Anyone installed them yet? any experience?

 

 

I have my own version that works well, but I have C5 rears as well. If you use the VBP kit in the front only, I would make sure you have an adjustable proportioning valve to dial in front to rear bias.

There was one guy on here who installed the VB kit and had rear lockup issues at first where the rear would lock before the fronts. He worked it out, but I don't know what he did.

Check out my site below for more info on my C5 brake swap.

 

I have them and they work great, had to do some grinding on the brackets ,
Vpb may have the kit corrected by now as in instructions on how it bolts up.
I have manual brakes, and the stockers sucked big time,as for the backs locking up, I haven't had a problem with them but yes ,if I do stomp on the brakes really hard the back does (kinda ) lock up first, but isn't bad, The stock brakes were more dangerous !
These are a BIG improvement.

 

You might want to do something about that. You don't ever want to rears to lock up first.

 

Some really wide tires on the back may cure that!

 

Actually I think that it would be just the opposite because of the loading per square inch.

 

That is a common misconception. On pavement, the more tire on the ground the more traction you have. It is a function of unit area and how the tire grips the surface (chemical bonds) that outweighs tire loading. That's not to say that tire loading is irrelevant. It just isn't as large of a factor as surface area is when comparing overall traction.

 

Can somebody explain the reason for rear tires locking if using stronger front brakes? A stupid would assume that stronger brages in front make the front lock first. but the logic here must be maybe the pressure inside the barke lines or area of pistons or what it is...

 

The front of the car does anywhere from 70-90% of the braking. Thats why the fronts are always bigger than the rear. And it is how the manufacturer sets up the brake biasing.
Which end of the car locks first is all about brake biasing. And it has to do with a number of factors from calipre piston size, pad selection, rotor size, tire coefficient of friction and dynamic weight distribution. Suspension stoffness also has a part to do with it.

Basically when you slow down you car, the weight shifts to the front of the car and can be felt with the diving that the car does. With more weight on the front, the coefficient of friction for the front tires goes up so you can use more clamping force on the rotor without lockup. The coefficient goes down in the rear so you have to use less.


The term brake bias is used to describe which end of the car has more braking ability. If the front locks up first, then you have a front biased car and vice versa. You can adjust the brake bias a couple of different ways. Easiest for the consumer is to add an adjustable proportioning valve. This limits the rear line pressure, reducing the clamping force in the rear.

A better way of adjusting the bias is with caliper and rotor selection and to certan extent pad selection. Larger rotors or larger caliper pistons will shift the bias to that end of the car.

Another common misconception is that 4 piston calipers have more clamping force than 2. For the same size pistons, a floating 2 piston will clamp just the same as a fixed 4 piston.

Which brings us back to C5 brakes. The C5 calipers use a floating 2 piston design whereas the C3 uses the fixed 4. Also of note is the pistons in the C5 are much smaller than the C3 requiring a higher line pressure for the same braking ability. Some of this is compensated for with pad materials, pad swept area, etc. But the overall effect of adding C5 brakes to the front of the car only is a reduction in braking ability of the front which shifts the bias to the rear. Without adding the adjustable proportioning valve or some more aggressive pads for the front, then you will lock up the rears first like vetteaddic is experiencing.

 

Quote: Another common misconception is that 4 piston calipers have more clamping force than 2. For the same size pistons, a floating 2 piston will clamp just the same as a fixed 4 piston.
Just to set the record straight: a CAST IRON 4 piston caliper has FAR MORE clamping force than a Aluminum floating caliper AND! it will withstand way higher brake tempratures. I won't even get into the differences in brake pad suface area between the 2 designs, I will say that the C5 brakes WILL look better at the car show, their one advantage over the early brake system.

 

So using C6 Z06 6 piston calipers with 13" rotors should maybe come closer the balance than the VBP C5 kit ?

Lets wait which manufacturer comes out with a C6 brake kit first

Or then an adjustable proportioning valve like this with VBP kit:
http://www.zip-products.com/Zip/prod...C34CBB4C14AF19

 

They do look better and perform better than stock.
I drive my car hard and really haven't felt the rears lock up,
I only stomped on the brakes really hard to see if it would lock the rears once,but seems to not after warming the brakes a bit.


All this chit chat is making me go out and get the beast out.

 

good, vetteaddic, go drive that beast.

 

Are yourr wheels AR TT2 17X8 with 4"BS like mine? And no clearance problems at all?

 

This isn't quite right...

When the weight shifts the normal force on the front and rear changes (say instead of 50/50 it shifts to 70/30). The coefficient of friction is a function of the chemical makeup (and the surface that its touching...) and has nothing to do with the weight distribusion.

*shrug*

 

Yes AR T2s ,18x8 4.75bs and 18x10 5.75bs should have used 5.5bs on the back,had to use .25 spacer.

 

Ooo, brakes, one of my favorite topics!

First of all C5 brakes are not 'stronger' then the stock brakes. They may feel better than the unmaintained brakes you had but they are NOT a better caliper ( better meaning stopping the car better)

They actually supply less stopping power that the stock with the same MC.

If you had stonger brakes in front the front's would lock up first.

Not quite right either ;-)
The more load a tire has the lower the coefficient of friction it has. That is one reason why lightening your car make it's handle better.
The friction does of course rise (Coef * force = friction)


Nope. assuming the same piston area they will be the same. There's no magic in cast iron.

The aluminum caliper will disapate heat better than cast iron.

The best solution is a big aluminum 4 piston caliper. Thats why they use them on race cars.
Single or twin piston floating calipers are good for street cars because they have fewer moving parts and seals and are cheaper to make. They are NOT a performance caliper.

Thats why the C5 guys switch to Wilwood brakes when they get serious

Keith