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Originally Posted by stownsen914
I have Wilwood Superlites on my racecar. They are fine calipers, but as noted, plan to rebuild them more frequently due to lack of dust seals on the pistons.
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Quote:
Originally Posted by stownsen914
My dad put the same calipers on the front of a '70 911 track car years ago with Carrera rotors, and they worked pretty well. If you get the piston sizes right in the Wilwoods (there are a few options), you can keep the brake bias where it needs to be too. He kept the stock rear calipers (it was a 911S), and bias was OK.
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There's a big part of the issue right there, brake balance is key. The only problem w/ stock brakes is
thermal issues on heavier and faster cars. Stock brake torque bias is just about perfect for sporting use on a stockish car. Suspension setup, wheel/tire and aero all complicate this. If you want to address the thermal issue, use better cooling, better fluid, better pads, better technique, lose weight. If changing hardware the front rotors are the parts that need to be enlarged, rears only for balance, then use what ever calipers work w/ the rotors and wheels.
Keep in mind that it's the tires that are the primary factor in how fast the car stops, the latest Performance Friction calipers and rotors from a Cup car won't make your car stop any faster than stock A/M's unless the tires are upgraded.
Quote:
Originally Posted by stownsen914
Also, consider upgrading the master cylinder to a larger one. Wilwoods are 4 piston calipers, so there is more brake fluid displaced when you step on the pedal. I recall that on my parents' car the brake pedal was softer with the Wilwoods. I forget now, but I seem to recall that there was a 23mm Mercedes one that people used to use. Not sure what the options are these days.
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Just because there are more pistons it doesn't mean the m/c needs to be changed, The driving factor here is the slave/master ratio. You want to keep the slave/master ratio in the range of ~40 to ~30, The lower the better for sporting use. The lower limit is what's physically comfortable for the driver to use for his longest stint, the high end limit(~45) is the rate of volume flow of fluid in a panic stop. Street cars tend to be at the higher end because the manufacturers have to provide for just about anyone to be able to drive no matter how frail.
At the higher end the pedal gets soft and spongy it requires less effort to generate the same brake torque. At the lower end the pedal is high and hard, perfect for better modulation.
Power brakes further complicate the issue, they will be better on cars w/ lower S/M ratios than on those w/ high ratios.