BBK Info/Suggestions

[zachbooze]

Hey everyone, please let me know what big brake kits you are using, and any additional input. I am looking at Brembo, AP Racing, and PFC kits and can likely get a deal on the first two, even though I am leaning towards PFC in the performance aspect. What do you guys think? Thanks

[MOEDARE]

I'm using Brembo GT. It's a quality kit for sure, but if I were to change it would be Stoptech which I will recommend, because of the bridge on the caliper that you can remove and change pads without taking off the caliper itself. I believe APracing has a system like that aswell. I think Brembo has the more expensive replacement parts too.

[inTgr8r]

^this.

I've had Stoptech for several years and love them.
Pad changes are so easy with the removable bridge.

[Beedub]

I'm on AP all round. excellent trouble free upgrade for me.

[zachbooze]

How often do you guys track? Any reviews of how each one does on the track?

[inTgr8r]

Originally Posted by zachbooze

How often do you guys track? Any reviews of how each one does on the track?

9 times this year.
This where a BBK really shines.
I can only comment that the Stoptechs have been flawless for several years now.
I've been running Hawk DTC70 pads which seemed to be harder to modulate during trail braking after 50% wear.
Switching to PFC11 for next year

[GuidoK]

Originally Posted by MOEDARE

I'm using Brembo GT. It's a quality kit for sure, but if I were to change it would be Stoptech which I will recommend, because of the bridge on the caliper that you can remove and change pads without taking off the caliper itself.

Brembo makes a fixed bridge on a lot of their gt calipers because that makes for a stronger, better caliper. Calipers flex quite a bit under the extreme braking pressure. (calipers in race classes (like f1 etc) all have a fixed bridge (mostly several bridges) for that reason).
Less flexing lets you run a bigger pad too (the pads on your GT calipers are probably quite big, 190mm long or so? )
But you loose some ease of service. But you still have to fiddle with pushing the pistons back etc to swap pads so I wonder if it really makes it easier. Like normal brakes they dont 'just drop in', you need some sort of spreader tool that grabs all pistons at the same time I think.

as for the bbk, I'd first decide if I'd wanted a pure track bbk or a track&street bbk, in other words, whether to get a bbk with or without dust seals (without dust seals is only suitable for track imho); availability for floating discs etc.

[gmd2003]

Originally Posted by zachbooze

How often do you guys track? Any reviews of how each one does on the track?

I have the PFC Z45 355 mm front kit with 11 pads and 328 mm rear kit and their V2 floating rotors , it has excellent rigidity , is anti kick back , and has a quick change feature as well . I track around 14 days a year . Only downside to PFC is their supply . Great feel , no fade and , and always ready for more abuse .

[The Shoe]

I run Rolloface SR-C Track Setup:

8piston Front Calipers w/380mm Rotor (Stock brake dust shield trimming req'd)
6piston Rear Calipers x/356mm Rotor (Stock brake dust shield trimming req'd)
SS Lines Front & Rear
PAGID RS-29 Pads
Castrol SRF Fluid

Completely Satisfied!

More pics here: http://www.zpost.com/forums/showthread.php?t=677653

[Beedub]

nice...

8 POT / 6 POT just imo of course is just not needed at all, and is adding unneeded weight etc... id guess in reality this kit looses out on pedal feel, adds weight and performs no better than a 6/4 or even a top level 4/4 setup...

larger wheels I'm guessing are needed also..... form or function?? or am i way off???

[GuidoK]

why would 8/6 pot loose out on feel?

A manufacturer chooses for more pots if he wants to design a caliper with a bigger pad so the load is spread out.
If the same size of pads is used, more pots dont add weight imho. Just more difficult to make.

[The Shoe]

8pot calipers are generally not any bigger than a 6pot, the pistons are smaller, but the surface area is generally consistent, I say generally because every manufacturer may vary slightly. It gives better progressive feel although there are many factors in a braking system that have to be considered, main being pads. Even the stock calipers with the right pad can feel great it depends on your style of driving.

On track I like hard and fast, which is not ideal for the street especially traffic, but it depends on you the driver.

Go with what is best for your budget and ease of installation with a company that will back its product if there are any issues.

As for wheels I run 18" but my stock z4m wheels do not fit anymore.

Good luck!

[Beedub]

my experience of 8 pot callipers personally contradicts what I'm reading.... I've had a couple of vehicles with a similar setup from factory and the pedal feel has always been mushy....

[GuidoK]

You've had cars that came stock with 8 pot front/6 pot rear calipers?
What were those? pagani's and koenigseggs? Or have cheaper cars nowadays also got 8/6 caliper setup? (maybe audi RS/ merc AMG, they sometimes have quite large calipers/brake systems)

Imho the number of pistons doesn't equal the mushyness of the pedal. It's either caliper flex or pad deformation. More pots doesnt mean you move more fluid around. Also if something feels mushy, it means that there is a component in the system that has too much compliance, so either a design flaw or a worn component. Pushing more fluid around with an undersized cylinder would mean the pedal travel would be deeper but end in just as firm. Maybe the system was overassisted. If you like a firm pedal, disconnect your brake booster

[The HACK]

As long as the overall surface area of the piston on one side is the same or no more than 10% smaller than OE one piston size, the number of piston isn't really going to dramatically affect brake pedal feel. Obviously smaller overall piston size will "stiffen" the pedal and give you slightly better feedback.

