Brake performance

Well when it dries up here Ill try again in daylight, maybe set up some markers. But honestly it seemed like less than car length, not by much but still. Even my passenger agreed.
 
crash said:
Plus that equation calculates the shortest theoretical stopping distance, not the actual stopping distance. Actual stopping distance calculations would factor in the weight of the car.
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Nope.

As stated before, mass is indeed in the formula setup, but cancels itself out (f(x)*m/f(y)*m...m's cancel) in the friction (u) constant.
 
logres said:
Nope.

As stated before, mass is indeed in the formula setup, but cancels itself out (f(x)*m/f(y)*m...m's cancel) in the friction (u) constant.
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This assumes that the limiting factor in stopping the car is the traction between the tires and the road. This is normally the case, but when your brakes cannot produce enough clamping force to overcome additional weight in the car, the stopping distance will be greater. Just like when I'm carrying 2000 pounds in the back of my 95 F150. It takes longer to stop, not because of the tires, it's because the brakes suck.
 
crash said:
... Just like when I'm carrying 2000 pounds in the back of my 95 F150. It takes longer to stop, not because of the tires, it's because the brakes suck.
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...as do most of Ford's light-duty pickups. :p

The Super-Dutys always seemed to have better brakes but still not much to brag about.
 
crash said:
This assumes that the limiting factor in stopping the car is the traction between the tires and the road. This is normally the case, but when your brakes cannot produce enough clamping force to overcome additional weight in the car, the stopping distance will be greater. Just like when I'm carrying 2000 pounds in the back of my 95 F150. It takes longer to stop, not because of the tires, it's because the brakes suck.
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True, if the 'u' constant only took into account friction of the tires and the road. The intent of 'u' in the formula is the overall 'friction' of the system - tires to road, pads to the rotors, etc...anything that causes deceleration.
 
That's just it, the friction coefficient is not constant between the pads and the rotor. 1/2 m v^2 is the energy needed to stop a vehicle. This energy gets transferred into heat by the brakes. More mass, more heat in the brakes. The coeff of friction between the pads and rotor goes down with increased temperature (with street brake pads), therefore reducing braking force, increasing braking distance. This is our friend, brake fade.
 
crash said:
That's just it, the friction coefficient is not constant between the pads and the rotor. 1/2 m v^2 is the energy needed to stop a vehicle. This energy gets transferred into heat by the brakes. More mass, more heat in the brakes. The coeff of friction between the pads and rotor goes down with increased temperature (with street brake pads), therefore reducing braking force, increasing braking distance. This is our friend, brake fade.
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I'd assume the coefficient is the average 'u' over the entire time of braking.

Is it reality? No, but it is within 10%.

And if one were to spend a little more money on good pads (like Greenstuff), there's no such thing as brake fade. The rotors will glow orange before the pads give up any friction.
 
Who are you asking? This thread is kinda old, although you posted on here as well.
 
logres said:
That won't be a problem.

But I almost forgot. What kind of rotors are you using? The Greenstuff runs really hot, and I warped my former $20 Autozone specials within 2 weeks. The frozen rotors I replaced them with have withstood the heat though.
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Logres
 
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Hasn't he ?

I know.its old, I started it.

Oh well, can anyone recommend a good frozen rotor ?
 
Thanks DLF, have you actually used these? Would the regular frozen slotted ones suffice?
Looks like there are three levels of rotors.
 
calisonic said:
Thanks DLF, have you actually used these? Would the regular frozen slotted ones suffice?
Looks like there are three levels of rotors.
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I'm not currently using their rotors, but in the past I've had them "freeze" some Brembo rotors for my Cobra, and I was pleased with the results.

As for the choices, "you pays your money and takes your chances".

I prefer drilled/slotted rotors with my Brembo's, but I'd probably recommend the slotted rotors on a Mark VIII with stock calipers.
 
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Sounds good.
I'm also talking to bill at scp about then possibly being defective as they have warped in about four months after being turned. He says these kvrs pretty much don't warp.
 
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Bill at scp is willing to sell me some of the same kvr rotors at a discount because they are out of warranty, which id like to to if I knew they would not warp again. However, kvr won't warranty these if I use my existing ebc greenstuffs. They sat any inconsistancies in the pads would translate to the rotors, which makes sense.



I really don't want to throw away these ebc's though, they only have about 20k miles on them and stop great.



Kvr also said that the ebc's are a very "hard" pad and don't grip real well but last long. I don't really agree w that.
 
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I used to have KVR rotors befor the Cobra swap and found them to be good but mine was not a daily driver.
 
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