Brakes upgrade questions; 8-pistons in the rear?

[thatonedude]

I've been trying to figure something out, big brake kits come with a rediculous number of options. Theres the 4-piston, 6-piston, and 8-pistons for the front but the rears all stay at 4-piston. Whats the reason for this? Or, are there 8-piston rear dist brakes too?

Whats the best and for why, slotted or cross drilled?

Whats important when you upgrade your brakes, should you go all out and get the best or just something for now?

I know this will come down to what my car build will be and my intentions, so for the one I'm trying to build now is to be built for the track on the weekends. But, I also want to get some significant power out of my daily driver 325ci too which will also need all the upgrades. So I;d appreciate tips, input, and links to brake tips. But, I have tried to get some info and found quite about this but not so much about the reasons that rear brakes dont have 8-pistons. Although really minor I'mstill curious.

[DomM3]

Ok I try to scratch all my english together.
Normaly is to take 4-6-8 piston in front and 4-6 piston in the rear.
The reason is the break force in front is round about 70% and in the rear 30%
Then you need in front a bigger diameter from your brake disc and a bigger or stronger caliper.
In the rear the break force is 30% and you need a smaller diamter from your disc.
There's no point in that to use a 8 piston in the rear.
And a 8 piston don't fit at the rear holder.
But you need to know, when the break force is to big or to strong your car
gets lighter in the rear.
The rear will be anxious and nervous.
The proportion is important.
In front 6 piston and rear 4, or in front 8 piston and rear 6.

Puh, sehr angstrengend. In Deutsch wäre es einfacher.

[Manolito]

My uninformed opinion - more than 4 pistons front and two rear is just a marketing gimmick, like a shaver with six blades instead of 4 or 2. The second blade gets you something. After that, its a gimmick.

The key question with brakes is what are you doing with the car? That determines the pads you need, and the pads tend to drive your rotor choice. The cheap PBR delux organics I use on my commuter car are perfect for that application, but I would not dream of using them on a tight race track where the brakes have to work even when the rotors are glowing red hot. Similarly, the pads I would race with would be a PITA on my commuter car.

Slotted and drilled rotors evacuate water better and theoretically dissipate heat better. Drilled rotors have a nasty habit of cracking. I don't use either one on any of my cars at the moment. Opinions and applications vary.

Big rotors are great for feel and stopping power, but remember, the bigger the rotor, the more it is dependent on air flow to cool. It can't dissipate heat as well into the wheel and the hub. Make sure you are getting air to those big rotors.

As noted in a previous post - front/rear balance is CRITICAL if your goal is to keep the car between the headlights and taillights. Buy brakes that were designed to work together as a set on your car. Do not buy front and rear brakes independently.

[DomM3]

For the street I would prefer other pads from EBC, EBC yellow stuff, or Hawk
pads, Flex pipes an another brake fluid.
You feel the different.
We use for tracks, Nordschleife, slotted discs, EBC yellow stuff in front, and EBC red stuff in the rear. 6 piston in front and 4 piston in the rear.
Slotted are he better discs than the drilled.
The problem with the drilled discs is the crakcing between the holes.
The question is how to use your car.
8 piston in front is not a gimmick. For powerful cars like a Ferrari, or Lambo is this better.

[Manolito]

OK, I'll take your word for what works well on the Italian exotics. I don't travel in those circles.

"Work like no one is watching.
Dance like you've been hurt.
Love like you need the money"