C4 race brakes
Thread Starter
Pro
Joined: Jul 2007
Posts: 670
Likes: 0
From: Culver City California
C4 race brakes
Hello everyone, I was wondering what everyone here does that has a C4 full race track car and needs better braking and pedal modulation than a weak two piston C5 Z06 caliper conversion can provide. I am going to have to do my brakes soon and I am running J55's right now. They will not cut it for severe track use though. Wheel size is not an issue as I will most likely be running 18x11.5 CCW on all four corners. I am not against staying with a 13 inch rotor and ZR1 rims but I want to move up to a better stiffer caliper (four or six piston). Does anyone make a bracket to adapt the more popular four or six piston calipers (wilwood SL6,SL4 stoptech ST-60, ST-40 ect...) to a C4 spindle. rear would be nice as well. I have searched around but i've come up short! thanks
Burning Brakes
Joined: Sep 2005
Posts: 993
Likes: 3
From: Iowa
Not that I know of; most guys have parts fabricated to make a switch like this. Another thing to consider is the bearing life of the hubs; many guys want to get away from the stock units since they don't deal well with the temps that they see at the track. Sorry I can't be of any more help; I personally like the Wilwood Integra Radial mount calipers but have never seen them fit up on a vette.
Le Mans Master
Joined: Aug 2002
Posts: 6,080
Likes: 3
From: Clearwater FL
St. Jude Donor '06
I'd ask in the roadrace section too(if you haven't already done it). Those guys deal with this problem quite a bit. I haven't heard of using the same rotors with the wilwoods or stoptechs. Seems like the stock rotor would be the weak link especially in a severe roadrace environment you talk of. You can get pretty good performance from a Upgraded C5 system with better rotors and aggrevive pads if the $ is an issue.
Safety Car
Joined: May 2003
Posts: 4,283
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From: Houston Texas
Pro
Joined: Jan 2003
Posts: 664
Likes: 119
From: Albany OR
Revolution brakes http://www.revolutionbrake.com/ (formerly Precision Brakes) offers Wilwood brake kits for all years of C4 Corvettes, both front and rear kits. I used one of their front kits on my 85 track car. Works well for me. Another option for you to check out.
Brian
Brian
Le Mans Master
Joined: Mar 2001
Posts: 7,999
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From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
Cruise-In III Veteran
Cruise-In IV Veteran
St. Jude Donor '12
PM bluewasp, he had some awesome brakes on his GS.
It was crazy expensive, but stopped on a dime and gave you 9.5 cents change.
So far I'm happy with my J55's on the track, more horsepower is on tap for next year though so I may need to upgrade.
It was crazy expensive, but stopped on a dime and gave you 9.5 cents change.
So far I'm happy with my J55's on the track, more horsepower is on tap for next year though so I may need to upgrade.
Racer
Joined: Feb 2005
Posts: 278
Likes: 4
From: Havre de Grace, Maryland
I wouldn't be so quick to disregard the C5 conversion. The performance upgrade over the J55 setup is significant and the cost is minimal when compared to upgrading to StopTech or Willwoods. With a good set of pads (I currently run Wilwood Hs, but I've also run Carbotech XP-12s) I can stop with the best of 'em and the rotors are fairly inexpensive. Make sure you have proper ducting, however, or all is for naught! As an HPDE instructor, I run about two weekends a month.
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Advanced
Joined: Feb 2008
Posts: 98
Likes: 0
From: Southlake Texas
I also have the ZO6 C5 conversion on my track car and think it is the best unless you have unlimited funds. If so, then the folks at http://www.revolutionbrake.com/ have everything you desire.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
You need to define what exactly you're using the car for.
If it's for Open Track days, HPDEs, or NASA Time Trials, the J55 setup with adequate cooling and track pads is fine.
If you're really going door-to-door racing, the answer may different than above depending on race length, series rules, etc.
If you're looking for better modulation, then you need to address the system not just the calipers and rotors...ie don't forget about the master cylinder.
If it's for Open Track days, HPDEs, or NASA Time Trials, the J55 setup with adequate cooling and track pads is fine.
If you're really going door-to-door racing, the answer may different than above depending on race length, series rules, etc.
If you're looking for better modulation, then you need to address the system not just the calipers and rotors...ie don't forget about the master cylinder.
