, that's a hydraulic system problem or possibly a wheel bearing problem. Sparking is normal for some pads, some will just make sparks until they're broken in.
I've run PSTs in the past, they're barely trackable street pads IMO, I'd recommend at least moving up to PSAs - note that there seems to be supply issues with them though. EBC Bluestuff NDX or EBC Yellowstuff could be good options too.
So since you haven't run into any clear temperature issues yet (in my experience with the PSTs, that would involve scraping noises and smoldering pads that disappear rapidly) I'd recommend that you stick with the same size rotors, check your wheel bearings and MC, skip the braided lines (they're a packaging nightmare and make a vanishingly minor difference to brake feel vs. rubber lines that are in good condition) and see how that works.
when I say ABS engagement is inconsistent, is that the pedal travels the same amount to get into ABS all the time but the amount of braking performance i get changes... aka the brake pads are probably overheating...
I got meatballed on the 3rd session of the evening for glowing rotors and sparks flying off the rotors, in the second session I ended early because the brakes were feeling a bit wooden and performance was falling off, that is what I mean by ABS being inconsistent... i know that pad taper is a real problem on the c6 and that can increase pedal travel, i believe its caused by the sliding caliper design having equal sized pistons on both sides of the caliper. I also know that swapping the pads left side to right side restores performance and I typically do that @ roughly halfway through the usable life of the pads.
JG Pasterjak said:
Sparks flying off rotors/pads is not unusual at all. Our S197 Mustang project was a total fireworks show from the front brakes, even at autocross speeds. And it sounds like the brakes are working fine and not having any heat-related failure symptoms in the current configuration.
Honestly my first approach would be a chat with whoever asked for the meatball flag to see why they thought a totally normal thing for performance pads to do was worth an equipment warning, followed by some temp stickers to see how hot things are actually getting.
it was probably a corner worker, i spoke to race control after the session and he admitted he did it as an abundance of caution and given it was at the end of an evening event which meant it was dusk the sparks / glowing rotors were more visible...
Visible sparks will almost always get a call into race control at least as a caution from the CW. I know I would call it when I flagged. Usually the car is going too fast to know if it's brakes, a dragging part, or something different. If it was showering enough repeatedly, I totally get the call.
For rotors, Centric high carbon for me every time. They just work for me in all applications. Then I agree with the temp paint
Get real track pads (DTC60 is a fine next choice)
Centric premium rotors (120 series)
Fresh hi-temp brake fluid. I'm a fan of Castrol SRF because of the unmatched wet boiling point, allowing for longer flush intervals, but there are cheaper options with similar dry performance.
thank you to everybody on the thread, I did everything that was recommended.
I picked up the brake scoops from Vorschlag, got a scan tool that can do ABS brake bleeds, swapped the pads over to DTC-60 and installed new Centric blanks. I took it around the block for a quick 10 min drive and hope to bed the brakes later this week. The brake pedal feel is back to normal.
I used Powerstop rotors and pads on the wife's CX5 and I'm impressed enough that I'll be using them going forward. A note on the Z51 brakes: GM only makes the left front rotor (may be the right) so the other side has the vanes turning the wrong direction. Powerstop has a replacement for both sides so the brakes get proper cooling.
Good advice. Definitely get the high temp rotor paint and temp stickers to start building a base line with the new set up.
Good Luck
triumph7 said:
I used Powerstop rotors and pads on the wife's CX5 and I'm impressed enough that I'll be using them going forward. A note on the Z51 brakes: GM only makes the left front rotor (may be the right) so the other side has the vanes turning the wrong direction. Powerstop has a replacement for both sides so the brakes get proper cooling.
centric makes blanks that are the correct size. I had to do some centric part number reverse engineering but they were available from Summit and Amazon for around $100 a piece. I didn't end up /w the Centric blanks because of the torque multiplication of moving the caliper further from the hub center potentially changing everything and the idea that with improved cooling i might not need them.
Centric 125.62086
https://www.amazon.com/Centric-125-62086-Brake-Rotor/dp/B004HEFCVM