The numbers of pistons on a caliper has a lot more to do with engineering a system than you all seems to think. On a larger rotor diameter with smaller sweep area, an 8 piston kit running 4 pads (2 piston per pad) can yield tremendous results in weight saving (smaller sweep area means less iron in the rotor vs. aluminum hat) without sacrificing actual friction area. But the cost to build 8 pistons is a lot more than to build a 4 piston kit, due to the more complex casting and the cost of the piston material (especially if stainless steel is used). Plus the cost to build an 8 piston kit out of, say, forged and CNC machined block of aluminum becomes prohibitively high.

But due to the shape of the spread out pistons, you can build an 8 piston caliper to accommodate oversized rotors easier than you can do it with a 4 or 6 piston caliper. That's why when you look at companies that build brake kits for racing, you'll find certain size calipers that fit a certain size brake rotors. Wilwood's website is a good example, their 4 piston kit typically only accommodate rotors up to about 350mm, while the 6 piston kit accommodate up to 380mm I believe.

Really, the numbers of pistons on a caliper is pretty low on the totem pole as the primary gauge of performance once you go past 4. Frankly, the construction (cast, forged but split in 2, or single piece forged) will have a bigger effect on the actual "performance" of the caliper than the numbers of piston past 4. If there's a solid vs bolted on bridge or no bridge will also determine the flex. From that point, the bigger the caliper, the higher likelihood of actual flex in the caliper due to the length and size become an issue.

Ultimately, it's the ROTORS that are doing the bulk of the work in converting kinetic energy into heat to slow the car down. A floating design that prevents heat from transferring to the hub, allows rotor to "float" on pins or fasteners, with open, curved vanes will do far more to keep you brakes in peak operating temp than the number of pistons in a fixed caliper will dictate. The size and the material of the rotor (carbon count if it's iron, carbon/ceramic vs. iron etc), and the frictional material will all have a bigger impact on actual braking performance than the caliper and piston count.

At the end of the day, it is the BIGGEST floating rotors with the most piston count that has equivalent piston area count to the OE master cylinder, inside monobloc CNC machined forged aluminum calipers that you can stuff under your wheels, with the pad of your choice that your money can afford that matters.

Actually the tires you use has a much larger impact than any of the above discussion, IMO. So to answer the OP's question? You can't really go wrong with ANY of those kits you're looking at. As long as the application is correct and they fit under the wheel/tire of your choice.

[Beedub]

Originally Posted by GuidoK

You've had cars that came stock with 8 pot front/6 pot rear calipers?
What were those? pagani's and koenigseggs? Or have cheaper cars nowadays also got 8/6 caliper setup? (maybe audi RS/ merc AMG, they sometimes have quite large calipers/brake systems)

Imho the number of pistons doesn't equal the mushyness of the pedal. It's either caliper flex or pad deformation. More pots doesnt mean you move more fluid around. Also if something feels mushy, it means that there is a component in the system that has too much compliance, so either a design flaw or a worn component. Pushing more fluid around with an undersized cylinder would mean the pedal travel would be deeper but end in just as firm. Maybe the system was overassisted. If you like a firm pedal, disconnect your brake booster

strange first few sentences ... , They cars were AMG models... can only state my experience with them tbh.... wasn't impressed at all....

[Finnegan]

Not much else to be said given the discussion above except to look at the cost of pads in a couple of set-up options (PFC, Hawk, etc.) and available pad options.

When I last checked 6 pot Stoptechs, for example, had a markedly higher cost than 4 pots in terms of pads. I'd bet the modulation is a bit better, but that much better given the improvement a 4 pot is in the "feel" category vs. stock? (I have ST-40 Stoptechs front and rear (4 pot), Racing Brake rotors from with Hawk Blue front and Pagid Yellow rear.)

And some rotors, given metallurgy (such as Racing Brake) require a semi-metallic pad (ceramic pads do not work). Not all pads are made for all applications.

There's a pro/con to everything, if I were to do it again I'd set up a quick comparison grid.

[zachbooze]

Thanks for the input so far everyone

[tikamak]

I have stoptech trophy ST40 fronts with race rotors (full float).
I would advise you to start with better tyres and pads, if you are past that obstacle then i recommend PFC Z45 323mm fronts (355 if you're into endurance) and PFC rotors in the rear (don't get the PFC Z29 in the rear, keep the money until you're a better driver and can get PFC Z34 in the rear)

Be sure to use the pad that you can modulate the best