Pro
Joined: Apr 2005
Posts: 590
Likes: 0
From: Boynton Beach, FL
I wouldn't be so quick to disregard the C5 conversion. The performance upgrade over the J55 setup is significant and the cost is minimal when compared to upgrading to StopTech or Willwoods. With a good set of pads (I currently run Wilwood Hs, but I've also run Carbotech XP-12s) I can stop with the best of 'em and the rotors are fairly inexpensive. Make sure you have proper ducting, however, or all is for naught! As an HPDE instructor, I run about two weekends a month.
In summary;
1) The boot seals on the C5 calipers cooked in the first two minutes on track.
2) The C5 calipers clam shelled so badly the brake pads would taper so that the rear of the pad was on metal while the front still had half the lining left.
3) The factory rotors would check and crack so badly I had to check them after every session. If you had to come in without a cool down lap the rotors would crack in the pits after heat soaking. I even tried prototype GM racing rotors. I got the P/N from the GM Corvette racing team. Same problem.
The set up is cheaper than Wilwood but if I had kept the car upgraded brakes were a next step must. my $.02
Larry
Pro
Joined: Apr 2005
Posts: 590
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From: Boynton Beach, FL
I don't have the P/N but it came out of a 93 F body Camaro. Its a bit of work to install. I used a C5 fluid reservoir that bolts on. The Front and rear brake line outlets are reversed (front to rear) and the fittings are not the same size. When you get the cylinder get the fittings at the same time. You have to cut and splice the factory brake lines. I got the cylinder at a junk yard and cut the lines to get the fittings. The mounting braket holes have to be opened a little but it fits. Now that I think about it I had to modify the piston cylinder. I had to drill it deeper. If your really up to the task I think I still have all the details at home. I might be able to scan the sheet in my log book. Let me know.
Larry
Larry
Le Mans Master
Joined: Jul 2004
Posts: 9,835
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From: In front of C6s.
St: Jude Donor '10
100%. I will be going with the Movit brakes once I recover from my engine build for the track car. They may be $$$, but their longevity and stopping ability are phenomenal.
Race Director
Joined: Jun 2004
Posts: 13,960
Likes: 707
From: WI
Ya had me till drilling the M/C! 
The brakes are working OK now but I was wondering if the Camero M/C would help with the initial bite. I have found there is longer pedal travel pressing the pedal just once. If I press the pedal twice in a row the pedal travels a little less, not a large amount but noticable. I was thinking this was an issue with the booster. I don't like this to well because the pedal feels different braking after a long straight then it does braking in a series of turns.
The brakes are working OK now but I was wondering if the Camero M/C would help with the initial bite. I have found there is longer pedal travel pressing the pedal just once. If I press the pedal twice in a row the pedal travels a little less, not a large amount but noticable. I was thinking this was an issue with the booster. I don't like this to well because the pedal feels different braking after a long straight then it does braking in a series of turns.
Melting Slicks
Joined: Jun 2004
Posts: 3,253
Likes: 2
From: Castro Valley CA
It is poor economics to save money on the brakes, I know, I run J55's(C5's are marginally better), spread calipers, prematurely destroyed pads, cracked rotors, expensive lost track time. it is tough enough out there for any C4 with C6Z06's running around, let alone trying to pussyfoot around under braking to make them last. The most fun you can have with a C4 is to divebomb cars 5X as expensive under braking, which you can easily do with lesser brakes and the right pads for 2 or 3 laps before they melt. Powerful brakes that are consistant and will last 5 twenty minute sessions are exactly what you need. If you ever venture up north and run Laguna Seca with anything less than top notch brakes, you will regret not taking the advice of some of the forum members including myself. You don't need to waste your money on the rear calipers as others have said, they are fine. Smart move on the 18 x 11.5(are you sure 12's are not an option) wheels all around, I presume you plan on running 305/30's or better yet slicks all around. The trick to running a C4 against newer, sophisticated high dollar cars are big super sticky tires and top notch brakes, more than likely you will be outhorsepowered. You will need to carry a lot of corner speed and brake late, that is my strategy.
Race Director
Joined: Feb 2001
Posts: 13,911
Likes: 101
From: Manassas VA
NoVa Events Coordinator
St. Jude Donor '14
They have a 304x32 mm kit for the 84-87 that will work. if you have 88+ i'll see what I can find on the website.
Last edited by Bluewasp; Mar 11, 2008 at 10:49 AM.
