Then please tell me which one would have been the best!
KH Discs vs 73+ Discs
- Thread starter MuuMuu101
- Start date
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Then please tell me which one would have been the best!
All good man. Unless I found a 65-66 I am good to go. Yeah not much of a crossbeeeder on this car. 65 is a different story. That's a 196456 model! With 73 demon brakes and rear end.
""They were replaced with a better, newer, more modern version. ""
A quote from your post , so the viper and most cars like it are going backwards with an inferior older design instead of the slider single piston marvel ?
abodyjoe
Well-Known Member
Was I talking about Viper calipers? No. Was I talking about 4 piston calipers in general? No. Reading is fundamental, comprehension is golden.
chryslerfat
Well-Known Member
I voted for the 4 piston KH as most performance cars come with multi-piston calipers. The KH was even used on the Mustang and if bolt pattern is the reason not to use it go with Mustang rotors.
No point in explaining RRR. Seems like folks are incapable of grasping that the better design in theory isn't always the best functioning part in practice.
Yes, the KH's are multi-piston fixed calipers, and in that respect are like a lot of modern performance brakes. Are KH's modern performance brakes? No, they are not. Yes, Vipers run multi-piston fixed calipers. They are not KH calipers.
Car and Driver did an interesting test in 1976, comparing the Dodge Dart Sport with a few other cars of the day.
Take a look at the braking numbers, which are from 70mph to 0. Now, guess which of the 4 cars uses a fixed,4 piston caliper...
That would be the L82 Corvette. And yes, it did stop shorter than the Dart sport, but here's the kicker, the L82 uses a 11.74" rotor. So, it should outperform the Dart by a lot, not just 6 feet. That additional rotor diameter is a big deal. Not only that, but those are 1.25" thick rotors too. I would absolutely bet that if you put the B/R body 11.75" rotors on that Dart, with the same single piston floating calipers, that it would out brake the L82.
Oh, and the Trans AM? With a 455? The one the weighed more and stopped 20 feet shorter than the L82? Yeah, it uses a single piston floating caliper and 11" rotor. Huh.
The graphic is from Allpar, http://www.allpar.com/cars/dodge/dart.html
You can read the original article from Car and Driver here [ame="http://media.caranddriver.com/files/chevy-corvette-vs-dodge-dart-pontiac-firebird-chevy-silverado-ford-mustang-archived-comparison-test-car-and-driverthe-fastest-american-car-chevrolet-corvette-comparo-april-1976.pdf"]http://media.caranddriver.com/files/chevy-corvette-vs-dodge-dart-pontiac-firebird-chevy-silverado-ford-mustang-archived-comparison-test-car-and-driverthe-fastest-american-car-chevrolet-corvette-comparo-april-1976.pdf[/ame]
Yes, the KH's are multi-piston fixed calipers, and in that respect are like a lot of modern performance brakes. Are KH's modern performance brakes? No, they are not. Yes, Vipers run multi-piston fixed calipers. They are not KH calipers.
Car and Driver did an interesting test in 1976, comparing the Dodge Dart Sport with a few other cars of the day.
Take a look at the braking numbers, which are from 70mph to 0. Now, guess which of the 4 cars uses a fixed,4 piston caliper...
That would be the L82 Corvette. And yes, it did stop shorter than the Dart sport, but here's the kicker, the L82 uses a 11.74" rotor. So, it should outperform the Dart by a lot, not just 6 feet. That additional rotor diameter is a big deal. Not only that, but those are 1.25" thick rotors too. I would absolutely bet that if you put the B/R body 11.75" rotors on that Dart, with the same single piston floating calipers, that it would out brake the L82.
Oh, and the Trans AM? With a 455? The one the weighed more and stopped 20 feet shorter than the L82? Yeah, it uses a single piston floating caliper and 11" rotor. Huh.
The graphic is from Allpar, http://www.allpar.com/cars/dodge/dart.html
You can read the original article from Car and Driver here [ame="http://media.caranddriver.com/files/chevy-corvette-vs-dodge-dart-pontiac-firebird-chevy-silverado-ford-mustang-archived-comparison-test-car-and-driverthe-fastest-american-car-chevrolet-corvette-comparo-april-1976.pdf"]http://media.caranddriver.com/files/chevy-corvette-vs-dodge-dart-pontiac-firebird-chevy-silverado-ford-mustang-archived-comparison-test-car-and-driverthe-fastest-american-car-chevrolet-corvette-comparo-april-1976.pdf[/ame]
LocuMob
Fluid Technician
I got all I needed for a swap to 73+ discs at the parts store except UCA's and the caliper brackets. I tried KH, but that was a no go and expensive, even with me working at the parts store. They just weren't worth pursuing. I got then11.75" rotors and pin type calipers. I'm not building a canyon carver, but it will stop with no problems. I went with 73+ because other than 2 items, it's easy to do the swap and the stopping power is awesome bang for the buck.
So let me get this straight. You're going to ignore the only actual data anyone has posted so far, and continue to post your opinion about a brake with which you have no actual experience?
Got it.
Despite the fact that the KH calipers have a smaller piston area? And a .75" thick rotor?
