G_Body_Enthusiast said:
im thinking no such thing.
You clearly stated you thought that the vette calipers have more volume because they're twin piston instead of single.
Refer to the quote in my post above where you say so, in plain terms.
G_Body_Enthusiast said:
what i am thinking is that if i had a larger bore master then it would push more regardless of the caliper being used BUT IF the caliper had larger volume the caliper would work about as well as it would if was put with the master designed for it. now if the c5 caliper is smaller in area, then it probably has less volume behind those pistons so lets go with that. that makes it easier to fill with a larger amount to push into it, 1 1/8" vs 1" for the c5. less pedal effort is the result.
Yes, you should pair a larger master with larger volume calipers, so why are you going backwards?
You've got it twisted again...
A larger bore master will produce MORE VOLUME, assuming the same pedal ratio/pedal stroke.
A larger bore master will produce LESS PRESSURE, assuming the same pedal ratio/force applied.
This means MORE pedal effort for the same amount of line pressure (due to the increased volume output of the master), not less pedal effort.
Less pedal STROKE. More EFFORT.
G_Body_Enthusiast said:
the dual pistons do distribute the force more evenly and is a large part of the reason why i want to upgrade to them. that also means it can handle more force, so a slightly bigger bore can be tolerated. the c5 calipers use a 1" bore master, the
b-body is 1 1/8". now i dont know the actual travel of the pistons in the cylinders but i'll guessing the
b-body has longer travel than the vettes given i've driven both cars before. the vette has touchy brakes, they GRAB, not pull you to a stop like these stock ones do now. i'll take a guess and say it's because more force is being put on the rotor due to a combination of factors.
No.
A SMALLER bore could POSSIBLY be tolerated since you don't have to push as much volume into the small calipers, and a smaller bore master will produce more pressure. More pressure = more force (all else being equal). And 1/8" difference in bore makes a large difference. Try 1/16ths for slight changes.
1" diameter = 0.785 sq in
1-1/8" diameter = 0.994 sq in
Suddenly 1/8th of an inch diameter makes more than a 1/5th of an inch^2 in area (which is the measurement that counts).
For those who are counting, that's an increase in master cylinder area of 26%!
I'm not a pro on vette braking systems, but I would bet the vette stops quicker than the
B-body largely because it weighs a whole lot less. And just guessing, but I bet the vette had softer compound tires on it, thereby allowing more braking force without lockup. (Or the start of lockup, because of ABS, in the case of the vette).
And yes, caliper stiffness, pad coefficient of friction, loaded tire diameter to rotor diameter ratio, caliper piston area to master cylinder area ratio, booster force all play a part. And I bet most of those factors are in favor of the vette too.
G_Body_Enthusiast said:
the bore for the primary on the g-body master is under an inch, the C5 master is 1", so right off the bat there is less volume at the top to push with. the
b-body is being chosen since it's bore is 1 1/8" so it may reduce pedal effort.
i think pad size as well as material is important. the vette pads have a larger contact area on the rotor i believe. that can make a difference in braking too and something i considered. im also thinking ceramic since if it's good enough for a vette, it's good enough for my car. i know ceramic brakes have a more aggressive bite to them, wears rotors out a little faster too.
now i'm not a showy person with my car BUT it would be nice that while i am getting larger wheels anyway, i think it would look silly to have the stock brakes on there. 17" wheels and a bunch of space where bigger brakes could be doing what brakes do, stopping my car look rather stupid. just so i can look and see nice big rotors and know the car stops a lot easier. i really dislike how poorly my brakes perform.
while i believe the stock master would work fine, i believe a
b-body master (regardless of the booster i use) would perform better. my thinking behind this is if i'm going well beyond factory brakes i might as well go all the way and tweak the brakes as much possible to get better performance out of them. that and i think it's important to remember the volume in the piston(s) and the master cylinder and hard line sizes to replicate the same setup on your car as the "donor car" as best you can. the
b-body has a larger bore and while i think that may be a bit much for vette calipers given they're designed for a smaller bore master, i do know it was a popular mod some time ago to at least get better performance from stock brakes with a
b-body master and booster. now try doing it with a caliper that has less area for the "piston". it responds faster to the master but not if the bore is smaller than the one designed for the calipers (like the stock g-body master, less than 1"). basically it wont work as well as designed to. why buy vette brakes only to have less than vette performance from them? the amount may even be minimal and it probably is but i want the most from my brakes, i'm paying for them after all. i think those 1/16"s and 1/8"s add up enough and make a difference. lesser or greater according to your eye for detail.
An 1-1/8 bore master cylinder will INCREASE pedal effort compared to a 1"... no probablys, maybes or supposes. It will, however, reduce pedal STROKE. You're confusing volume and pressure. Volume gives you quantity of movement, pressure gives you force.
Why bother replicating the donor car when the car they're going into isn't the donor car? Use it as a starting point I suppose... but a vette isn't a
b-body isn't a g-body.
You can't replicate the low weight and weight distribution of a 'vette. Use the vette components where you need, but all the tuning is out the window. You should replicate the g-body setup, and note what changes the the C5 components make and compensate for them. If you come out with the same theoretical caliper force, you'll have the same pedal strokes (assuming you use the same master and pedal ratio), but if you combine that with a larger rotor and more aggressive pads, you'll gain overall braking force, and you'll have more thermal capacity (due to rotor size). If the calipers are stiffer, it'll essentially be more efficient too.
The ONLY force you have to work with, is the force of your foot, amplified by the pedal ratio, plus the booster force, amplified by the caliper area to master area ratio, amplified by the rotor/tire diameter ratio. Use a stronger booster or larger rotors, and you should increase your braking force without changing much else. (With the rotors, this should be true as long as your tire diameter stays the same).
I would highly recommend doing some reading on braking systems before diving into this.
EDIT:
Check this out:
www.sae.org/students/presentations/brakes.ppt
I'd also look into basic hydraulic stuff... Here's a good starter on brakes, which includes some hydraulic information. I haven't read it word by word, but it looks good.
http://www.autoshop101.com/forms/brake01.pdf
I would also recommend checking out the stoptech website. Start off with their FAQs
http://www.stoptech.com/tech_info/faqs.shtml
(some of these are directly related to stoptech parts, but many are general in nature)
Then some white papers. Don't dive right in, start with the more basic stuff first, like the glossary and "Understanding braking experiences".
http://www.stoptech.com/tech_info/tech_ ... pers.shtml
