Brake System Calculations

[LevyB2]

I'm working on calculations for the braking system for this year's car and since the brake line for each set of calipers (one for the front and one for the rear) splits at some point, I initially divided the line pressure from the m/c by 2 to account for this. However, based on what I've read and Race-Tech Magazine's braking model, you do not divide this pressure in half. Can someone please explain this to me?

[js10coastr]

The pressure is the same everywhere in the line.

[Composites Guy]

Pull out your freshman physics book... look up Pacal's principle.

[Adam L]

This should help you... enjoy.

Calc (http://www.jakelatham.com/radical/info/brake_calculators.shtml)

[rjh23]

I was using Jake Latham's brake calculator, http://www.jakelatham.com/radical/info/brake_calculators.shtml.
I am unsure about two things. 1 When you enter the front piston diameter, do you enter the diameters for both front calipers? 2 What exactly is "Front Pad Radial Height"?

[Mike Sadie]

i believe the front pad radial height refers to where the pad is actually applying force. its the radial width of the pad. its kind of hard to explain.

[The AFX Master]

pressure will be equal everywhere on the front line, and in the everywhere on the rear line, But those pressures are different if you're using a bias bar connecting your master cylinders, be aware of that.
Doing some static calcs over the bias bar will give you the percent distribution of braking force (front/rear over 100%), and will aid you to tune your braking bias to match maximum braking force at a fixed weight transfer

[rjwoods77]

RJH23,

It is your best interest to write your own program so you understand what is going on. It is pretty easy to do. The head of engineering at Stoptech, Steve Ruiz, is also a brake design judge so you can be sure of the validity of these papers. One very important thing to understand comparing the physics vs mechanical stopping power of your car. You want to maximize the braking based on longitudal grip of the tire. Doing the weight transfer calc will show you how much load you will actually have on the front tires. I found the best way to quantify the braking system is in terms of pedal load. Compare your mechanical vs physics to the pedal load and it will show you what the tires are capable of and what you hydraulic system is capable of. You want the two to pretty much line up at similar pedal force. Actually a little more mechanical pedal force so you know you can lock them up under max conditions since the other way will cause the driver and car more problems. If you dont know these equations in and out along with their effects then you will get smashed at design.

http://www.stoptech.com/tech_info/tech_white_papers.shtml

http://www.stoptech.com/tech_info/The%20Physics%20of%20Braking%20Systems.pdf

[ahmed]

Originally posted by LevyB2:
I'm working on calculations for the braking system for this year's car and since the brake line for each set of calipers (one for the front and one for the rear) splits at some point, I initially divided the line pressure from the m/c by 2 to account for this. However, based on what I've read and Race-Tech Magazine's braking model, you do not divide this pressure in half. Can someone please explain this to me?

[alumasteel]

http://fsae.com/groupee_common/emoticons/icon_confused.gif

Is this a random bump of a thread that should have never been started? Or has the laziness on this forum really deteriorated to the point that people aren't even asking their own questions?

[Wolf]

Originally posted by rjwoods77:
RJH23,


http://www.stoptech.com/tech_i...h_white_papers.shtml (http://www.stoptech.com/tech_info/tech_white_papers.shtml)

http://www.stoptech.com/tech_i...raking%20Systems.pdf (http://www.stoptech.com/tech_info/The%20Physics%20of%20Braking%20Systems.pdf)


I know this is an old thread but here goes maybe someone could shed some light on my confusion:

based on the info I found in the links above, it is explained that the pressure generated by the master cylinder is equal to the BrakePedal force devided by the effective area of the M.C piston. shouldn't this be the brake pedal force multiplied by the pedal ratio devided by the piston area??
thanx

[Mikey Antonakakis]

Originally posted by Wolf:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rjwoods77:
RJH23,


http://www.stoptech.com/tech_i...h_white_papers.shtml (http://www.stoptech.com/tech_info/tech_white_papers.shtml)

http://www.stoptech.com/tech_i...raking%20Systems.pdf (http://www.stoptech.com/tech_info/The%20Physics%20of%20Braking%20Systems.pdf)


I know this is an old thread but here goes maybe someone could shed some light on my confusion:

based on the info I found in the links above, it is explained that the pressure generated by the master cylinder is equal to the BrakePedal force devided by the effective area of the M.C piston. shouldn't this be the brake pedal force multiplied by the pedal ratio devided by the piston area??
thanx </div></BLOCKQUOTE>
That would be correct.

[Mikey Antonakakis]

Originally posted by Wolf:
I know this is an old thread but here goes maybe someone could shed some light on my confusion:

based on the info I found in the links above, it is explained that the pressure generated by the master cylinder is equal to the BrakePedal force devided by the effective area of the M.C piston. shouldn't this be the brake pedal force multiplied by the pedal ratio devided by the piston area??
thanx
That would be correct.

[MUsusp72]

Just to clarify I believe that the reason for the confusion is because they used the brake lever ratio in their formula to find the Force from the brake pedal. They just expanded it into 2 formulas instead of using one.

[Storm]

don't u think the line pressures calculated in step 3 is wrong?
Originally posted by Adam L:
This should help you... enjoy.

Calc (http://www.jakelatham.com/radical/info/brake_calculators.shtml)