Caliper spread at track - C5 Z06
04-23-2012, 09:45 PM
#1
Drifting
Thread Starter
Caliper spread at track - C5 Z06
Hey guys, I was wondering if anyone else had consistent bad caliper spread on a C5 Z06. In order for the pedal to be firm at Sebring in every corner I have to essentially double pump the brakes. It gets kind of annoying. Just before entry I quickly tap it once and on the second tap I hold it like normal. Otherwise, the pedal goes down really far before taking effect. Is there any way to fix this? Are my calipers going bad? The car only has 20,000 miles on it and 6 track days.
My setup is:
DBA 4000 F rotors / stock rear
RP2 front pads / XP10 rear
Motul 600 / Doug Rippie brake kit
I'm in the advanced group running on Nitto NT 555 RII's. I burned through the RP2's in 2 days at Sebring.
Is this just the limit of what the stock brakes can do? Think it's time to move to a BBK? I was pushing the brakes pretty hard.
Doesn't Wildwood make a front kit that fits under the oem 17's?
My setup is:
DBA 4000 F rotors / stock rear
RP2 front pads / XP10 rear
Motul 600 / Doug Rippie brake kit
I'm in the advanced group running on Nitto NT 555 RII's. I burned through the RP2's in 2 days at Sebring.
Is this just the limit of what the stock brakes can do? Think it's time to move to a BBK? I was pushing the brakes pretty hard.
Doesn't Wildwood make a front kit that fits under the oem 17's?
Last edited by JeremyGSU; 04-23-2012 at 10:16 PM.
04-23-2012, 10:23 PM
#2
Racer
I haven't ran the RP2 pad in TT or sprint races but going through a set of skinny OEM pads in 2 days is possible if the track is hard braking and you do a ton of laps. CMP comes to mind 
04-23-2012, 10:33 PM
#4
Le Mans Master
I have the stock rotors and Carbotechs on mine. As the pads wear I tend to get a bit of a longer pedal. Also depending on how bumpy the track surface is, the pistons will get bumped back into the caliper. That usually happens after a long straight. I just roll my left foot over and tap the brake pedal to set the pistons/pads and remove the excess play before braking in earnest. Also was told that as the pads wear and the pistons are out of the calipers further, the dust boots will tend to pull the pistons back and increase the play. Sounds logical to me.
04-23-2012, 11:19 PM
#5
Drifting
Thread Starter
No, we manually bleed them each time using two people. I don't want to have to do the "tap" method on every straight away. Gets annoying and I've never driven a car where I have to do that.
04-23-2012, 11:52 PM
#6
Safety Car
I don't engage in this tap stuff. If the pedal is going lower as the day goes on, I just add a shim or 2 to my custom brake pedal cover. But with SRF in system I really don't have to do this at all on the toughest of braking tracks. I'm in ABS most of the way on 2 of the 3 brake zones on the R-II's.
04-24-2012, 12:06 AM
#8
Le Mans Master
After several years of this hobby, I'm convinced that the whole "caliper spread" issue is just internet hype. I have hundreds of hard laps on the same calipers over the last 2-1/2 years. During that time I experienced highs and lows with brake performance and none of the bad times were ever related to caliper spread. I've measured brand new calipers against the ones I've beaten the snot out of and they are exactly the same. Brian (travisnd) can confirm the exact same results after measuring his after similar usage.
There was a period of time that lasted about 6 months where I couldn't get a good pedal no matter what I tried. I flushed the system like crazy and even replaced the master cylinder, but never was able to get it right so I assumed the calipers were bad and I removed them.
Well I just put the exact same calipers back on the car and the pedal hasn't felt this good since the day I bought the car. I don't know what it was or what changed, but it obvioulsy wasn't "caliper spread".
One thing for sure is that the system is extremely sensitive to pad taper so I recommend flipping pads and swapping side to side very often.
There was a period of time that lasted about 6 months where I couldn't get a good pedal no matter what I tried. I flushed the system like crazy and even replaced the master cylinder, but never was able to get it right so I assumed the calipers were bad and I removed them.
Well I just put the exact same calipers back on the car and the pedal hasn't felt this good since the day I bought the car. I don't know what it was or what changed, but it obvioulsy wasn't "caliper spread".
One thing for sure is that the system is extremely sensitive to pad taper so I recommend flipping pads and swapping side to side very often.
04-24-2012, 12:36 AM
#9
Race Director
After several years of this hobby, I'm convinced that the whole "caliper spread" issue is just internet hype. I have hundreds of hard laps on the same calipers over the last 2-1/2 years. During that time I experienced highs and lows with brake performance and none of the bad times were ever related to caliper spread. I've measured brand new calipers against the ones I've beaten the snot out of and they are exactly the same. Brian (travisnd) can confirm the exact same results after measuring his after similar usage.
