Big brake kit from VAS

[coise]

VX means volumex and it´s a spider equipped with a compressor.
Yes, I agree it is expensive . Althought the website is in English...
You could also adapt an other MC I think I´ve seen posting in the forum about that. Don´t ask me where...

[vandor]

Coise, please explain why a different master cylinder would improve braking performance.

[ORFORD2004]

http://www.ebay.com/itm/Fiat-124-Spider ... 485bb032c9

[cormac]

Coise, please explain why a different master cylinder would improve braking performance.

Csaba

call me crazy but methinks your question was either rhetorical or a quagmire of gigantic proportions , or a teaching exercise , play nice

[coise]

Well ,
Vandor to my understanding the volumex was a lot more powerful car and therefore Fiat added a better braking system. I don´t know the size of the MC or the rotors but I´m pretty sure they were bigger.
That´s my 2 cents of logic.

Maybe, you could ask your friend Guy croft he knows more about the volumex then me for sure. I´m just an idiot trying to help.

[4uall]

I found some info to possibly support that

http://archive.mirafiori.com/show.php?fid=3&msg=5257

[FiatMac]

If you can lock up the brakes, then your brakes are as effective as they can get.

[quote="coise"
You could also adapt an other MC I think I´ve seen posting in the forum about that. ...[/quote]

If you are looking for lower braking effort then a master cylinder with a smaller piston will increase caliper clamping force for the same pedal force. However, this would result in more pedal travel. I am not sure what pedal travel you have with these Wilwood calipers(it depends upon what piston area they have compared to the stock caliper) but the system with the stock calipers already has too much pedal travel in my opinion.

[coise]

Yes, you are right Fiatmac the pedal travel is long, and just as much as with the stock brakes.

But the braking with the willwood is much better since the rotors are bigger and don´t overheat (going down the mountain for exemple) because they are vented.
Anyway, I like it the way it is on my car, it fits my driving.

[BEEK]

Hydraulic System
An important hydraulic principle states that fluids do not compress or produce any measurable friction.
Also, fluid pressure does not diminish when transferred within a closed system. That means that if there
is no leak in a system, the pressure at the wheels will be the same as the pressure from the master
cylinder.

A second hydraulic principle states that a relationship exists between:
• Force and piston area
• Piston travel and piston area

From the first principle, if a master cylinder generates 500 psi, it also transfers 500 psi to the pistons in
each wheel cylinder (remember that fluid pressure remains constant).

In the second principle, when pressure from a one-square-inch master cylinder piston exerts 500
psi on a wheel cylinder piston, which also has one-square-inch surface area, the wheel cylinder piston
transfers 500 pounds of force to the brake shoe (500 psi x 1 in. sq. = 500 lbs.)
However, if the same one-square-inch master cylinder piston exerts 500 psi on a wheel cylinder piston
that has a two-square-inch area, the wheel cylinder piston will transfer 1,000 pounds of force to the
brake lining (500 psi x 2 in. sq. = 1 ,000 lbs.)

Additionally, different piston sizes not only affect the amount of brake force applied, they also determine
the travel distance of the different pistons. For instance, if the one-square-inch master cylinder piston
moves one inch, a one-square-inch wheel cylinder piston will also move one inch (with the same force).

If that same one-square-inch master cylinder piston moves one inch, then a two-square-inch wheel
cylinder piston (twice the size) will move just one-half inch (half the distance) but with twice the force

[cormac]

Csaba, wow...look at what your post/question has prompted...cool, a discussion attempting to bring in some science

folks, these links are not real exciting, but some good (arguable to a point) information and education present, but no idea if beneficial, is needed, or helpful for what any of us are doing, but for the voracious readers and those interested I will put the links in...trust me I have not read all or ever intend to

here is a paper that includes Beeks information (pg 3)

http://teachersites.schoolworld.com/web ... brakes.pdf

and a more recent comprehensive paper

http://144.162.92.233/faculty/djones/to ... brakes.pdf

here is a page from StopTech (Centric Parts) with some white papers that are a little more specific, easier to read and some real world application

http://www.stoptech.com/technical-suppo ... ite-papers

and finally a page with a really nice (IMHO) tech article about brakes from of all people a 4x4 rock climber named Bill Ansell - actually he writes some very interesting and informative tech article on other subjects as well

Hey guys...sorry about all the links and information...just some stuff/resources I had acquired trying to become informed and help me muddle through the mechanical dogma

[coise]

Cool, this is good information.
Thanks Cormac and beek

[vandor]

call me crazy but methinks your question was either rhetorical or a quagmire of gigantic proportions , or a teaching exercise , play nice [/quote]

[timinator]

Hydraulic System
If that same one-square-inch master cylinder piston moves one inch, then a two-square-inch wheel
cylinder piston (twice the size) will move just one-half inch (half the distance) but with twice the force

Actually, there are two calipers so the pedal moves 4 times as far. It can be a problem.
I have enjoyed the experience of dealing with 13" tires on a fast, light weight autocross car. With all the upgrades(?) that have been discussed so far it made for brakes that locked up easily and and had no sense of feel to them. I call it modulation. Going into a fast corner it was difficult to tell what was enough braking, or when the brakes would lockup.
Putting 15" tires and larger rotors, while using the original calipers, on the car made an incredible difference in braking. Stopping distance and brake modulation became so much better as to be almost indescribable. As an added benefit the selection of good tires in 15" is endlless as opposed to the two or three in 13". Putting a big brake kit on a car with 13" tires is an upgrade in name only IMHO.

[FiatMac]

This discussion is around the original Wilwood caliper big brake kit offered by VAS. They recently came out with an economy big brake kit using a commercial sliding pin caliper and vented rotor. Anybody out there who has installed this one?