Thanks larry, seems you know your stuff very well and that was very helpful. Its also not that I want to spend too much but rather that much ($4,500). And I do want the look for the rear but if I have to I will compromise.

 

Again, thanks..great info. So my next question is this, can I go to 12-13 in rotors and decrease my stop time? I really like the look of drilled/slotted rotors. Could the C5 upgrade be enough to give me the proformance I want? It seems with every answear I get more questions...thats how you learn though. Again, thanks EVERYONE and thanks everyone in advance too.

 

The problems with crossdrilled rotors is in the process of adding the holes. Extreme braking generates a tremendous amount of heat. That heat can easily cause cracking in cheap drilled rotors where the holes are drilled after the casting process. The higher-end rotors that have the holes made as part of the casting process will withstand the heat much better. The final finishing process does not change the metal structure so these rotor are not a prone to cracking.

The holes by themselves do not really provide a lot of extra cooling. The loss of surface area on the rotor from the holes can actually increase the amount of heat generated.

Brake cooling ductwork that takes air from the front of the car and points it at the center of the rotor provides much more cooling. The airflow through the rotor vanes does a lot more to cool compared to just holes across the body of the rotor. Any dedicated track car will have cooling ducts to keep the brakes as cool as possible.

IMHO, ceramic pads do not have as good of braking power compared to semi-metallic pads. They do last longer and don't dust anywhere near as much, but compared to some performance pads, the stopping power is not there. Install a set of Hawk HPS (High Performance Street) pads and you will see a big difference.

Bigger rotors will provide better braking force though less fade and the larger swept area of the rotor as CentralCoaster mentioned. Without ABS, braking perfromance will be no better than the ability of the tires to stop the car without sliding. Once the brakes lock up, the tires slide and you will not stop as quick or as short regardless of the size or power of the braking system.

The trick will be to know how hard to press on the brake pedal to get the most stopping power which is just at the point of wheel lock-up. This takes some experience to do. There are race drivers who can stop quicker and in shorter distances that ABS-equipped cars simply because they "know" how much pressure to exert on the brakes and where the point is that the tire will just begin to lock up. That's the most effective point in a brake system's stopping power.

Of course the tires play a role in stoppping. Tread compound and road surface have big roles in stopping ability. A soft tire compound will stop quiicker compared to a harder tire. The road surface plays a part in how the tire grips the road too. Get any sort of loose material (gravel) or even moisture on the surface and stopping distances can change drastically.

 

Absolutely. Go with the C5 or J55 front kit, then put some high performance pads on front and rear, turn or replace your stock rear rotors, install DRM's bias spring, and follow the pad mfgr's brake bedding procedure.

I'm not sure how optimal the DRM bias spring is, or if an even stiffer one is better for the C5 upgrade, I'm still figuring that out. But the DRM spring is a guaranteed improvement over stock.

 

Thanks, now I have a question about the spring, what role does it play in all of this and also could the proportioning valve be changed to help the times? TIA

 

The proportioning (and some other stuff) is actually done by a combination valve that's builtin to the master cylinder. The DRM bias spring is stiffer, so it doesn't reduce pressure to the rear brakes as much as the stock unit.

There's more to it than that which is beyond this thread, but basically the % of rear braking changes depending on how much force you put on the pedal, unlike a true proportioning valve or tandem master cylinders, which puts out a fixed bias ratio, and is not optimal for street use and pad wear.

 

Ok, see I did not know that the proportioning valve was built into it. This is some great stuff. Your teaching me alot of need 2 know stuff. I know more now than I did and still trying to figure out what would be best. My two big things are the looks of the rotors and proformance. I guess we'll see what happens as I research it all out.

 

The ceramic pads were as good as EBC Greenstuff for me without the dust. why are all the new race cars going with ceramic rotors then? These are forged drilled rotors. The 20 holes don't mean that much surface area and keep them cooler.

 

If The Rears Lock Before The Fronts You Crash.

If The Rears Lock Before The Fronts You Crash..

If The Rears Lock Before The Fronts You Crash...

 

A motorcycle has a way higher center of gravity so it can't use much rear brake.

CG and f/r weight has everything to do with bias, rear engined porshes have a huge advantage here.

 

If the rears lock up going into a corner, you crash.

If the rears lock up going into a corner, you crash.

If the rears lock up going into a corner, you crash.


Ever watch a NASCrash race at Martinsville or Bristol? Ever watch the Rolex 24? Too much rear bias = wreck!

There's a reason the manufacturers put smaller rotor one pot brakes on the rear. It's so the cars don't crash.

 

I have a C4 - J55 13" brakes for sale. Includes

2- J55 caliper brackets
2- calipers
2- drilled/slotted rotors (5,500 California miles)
1- set of new pads (in the box)

$200

send me an E-mail

 

 

No, they put smaller rotors on the rear because they don't need as much heat handling capacity back there. They use the smallest brakes that will do the job without fading, because they want to cut down on rotating weight. Compare Talladega brakes with Martinsville brakes.