There was a period of time that lasted about 6 months where I couldn't get a good pedal no matter what I tried. I flushed the system like crazy and even replaced the master cylinder, but never was able to get it right so I assumed the calipers were bad and I removed them.
Well I just put the exact same calipers back on the car and the pedal hasn't felt this good since the day I bought the car. I don't know what it was or what changed, but it obvioulsy wasn't "caliper spread".
One thing for sure is that the system is extremely sensitive to pad taper so I recommend flipping pads and swapping side to side very often.
There was a period of time that lasted about 6 months where I couldn't get a good pedal no matter what I tried. I flushed the system like crazy and even replaced the master cylinder, but never was able to get it right so I assumed the calipers were bad and I removed them.
Well I just put the exact same calipers back on the car and the pedal hasn't felt this good since the day I bought the car. I don't know what it was or what changed, but it obvioulsy wasn't "caliper spread".
One thing for sure is that the system is extremely sensitive to pad taper so I recommend flipping pads and swapping side to side very often.
A certain amount of pad taper is "normal" with sliding caliper brakes, it's just the physics of how it works. I have never seen documentation of permanently spread calipers, due to normal track use. If you have photos of measurable permanent spread, please post them to this thread. Enlighten us all. A soft and or long pedal can be caused by quite a few things.
04-24-2012, 08:29 AM
#10
Burning Brakes
After several years of this hobby, I'm convinced that the whole "caliper spread" issue is just internet hype. I have hundreds of hard laps on the same calipers over the last 2-1/2 years. During that time I experienced highs and lows with brake performance and none of the bad times were ever related to caliper spread. I've measured brand new calipers against the ones I've beaten the snot out of and they are exactly the same. Brian (travisnd) can confirm the exact same results after measuring his after similar usage.
There was a period of time that lasted about 6 months where I couldn't get a good pedal no matter what I tried. I flushed the system like crazy and even replaced the master cylinder, but never was able to get it right so I assumed the calipers were bad and I removed them.
Well I just put the exact same calipers back on the car and the pedal hasn't felt this good since the day I bought the car. I don't know what it was or what changed, but it obvioulsy wasn't "caliper spread".
One thing for sure is that the system is extremely sensitive to pad taper so I recommend flipping pads and swapping side to side very often.
There was a period of time that lasted about 6 months where I couldn't get a good pedal no matter what I tried. I flushed the system like crazy and even replaced the master cylinder, but never was able to get it right so I assumed the calipers were bad and I removed them.
Well I just put the exact same calipers back on the car and the pedal hasn't felt this good since the day I bought the car. I don't know what it was or what changed, but it obvioulsy wasn't "caliper spread".
One thing for sure is that the system is extremely sensitive to pad taper so I recommend flipping pads and swapping side to side very often.
So I put on some Wilwood SL6 front calipers thinking that would solve the problem... not much better. Then I changed my brake master, no better. I bled my brakes after every single race and just couldn't figure out what was going on with them. So I decided to switch over to Hawk DTC-70 brakes and Ferodo Racing brake fluid and my pedal instantly got better. I ran them at Nashville SS and Roebling Road (5 races total) and never once bled them or even took the calipers off to change pads. I had good brakes even with the pads not having much material left.
The conclusion that I came to was that it wasn't the Carbotech brakes... I think they were fine. I felt it was the fluid. I'm considering going to Castrol SRF next year, but I just wish it wasn't so pricey. But if it keeps a good pedal and not have to bleed after every session... I'm all for it.
Last edited by PushinTheLimit; 05-14-2012 at 08:25 AM.
04-24-2012, 08:39 AM
#11
Drifting
Thread Starter
Last year, I fought a long soft pedal for about 2/3rds of the season. It was very frustrating and cause some tense moments for me out on the track. I was using Carbotech XP12, XP10 pads and Amsoil DOT4 fluid. After about 5 laps into a race, I would always have to double pump my brakes for all turns.
So I put on some Wilwood SL6 front calipers thinking that would solve the problem... not much better. Then I changed my brake master, no better. I bled my brakes after every single race and just couldn't figure out what was going on with them. So I decided to switch over to Hawk DTC-70 brakes and Ferodo Racing brake fluid and my pedal instantly got better. I ran them at Nashville SS and Roebling Road (5 races total) and never once bled them or even took the calipers off to change pads. I had good brakes even with the pads not having much material left.
The conclusion that I came to was that it wasn't the Carbotech brakes... I think they were fine. I felt it was the fluid. I'm considering going to Castrol SRF next year, but I just wish it wasn't so pricey. But if it keeps a good pedal and not have to bleed after every session... I'm all for it.
So I put on some Wilwood SL6 front calipers thinking that would solve the problem... not much better. Then I changed my brake master, no better. I bled my brakes after every single race and just couldn't figure out what was going on with them. So I decided to switch over to Hawk DTC-70 brakes and Ferodo Racing brake fluid and my pedal instantly got better. I ran them at Nashville SS and Roebling Road (5 races total) and never once bled them or even took the calipers off to change pads. I had good brakes even with the pads not having much material left.
