CaysE

Just want to add something about the 2- vs 4,6-piston argument. I can't say I know as much about brakes as you guys (yet ), but I would think that 2-piston is all you would need on the street, cause if you were to use the full force of the 4,6-pistons, you'd be skidding all over the place way before you would be with the 2-piston. you can use more braking power on the track because you have tires that can still grip the road at extreme push (acceleration) and pull (braking), hence the use of more pistons. As far as brake feel and which ones can stop better on the street, I'd say it's a moot point; you can always adjust. I can get my stock brakes to skid my tires if I slam them hard enough, so I'd say it all depends on the tires, really.

Like I said, I don't know a lot about braking systems, and I'm talking non-ABS here. Hopefully noone comes raining flames on me; to me it just seems like logical sense. Correct me if I'm wrong, but I'd say a well tuned stock brake setup could stop as well as any aftermarket 2- 4- or 6-piston setup on the same street tires.

AGood2.8

To a certain degree you are correct with your statement that You only need so big for street use.

Let me clarify how and why bigger calipers are better and this will give understanding as to why they may or may not be needed.

Above you ask about caliper size (i.e.-2piston,4, or 6) With larger 6-piston calipers, its not the extra force given by having more pistons that make them better- heck, you want more force with your 2 piston calipers, then just step on the pedal harder. What 4 and 6 piston calipers provide in the way of performance is the use of larger brake pads consecutively.

Why is that good- basic fact that larger surface contact area will provide more friction or stopping power. More sq cm area of pad surface provides a more distributed friction area and thus provides more control and a broader heat distribution area maintaining more constant predictable temperatures and friction force - basically,better pedal feel.(sweet spot)

AP calipers for example run aprox 75 sq. cm pads in their 6 piston calipers and aprox. 60sq. cm pads in their 4 piston calipers. What the extra pistons do (And do only) IS TO PROVIDE EVEN DISTRIBUTION OF HYDROLIC FORCE ONTO THE BACK OF THE PADS (I capitalized that part because of its importance). The larger the pad surface cotact area to the rotor, the larger the piston to pad contact area needs to be on the backing plate of the pads.

Pad backing plate pressure- Take a pad that is 2" tall and 6" long.
Now place one two inch diameter piston centered on its backing plate and you will have strong force in the center of the pad and faded friction ratings at the ends. Now take 3-2" pistons against it (this isn't good either) and you will raise the force of the ends ofthe pads but cause too much bite and uneven fprce on the ends of the pads and less pressure in the center. 6-piston calipers are developed to apply even pad pressure across the entie pad backing plate so the pad will make even contact with the rotor- hence the use of 3 different size pistons on one 6-piston caliper- its not for more pressure, its for even pressure of larger pads.

2-piston calipers run mostly the same size pads as 4-piston calipers but only apply pressure from one side of the caliper- causing the 2-piston caliper to have to "float" more distance on the guide pins to apply pressure. 2-piston calipers thus do not function as smooth as 4 or 6 piston calipers do because the entire caliper has to move for the pads to make contact with the rotor.

Getting to the level of 4 and 6 piston calipers is really not nessesary for street use because these factors above don't come into play as much until higher racing temps come into play- these temps are not commonly reached on a street vehicle unless you see track time and experience your great street brakes leave you in a hurry.

P.s extra pad surface area also provdes longer life of pads- needed for extreme racing use but not for street light track.

CaysE

Wow, good explanation. Thanks for informing a brakes newb. So it looks like 2-piston calipers are plenty for street use, but I know a few of us like to get into the occassional street race, so perhaps 4-piston calipers would be best for street/strip setups.

Again, correct if I'm wrong.

Kandied91z

iTrader: (7)

you will be more than fine with 2.

if you road race or have money to burn then jump to the 4.

CamaroMike

Just thought I would get an interesting point across. I have by no means read this entire thread but I just got off the phone with Bear and "Bill" in Sales/Technical has a couple interesting points. "Bill" assures me that the cross drilling and slotting is not only cosmetic but causes stress risers in hard driving situations, which eventually lead to severe rotor cracking. I have personally witnessed this on a Z06 Corvette that I fix regularly at work. Another good point brought to my attention is that in Bears testing the 12" kit for our cars stops just as good as the 13" kit. There is theoretically an advantage to the 13" brakes but in testing there is none, most likely due to the adhesive limitations of the tires. If you can lock up the brakes consistently without pedal fade then bigger isn’t better. At the most it is reduced pedal effort. Just some thoughts for ya, not trying to stir the shizneot.

ozzga

from what i've read, cross drilling can cause weak spots and crack the rotors. however there are different methods of drilling - some companys will just drill the rotors, but others are cast with the holes already in them. the second method is stronger. the holes are supposed to allow vapors emmited by the pads during very high heat use to escape instead of making a layer between the pad and rotor, reducing friction. but i'm not even sure if the newer pads out there today still do this. for sure on the street it is completly unnessary (even dangerous), but sure looks cool

slotting however helps to wipe the pads and make them wear more evenly, and is of some benfit on a street car. dunno how much it affects the structural integrity of the rotors though.

iroc22

Well the reason I asked was because I am trying to find something that I can use that was a factory piece and will work with my 88 4 wheel disc setup (if thats even possible!) because I can get replacement parts at a cheap price. The 1LE might end up being the way to go since I can get factory parts for cheap. I have skills and welder buddies so I dont see that being the problem.....

What about the C5 calipers and or rotors? have any experience with them?

Kandied91z

iTrader: (7)

i have my gm parts cross drilled/slotted rotors that have worked very well on my 91 disc setup. i highly recommend them for those who want something reliable and not spend the money on a custom setup.