The bias can be optimized no matter how many pistons you have or how big the rotor is. Anyone who upsizes the rear rotors or caliper pistons in order to get more rear bias is wasting their money.

 

I need to chime in here and ask the most basic of questions:

red johnny, tell us exactly what you want out of your brakes. Be honest, this thread will get to your answer a lot more quickly if you are honest about what matters to you...Lots of guys on here ask about brakes and try to hide that fact that looks may be an important factor. You're going to get a few guys that rip on you for wanting "cool looking" brakes, but who cares?

You keep saying "stopping time." I don't know what you mean by that. The most common brake performance terms are distance and fade. And keep in mind this refers to all out panic braking, not day to day driving. Are you ever really doing that? How comfortable are you with threshold braking (keeping the pedal at the absolute limit of brake friction without inducing lockup)?

I can give you a very simple system that will increase your stopping distance, but it will coat your wheels with dust and squeal like a school bus at every stoplight. In addition, you pick a pad that has great initial bite characteristics at ambient temps and it will fade with repeated hard stops.

If I told you to get a set of my race pads, you'd hate them because they feel like crap and don't give controllable grip until they get nice and hot.

So...please rank the following items in a rough order of what's most important:

1. Cost
2. Appearance
3. Absolute stopping power
4. Fade resistance
5. Dust emittance
6. Noise or squeal
7. Street or track / Auto-X use

This will help us narrow your answer down immensely.

My guess is you want better performance, minimal loss of street manners, a nice appearance upgrade, and are willing to spend up to $1000 to get what you want. Am I close?

Check out www.porterfield-brakes.com. They have an extensive list of brake pads from several manufacturers (Porterfield, Performance Friction, Raybestos, Hawk, etc) with a nice description of each pad's characteristics. Look in the drop down menu under "brake pads," it's kind of a small link. There is a TON of great information. Pick a few pads that sound like what you want and then ask here if anyone has personal experience with those two or three to make your final decision.

For street, most like the Hawk HPS (stay away from the HP+, they squeal like a stuck pig and will turn your wheels black in two days) and the Performance Friction Z pads.

 

ScaryFast your right "My guess is you want better performance, minimal loss of street manners, a nice appearance upgrade, and are willing to spend up to $1000 to get what you want"
Heres the list in order: 3, 2, 1, 5, 6, 4, 7

Ok, that example I had given about snow driveing...it was just that...AN EXAMPLE. I did not mean it for a refferance as to what I am looking for. My whole point for that story was that I did not apply much brake and my fronts locked before they should have. I now understand that rear braking power should only account for a certain % of total brakeing.

ATTN: Thanks everyone for making this thread so very informative!!

 

Good thread...I learned something too

 

I am NOT a brake expert and I am learning as much from these posts as are many of us. I am however quite experienced in driving in the snow having spent more than 40 years in New England. Having larger disks in the rear of your Camaro would not have prevented that skid from happening. Front weight transfer in the snow is very dificult to overcome unless you actually run 4 studed snow tires on your car (which will only really work if you have a front wheel drive vehicle) which is what I did for many years and you are not in the process of applying the brakes during the turn itself.

As to holes drilled in disks causing cracks, I always thought that the cracking was solved only by chamfering (sorry for the misspell) the edge of the drilled hole thus releiving the stress placed in the metal by the drilling process. This is quite labor intensive and thus quite expensive to do.

 

AGAIN it was an example....I am not trying to overcome snow driveing I do that myself very well. Anyway, no one bothered to ask what caused the problem for that situation..the answear was a bad proportioning valve which was putting all the juice to the front so the fronts locked up fast and the backs barely worked. But thanks for the input Mr Peabody I do see your point.

 

For less than a grand you should be able to do the C5 upgrade. I don't know for sure that it's an easy bolt-on for the early C4's, but I know a lot of guys do it to the later ones.

In addition, there are a lot of rotor options available for the C5, you can get slotted or drilled rotors from a number of suppliers, Power Slot comes to mind. Or, the stock Napa rotors are cheap as hell, around $25.

Also get some steel braided lines. The Goodrich product is less than $200 and will translate into a stiffer pedal feel as they will not bulge under pedal pressure like rubber lines will. Try changing your fluid, too. There are a number of threads out there on which fluid to use, do a quick search on this or the road racing forum.

For the rear, you should be able to move your front kit (or a '92-96 front PBR caliber) to the rear with only a bracket change. I haven't reasearched it, so I don't know if the brackets are easy to find or if you need to get a set made. However, a lot of people upgrade the fronts and then move the fronts to the rear. You still get a bigger rear disc and 2 piston caliper, but the cost is low and you won't upset your brake balance.

There are a number of front kits out there in the $1500-$2500 range, much cheaper than the Wilwood kit you mentioned with great performance. I have a Brembo set-up in the front and my old front brakes moved to the back.