There seems to be very little accurate information floating around the internet on racing brakes (aka BBK's). Why upgrade? What should I look for? What's important and what's popular opinion? I'm here to help you figure this all out.
What's important? Reliability, light weight, caliper stiffness, pad size and compound availability. First off if you are driving on the street you will realize no benefits of a BBK. Sorry to say so, but it's the truth.
BBK's really only help dealing with heat experienced when driving at the limit. What's the worst condition for brakes? 3 H's. Hot, Heavy & High Speeds.
HOT... BBK's are much better with dealing with heat than an OEM caliper. A racing brake is cast out of light alloy in order to draw heat away from the pad. If the pads get to hot they off-gas and prevent pad contact with the rotor and you get a hard pedal with no brake force. The racing brake piston is usually stainless steel which is an efficient heat blocker to prevent heat soak through the piston into the fluid. If you boil the fluid you will get a soft pedal with no brake force. A titanium shim is often between the pad and the caliper to block heat from going into the picton. Racing brakes use a vented rotor disc to cool the rotor and keep it from overheating. Some companies designs are better than others.
Heavy& High speed... Got a full weight vehicle? Got a fat driving coach sitting next to you? Got a full tank of gas, full interior and a roll cage, twin turbo kit making 600whp? Driving on a track with a long straight and hitting 180mph in 100 degree temps? Wow..... this is the worst conditions for a brake to deal with. far past what an OEM setup with any race pad could possibly deal with.
When looking into an aftermarket BBK that you intend to use for it's intended purpose look for a reliable setup. Who's racing with them? Don't see them on the track? That means the company isn't interested in sponsoring a car and putting their product to the test, or a team tested them and they failed to deliver.
Getting a light weight brake setup will decrease unsprung mass or simply the weight that the damper has to deal with. Less weight that the damper has to deal with, and the better control it will have over the spring and ulitimately keep the tire in contact with the racing surface. Look for a 2 piece rotor. These have a center aluminum mounting flange and a seperate braking surface. Get the smallest caliper that will do the job you need it to do. Generally as you increase the number of pistons you increase the size of the caliper. Doesn't the number of pistons dictate how much stopping force you have? No not at all. The tire dictates how much braking capability you have.
The more pistons the less rigid a cliper is for a given size. After all your removing material and creating a hole in the casting for another piston. A rigid caliper will give better brake fee land response, and will be easier to modulate. A six piston caliper must be larger for structural rigidity than a 4 piston caliper. Don't be fooled into the Taiwan tuner companies making 8 and 12 piston brake kits. They are simply selling to an uniformed consumer. Generally a 4 or 6 piston setup for the front is all you need. The 6 piston will be a bigger caliper and allow a bigger pad for endurance racing but this comes with a weight penalty.
Monoblock calipers are the ultimate in rigidity and performance. The price for monoblock calipers are cost prohibitive unless you make you livelihood as a race driver and someone else is footing the bill. We won't go any deaper into these since no one here will be usuing them.
Look for a BBK that keeps the OEM front to rear brake bias. This is important. No matter how many pistons you have the total piston area can't change from EOM piston area this will change the bias disturbing the balance under braking.
Check what compounds are available if you use the brake on the street and the track then look for a caliper that has pads available for both. Don't buy a pad for both jobs. Buy a dedicated track and a seperate street pad.
Don't buy crossdrilled rotors for track use. They will crack. Buy slotted rotors to prevent pad glazing, but pads will wear faster. Use blanks for the cheapest cost and pad life.
Look for a company that can get you parts easilly and cheaply. Look for a company that you can get tech support on the phone when you need them and not an import company that can't tell you a thing.
I made the choice of going with Stoptech and that choice has worked out well for me.
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