I know, this thread was probablly hit up before but I did my search and could not find the answear. Anyway, I am looking to upgrade my front AND rear brakes to drilled and slotted rotors and bigger calipers. I want 13" all around for the uniform look. Here is what I found so far and I dont like em.
I like the wilwood WSB-001 but I aint ready to pay $4,500 for them.
http://www.dougrippie.com/drm/brake_conversions.htm
These are nice but I dunno if they are front and rear.
http://www.streetortrack.com/baer-br...body-front.asp
Then I found these which are cool but they are only for the front
http://www.jdcorvette.com/specials.htm

Anyone got something closer to what I am trying to do...cause it doesnt make any sence to me to just upgrade the front and not the rear. I know that its like 80% stopping powers in the front but I want the rear to have a powerful 20%.

 

Guess everyone is tired of discussing brakes...maybe alittle run out? I used the search, and I really did not see anything that suits what I am looking to do. I have to balance out the rest of my vette since I already have the following upgraded: engine , transmission, rims and tires, suspension, lowered and the next step in my mind before I add more power is the brakes.

 

Ok, what year is yours? The Zr1 use 13" front (with twin piston calibers) 12" rear, then I think it was 95 GM went to that as standard. Can't see any possilbe reason for 13" on the rear. Drilled and slotted rotors don't help you stop, they are strictly for show. I have 95 with 13" front and 12" rear and running Bosch ceramic pads. I can lock it down at any speed and throw passenger thru the windshield while stopping dead straight and smooth.
Plus I get no brake dust on my rims. Only if you autox on a regular basis would you need anything more.

 

What year is your car?

And do you want it to look good, or stop good? or both?

 

How did you come up with they are only for show? From what I have been reading for the last 2 years on them they work well grabbing the pads. Maybe you could show me an article to prove your point? Oh yeah, its a 85 and the reason I want 13 in the rear is for uniformity. I think I will go with those ceramic pads though. I have been reading up on them and found nothing but good about them.

 

Its a 85 and I want both. Trying to go for the red calipers to match my vette but I really want something that performs well also so the red isnt as much as an issue as the performance peice.

 

Take a look at a motorcycle. All the braking is on the front wheel. My bike has two large brakes on the front with 4 poston calipers, small brake on the rear with2 poston calipers. But hay it's you car and I would do what I wanted to do.

 

Yeah I know. But I keep thinking back to the winter of 2000 when I had my camaro. There was about 6 inches of snow on the road and I was going about 5-7 MPH when I was about to make a turn...long story short, I hit the brakes gently and the front locked up and skid while the back were not really doing anything, due to the front locking up and skidding I hit another car. No real damage but the morale of the story is I dont trust to have all my brakeing power in the front. I would perfer a 50-50 system but I am pretty sure they dont make it and there are probablly reasons behind that. All I am saying is if my front were to lock up again I would know that my back are working just as hard also. Your right too painter man, its my car and I will do what I want. I WILL be putting on 13" rotors on the front AND back but I am not saying that for example: I have to have 4 piston in the front and 4 in the rear. I am open to having 4 in the front and 2 in the rear. I dont want a single piston in the rear though. It has to be 2 or better. I feel like I am about to shoot myself in the leg cause I know this is going to start some stuff with someone as they ALWAYS have a better way (not that its a bad thing) If you do have something to add to help me out please feel free and give me that knowledge. TIA

 

The braking system has what's called a "proportioning valve". It regulates brake line pressure to the front and rear calipers. The braking system is designed to have more braking power in front than at the rear. This primarily because when the brakes are applied, there is a shift of weight to the front of the car (weight transfer). Think of what you feel as you hit the brakes; you move forward in the seat. You also notice that the front of the car drops downward. That weight transfer also takes weight off the rear of the car.

So the proportioning valve reduces the brake pressure at the rear of the car because the rear brakes don't need the same level of stopping power as the fronts. That's also why the rear brakes are physically smaller than the front brakes.