HemiMark
Well-Known Member
I vote KH. I don't like the wider track with the 73 & up setup
The master cylinder bore is an easy factor to change, much easier than the brakes themselves since in this case that usually requires different spindles. Matched properly it would be better to have the larger piston area. Same for rotor thickness- we're talking about the same car, so, vehicle weight is the same. The 1" thick rotors do experience fade in hard driving conditions, so, the .75" rotors would only be worse. So how does that make them better brakes?
I don't understand your thermodynamics statements at all. The sole function of brakes is to convert mechanical energy into thermal energy. That is what they do. While I understand you don't need thermodynamics to tell you how to calculate the clamping force of a set of calipers, you do need thermodynamics to tell you if your braking system will actually work in the real world. If you only possess a rudimentary understanding of thermodynamics, how do you go about designing a more efficient braking system? Brake fade, due to heat, is by far a more important factor than simple clamping force if we're talking about real world use. I would much rather have brakes that resisted fade and maintained their braking capabilities, but had slightly less clamping force, than a set of brakes the had amazing clamping force and were cooked (and therefore useless) after two corners.
And, I read the thread you linked. A thread where you talk about things you've already laid claim to here, namely your vast experience designing brakes. But then you also go and say things like you "struggle to understand" the concept of only using one side of the caliper to calculate piston area in calculations for fixed calipers. It isn't all that difficult of a concept and one I would think someone that has actually designed fixed caliper brakes would have a really good understanding of. Sorry, but that only leaves me even more confused as you what you do, or do not, know.
Sounds like a classic case of splittin hairs on our cars to me.
http://www.whyhighend.com/floating-vs-fixed-calipers.html
Keep this in mind. Nearly ALL of BMW's models have floating calipers. But nobody's ever raced a BMW before. <rolls eyes>
http://www.whyhighend.com/floating-vs-fixed-calipers.html
Keep this in mind. Nearly ALL of BMW's models have floating calipers. But nobody's ever raced a BMW before. <rolls eyes>
I'm not trying to pick a fight. You were the one that said you designed brakes. You're pushing your opinion on people that are actually trying to decide what brakes to use, to the extent that you told another member that he didn't make the best brake choice. Yet, you have provided no evidence to back this up. In post #5 you says "Rotor diameter and total caliper piston area are everything in brake torque." In post #72 you say "Smaller piston area means nothing by itself, adjust the mechanical leverage ratio and/or the m/c bore size to achieve the pedal feel desired. "
All I'm trying to do is make this clear for folks that are trying to pick a set of brakes.
This is simple, it's Newton's 3rd law. The single piston slider exerts just as much force on the backside of the rotor as the front. The formula doubles the area of the pad to reflect this for simplicity, because it's the same force as on the other side. The formula does take into account both sides, as long as you publish the formula properly, which you didn't. You left out multiplying the friction coefficient by 2. From Stoptech...
Tw= Ps x AP x µ x 2 x Re
Tw= Brake torque at the wheel
Ps = Pressure of system; AP = Total Area of pistons in one half of caliper (one side of opposed type or active (piston) side of sliding or floater type);
µ = Friction Coefficient; x 2, since there are two sides of the rotor that the pads are exerting force against;
Re = Effective Radius of clamping force.
The fixed caliper works exactly the same way, each bank of pistons is providing the same amount of force. That doesn't double the force, it applies the SAME force to BOTH pads. So, you only consider half of the caliper, but double the coefficient of friction.
Here's a better explanation of why that works like that
https://enderw88.wordpress.com/automotive-theory/brake-system-theory/
What, having a better service life is a bad thing? And yes, actually, having more fluid in the caliper to boil IS an advantage. It takes longer to heat up a larger volume of fluid. And, that larger volume of fluid will likely have a larger surface area with which to transfer heat back the environment. And if you scale the master cylinder to maintain the total system leverage, you haven't lost anything from a braking perspective, and might even have gained some improved fade resistance. Yes, that's definitely splitting hairs.
Right, your term was "basic", rudimentary is a synonym. Brake fade resistance also isn't the only advantage of a thicker rotor. And yes, there are other factors, but they generally favor thicker rotors, not thinner.
As far as being a "thermo genius", no it's not necessary. But considering that generating heat is what a brake does, and the ability to exchange that heat to the air determines how well your brakes will continue to work, I don't see why you wouldn't want to be, or have, a "thermo genius" on hand to improve your design. The more efficiently a set of brakes dissipates heat the better they will be.
Jay_340
Moparologist
Does the KH setup have the same track width as the 10" setup? I'm planning on keeping the small bolt pattern and would hope that the track width would not be altered too much.
That's not the case at all. I even learned a few things cross-checking some of your input.
My only point is that you shouldn't be throwing your opinion out there as fact. I have plenty of opinions that plenty of people here don't agree with.
Really? Because Newton's 3rd law of motion explains exactly what's going on with a single piston sliding brake. That's high school physics.
"The third law states that all forces between two objects exist in equal magnitude and opposite direction: if one object A exerts a force FA on a second object B, then B simultaneously exerts a force FB on A, and the two forces are equal and opposite: FA = −FB. The third law means that all forces are interactions between different bodies, and thus that there is no such thing as a unidirectional force or a force that acts on only one body"
https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion
ir3333
Well-Known Member
i.e. if you push a desk with 50lbs. of force and it doesn't move then the desk is pushing back with an equal 50lbs.
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