The conclusion that I came to was that it wasn't the Carbotech brakes... I think they were fine. I felt it was the fluid. I'm considering going to Castrol SRF next year, but I just wish it wasn't so pricey. But if it keeps a good pedal and not have to bleed after every session... I'm all for it.
I'll try running a number of different fluids and see what happens. Perhaps it is as simple as that.
04-24-2012, 08:40 AM
#12
Drifting
Thread Starter
Have you checked your brake fluid at the end of the day? If you bleed a little from the front calipers and the fluid comes out black when new fluid is clear, then that will affect pedal height.
I don't engage in this tap stuff. If the pedal is going lower as the day goes on, I just add a shim or 2 to my custom brake pedal cover. But with SRF in system I really don't have to do this at all on the toughest of braking tracks. I'm in ABS most of the way on 2 of the 3 brake zones on the R-II's.
I don't engage in this tap stuff. If the pedal is going lower as the day goes on, I just add a shim or 2 to my custom brake pedal cover. But with SRF in system I really don't have to do this at all on the toughest of braking tracks. I'm in ABS most of the way on 2 of the 3 brake zones on the R-II's.
I think I'm going to try a different fluid and see what happens before swapping calipers, pads, etc. One thing at a time. If a lot of guys are having success with the oem setup then I need to try some different combos.
04-24-2012, 10:12 AM
#13
Burning Brakes
Hey guys, I was wondering if anyone else had consistent bad caliper spread on a C5 Z06. In order for the pedal to be firm at Sebring in every corner I have to essentially double pump the brakes. It gets kind of annoying. Just before entry I quickly tap it once and on the second tap I hold it like normal. Otherwise, the pedal goes down really far before taking effect. Is there any way to fix this? Are my calipers going bad? The car only has 20,000 miles on it and 6 track days.
My setup is:
DBA 4000 F rotors / stock rear
RP2 front pads / XP10 rear
Motul 600 / Doug Rippie brake kit
I'm in the advanced group running on Nitto NT 555 RII's. I burned through the RP2's in 2 days at Sebring.
Is this just the limit of what the stock brakes can do? Think it's time to move to a BBK? I was pushing the brakes pretty hard.
Doesn't Wildwood make a front kit that fits under the oem 17's?
My setup is:
DBA 4000 F rotors / stock rear
RP2 front pads / XP10 rear
Motul 600 / Doug Rippie brake kit
I'm in the advanced group running on Nitto NT 555 RII's. I burned through the RP2's in 2 days at Sebring.
Is this just the limit of what the stock brakes can do? Think it's time to move to a BBK? I was pushing the brakes pretty hard.
Doesn't Wildwood make a front kit that fits under the oem 17's?
04-24-2012, 10:26 AM
#14
Advanced
Member Since: Oct 2011
Location: Lewisville TX
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How fresh are your wheel hub bearings? As they age, the piston knock-back can increase.
A quote from SKF:
'The SKF Corvette Racing Hub unit is designed to provide high stiffness during cornering, thereby reducing piston knock-back and the need to trail brake.'
A quote from SKF:
'The SKF Corvette Racing Hub unit is designed to provide high stiffness during cornering, thereby reducing piston knock-back and the need to trail brake.'
04-24-2012, 10:57 AM
#15
Racer
there are lots of items at play, but for sure the SKF seem to do much better in this regard, even with slide rail calipers
04-24-2012, 12:32 PM
#16
Safety Car
Yeah, it was somewhat dirty but not terribly. My student was running Motul 600 that was fresh in the beginning and was dirty towards the middle of the day too.
I think I'm going to try a different fluid and see what happens before swapping calipers, pads, etc. One thing at a time. If a lot of guys are having success with the oem setup then I need to try some different combos.
I think I'm going to try a different fluid and see what happens before swapping calipers, pads, etc. One thing at a time. If a lot of guys are having success with the oem setup then I need to try some different combos.
04-24-2012, 05:08 PM
#17
Team Owner
HHHMM, I'm an idiot for not even thinking about trying a different fluid first. My racing buddy has been pushing me to use Amsoil. Maybe I'll give that a shot. Currently I use Motul 600.
I'll try running a number of different fluids and see what happens. Perhaps it is as simple as that.
I'll try running a number of different fluids and see what happens. Perhaps it is as simple as that.
Wheel bearing can do it also.
04-24-2012, 07:01 PM
#18
Drifting
Thread Starter
04-24-2012, 07:29 PM
#20
Melting Slicks
Replace your wheel bearings and see how you make out. I can almost guarantee the condition will diminish significantly if not cure the problem all together. I have gone through the exact same issue.