With your car being an 85, you don't have ABS so getting a good brake package doesn't mean a lot if you cannot effectively balance a high-performance braking system. Going to physically large rotors will be an issue as the mounting hardware is really only available with the high-end brake packages.

Going to 13" rotors even in the front will require new wheels to clear the larger calipers. The 85 wheels have different offsets compared to the later C4's that came with 17" wheels.

Unlesss you are building a dedicated track (road race) car, multi-piston calipers are really overkill unless you want the "look".

I would recommend going to a C5 front brake setup and leave the rear brakes as they are. You may have a hard time finding bigger caliper brackets for the rears anyway. You can use drilled and/or slotted rotors but keep in mind that the cheapie drilled rotors will crack eventually. These cheap rotors have the holes drilled after the rotor is cast. The drilling stresses the metal and when the rotor gets hot from extreme braking activity, stress cracks will form around the holes.

For street use, they can work OK but if you intend to do any number of track days with the car, either run stock rotors or get a good rotor like Baer or Wildwood. They are expensive and they will wear so expect to budget a lot for brakes if you track the car.

Have you tried a set of good high-performance pads and new rotors yet?? There is a good selection of HP pads available that will make a big difference in braking performance. I use Hawk HP+ pads on my 87 autocross and track day car and the increase in braking power is tremendous even with using stock rotors. They work fine for street driving but they do dust a fair amount. That's a price to pay for using HP pads but when the front pads only cost about $75, it's a lot better than thousands of dollars for a system that may only give me another 15-20% improvement and still need occasional replacement parts.

Don't worry about the color of the calipers. There are caliper painting kits available that will give you a choice of colors. And brake dust will eventually cover the paint so it's more of a headache keeping them clean. And most race cars don't have painted calipers. To a degree, the paint covering will keep the caliper from transferring some heat out of the metal.

 

From what I remember on the subject, 85's are not easily converted at the rear. I may be mistaken but 85' uses a drum type system for the handbrake; later l98s have the handrake integral with the disc portion of the rear brake...I think. So you would have to upgrade all hardware including caliper and possibly the handbrake cable. I would guess gm didn't make the handbrake lever assy compatible with the cable either. Good luck and avoid drinking as much coffee as I did this morning.

 

First off, thanks everyone for your imput so far. I do know about the proportioning valve and its purpose, I did not think all the way through about the weight transfer and the brake system. I do have room for the larger rotors as I do have 17's in the front and 18's in the rear. I am going to go for a good quality set of rotors and I am going to use ceramic pads. I would like to upgrade the rears to at least what I have up front. I am pretty far out yet for this project but I allways research when possible so as to make the best choice when the time comes. I do have disk in the back and I am not too sure how the e brake hooks into the system. I will have to check it out as that definately effects how I am going to do this.

 

I have Hawk HP's on all four wheels for well over a year now. Big difference in stopping power. I've never driven in snow with them so I can't comment there. But in wet or dry weather with my Firestone wide ovals I can stop on a dime. When I changed them I used a wire brush on the end of a drill on the calipers. They came out as a nice looking silver color and they still look good today. No dust on them and it's a daily driver. The rims tend to get dust weekly. But thats just about unavoidable for a daily driver no matter what type of pads you use. Good luck with the brake upgrade. If you change your mind maybe look for a 95 or 96 system with 13" in front and 12" in back.

 

You got a link for the hawks?

 

There are no ceramic pads for the stock 85 brakes. I'd recommend Hawk HPS, or HP+, haven't used them, but they get great reviews.

Brake bias sucks from the factory, the rears don't do squat. Upgrading to 13" front C5 brakes will make your bias a little worse, and unless you are roadracing the car, you don't need the extra heat capacity they provide. (also too much front bias will just use up this extra heat capacity). Stock fronts will work absolutely great for autoX and street, I doubt you've found the limits of them yet.

Best performance per dollar = Keep stock calipers, Hawk HPS all around, turn or replace the rotors, fluid flush, $12 doug rippie bias spring (absolute must have), and break em in properly.

