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I prefer multiple piston calipers over a single piston for one simple reason. I feel with a fixed caliper and pistons squeezing from both sides there is more likely to be equal pressure on both sides of the rotor rather than counting on a caliper that slides freely. Ive seen far too many sets of brake pads on daily drivers with one pad worn considerably more than the other. However, there is nothing wrong with a single piston setup as long as its serviced properly.
 

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We've measured a third shorter stopping distance and a greatly improved resistance to fade with our 13" system over stock Kelsey Hayes brakes:

 

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Shaun sorry but those original brakes must have had some glazed or grocery-getter pads in them for the cold stop to be so bad. Those brakes can do much better than 200 ft stops in a 3000lb Mustang.

to the OP, PBR calipers have small pistons. You have to watch your total piston area, since it’s critical to brake pedal effort. You can juggle master cylinder Bore size to make it up but you need To know what you’re doing. Wilwoods 6 piston area is actually less than several of their 4 piston ones, so watch out there too.
Go with a vendor that can talk you through this to help you get it right the first time. Two of them posted on this thread.
good luck!
 

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Shaun sorry but those original brakes must have had some glazed or grocery-getter pads in them for the cold stop to be so bad. Those brakes can do much better than 200 ft stops in a 3000lb Mustang.
The pads fitted to the original system were the standard pads that came with the SSBC K/H kit. Historically I have found them to not be very good. Certainly you can improve the stopping distance from just under 200' with better pads.

I would be happy to hear what results someone could achieve with the original brakes and better pads.

The test was mainly done to highlight the importance of increasing rotor diameter when using larger diameter wheels. Those small rotors give up a lot of mechanical leverage with 17" wheels.

The second part of the test shows how much better our system is at absorbing and shedding heat. The stock Kelsey Hayes fading out to 300' 60-0mph over 5 stops while our 13" system maintained 130' to 135'.
 

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The test was mainly done to highlight the importance of increasing rotor diameter when using larger diameter wheels. Those small rotors give up a lot of mechanical leverage with 17" wheels.
This piques my curiosity... regardless of whether you have a 14" wheel or an 18" wheel if the overall circumference of the tire is no different the rotor size would become insignificant, eh?
 

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This piques my curiosity... regardless of whether you have a 14" wheel or an 18" wheel if the overall circumference of the tire is no different the rotor size would become insignificant, eh?
True, the overall diameter should stay the same but typically larger wheels are heavier. More centrifugal force. Big heavy flywheel vs. small light flywheel...
 

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I upgraded my TBird front brakes from one piston to two piston calipers. It was an amazing improvement. These cars also had a "sport" option with one inch larger rotors and single piston calipers. Many people have said the smaller rotor with the two piston caliper is superior to the sport brakes whose main feature is just a larger rotor. It's possible the larger rotor may fade less when abused. The two piston caliper has better feel and modulation. I don't have any problem with fade driving reasonably with 11 inch rotors.
 

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Not caring how or why it occurred, one of the better mods on my 69 Mach was removing the 2001 Cobra 13 front brakes and installing 2014 Mustang GT 4 piston Brembos with 14.2" rotors.
 

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Discussion Starter #30
Not caring how or why it occurred, one of the better mods on my 69 Mach was removing the 2001 Cobra 13 front brakes and installing 2014 Mustang GT 4 piston Brembos with 14.2" rotors.
You must be runnin at least 18” wheels?


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I am running 18 inch. But my oem 2001 Cobra 17x8's bolted up just fine and rotated about 340° before they hit some interference.

Heck, F1 uses an 11" rotor on a 13" wheel. They may spend more than us though.
 

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Heck, F1 uses an 11" rotor on a 13" wheel. They may spend more than us though.
The ONLY reason they do that is the rules require it.

Larger rotors do give more braking power by virtue of their increase mechanical advantage. IIRC it's on the order of 5-10% per Inch increase, but I'd have to do the math. Without getting into the fine details like floating/fixed, stiffness, etc. caliper size (total piston area) is all about developing rotor clamping force in conjunction with a master that gives acceptable pedal travel. That's why trucks need power brakes/hydroboost, you can't develop enough brake pressure with just mechanical and hydraulic force multiplication without running out of pedal travel.
 
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