Consider the C5 upgrade (~$500) a cosmetic one for what you use it for.

There are no cheap bolt on upgrades for the rear brakes. I haven't gotten around to designing my 13" rotor upgrade using 88+ rear calipers yet, because the rotors and hats are going to cost $500 initially, and the extra rotor isn't necessary except for looks. The later stock rear rotors are only 12", so upgrading from 11.5" is a waste of time for looks, as it also requires custom brackets.

 

I dont see how upgradeing to 13" rotors WOULDnt make a differance. Everything I have read about brakes states that if you get bigger rotors you get better stopping power. Also, what is brake bias? I know your trying to help but I am really trying to see a huge differance. TIA

 

I think this may be where I ordered mine from. I got the Hawk HPS for less dust. HP+ is for autocross I believe. http://www.raceshopper.com/index.shtml

Here is another with rotors but may not fit yours. http://www.vbandp.com/detail.aspx?ID=841

Or here is the corvetteforum store with conversion kits and pads.http://www.zip-products.com/Corvette...F7C0F6AB29E66C

Heres the Hawk HPS's on ebay. http://stores.ebay.com/Gripforce-Bra...dZ2QQpZ2QQtZkm

 

Thanks, I will check these out.

 

Look at it this way: rear brake power is more dependant on tire traction than on rotor size. Weight transfer during hard braking means it doesn't take a very powerful rear brake to overcome tire traction.
If you want "the look", then that's a different matter...

Brake bias is the proportion, front-to-rear, of pad-to-rotor friction. It is dependant on line pressure, caliper piston area, rotor diameter, pad makeup, etc.

You won't see a huge difference in rear brake performance, because (see above) tire performance is usually the limiting factor in rear braking.

Keep doing your homework; contacting vendors of brake systems, etc. and you'll find what you are looking for. Just listen to the others (such as CentralCoaster, who makes it a point to find out facts), they know a few things....which is why you came here in the first place, right?

If you aren't willing to compromise on what you want in a brake system, then be prepared to part with some $$. I know you said you liked the wilwood system but didn't want to pay that much.....well, guess what?
One doesn't find himself a Corvette owner very long before one finds out that it ain't the cheapest hobby around. And especially in the way of mods, expensive tastes are just that; expensive.

Good luck and let us know what you decide on.

Larry
code5coupe

 

Great brake thread. I want to chime in and diagree about crossdrilled rotors. They have to cool quicker. The physics of the vanes blowing air through them must produce cooler temps.

My Raybestos setup with ceramics work better than stock. Have you tried them for pads? Quiet Stop is the brand.

 

I haven't seen any comparisons of a refreshed/new 84-87 system to a C5 upgrade. Also, don't pay attention to anything you read on those upgrading from 88-96 brakes because it doesn't apply.

Bigger rotors give you more heat capacity = more fade resistance.

Bigger front rotors & pistons give you more leverage up front = needs less pedal force. Your "seat of the pants" feeling will tell you this shortens your stopping distances, but it doesn't.

What it does do, is prevents you from putting as much force to the rear brakes, meaning the rears do less work, and the fronts do more. This cuts into that extra fade capacity you gained up front.

I put a Wilwood brake kit on the front of my 85 (the rotors and piston area is slightly more than the C5 brakes), and as expected, the 60-0mph stopping distances turned to crap. (126ft to ~145ft) The fronts would lock up too soon, and the rears would do almost nothing. Yet the seat of the pants feel was good, the pedal was solid, and didn't take as much force to lock up the brakes. After this, I dialed in way more rear bias, with no other changes, and pulled several 60-0 stops in 115-120 feet.

Increasing rotor sizes without looking at the rest of the engineered system will usually hurt your stopping distances if you're comparing new components to new components. Lots of people on here say, "my Corvette brakes suck, my daily driver import stops better!" Then they spend a bunch of money on a 13" rotor upgrade, never considering that their import has 9" rotors on it and their stock vette brakes weren't even in proper working order.