Big Brakes on a not-so-big Budget? YEP

1Marauder said:
It makes sense to change the back pads when reconfiguring the front, right?

Looking to STOP, low dust, and a reasonable life (10M miles is unacceptable!).
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Absolutely it makes sense.

Any brake pad you choose will stop the vehicle, I promise. Lifespan will be similar enough between different brands and formulas that it need not be considered when replacing your pads - brake life has much more to do with how you use them.

I always use Centric Posi-Quiet ceramic's on my daily drivers. Always a quality pad, affordable, and very low dust and noise. They do produce a softer lower pedal that can take some getting used to, but if you throw your foot down that car will come slamming to a stop - no worries there. The lower pedal feel will give you excellent control of exactly how much brakes you apply at the lower level. These pads are a little more sensitive to getting beat on extendedly - I imagine I would fry them at the track pretty quick. I would highly suggest these pads.
 
Logizyme said:
I did not want to bring co-eff into the mix here because that has more to do with pad formula and heat. Pad formula being a choice to the user and heat being covered under fade topics.

I understand that in gereral pad size does not increase brake friction but it can if the pad sweeps a larger area of the rotor.

Assuming all other factors the same: If I have a pad that is 2" wide and 6" long, 12sq inches. Using a 14inch rotor, sweeping the area between 12" inside diameter and 14" outside diameter resulting in 40.9sq in of rotor swept area.

12 x 40.9 = 490.8 friction area per rev

If I have a pad that is 3" wide and 4" long, also 12 sq inches which means the the pad will have the same PSI, but now it sweeps a 3inch wide section of the rotor, 11" inside diameter and 14" outside diameter, resulting in a swept area of 59.0sq in.

12 x 59.0 = 708.0 friction area per rev

Friction has increased 60%, resulting in 60% greater stopping power and 60% more heat, which also means reduced pad life and quicker onset of fade.

Increasing the pads sq in will reduce the PSI but overall braking force will remain greatly unchange because of greater friction area but reduced pressure, but it will increase life expectancy and heat/fade resistance.

Honestly I think this tech discussion has gotten a little out of hand, and I know I'm not helping that :D.

Braking ability has much more to do with the grip of the tire, and even the stock braking system should be able to activate ABS with stock tires on dry pavement. I could activate ABS with my stickier nittos and stock brakes. So really the only way to improve our braking ability is with fade resistance - which has been accomplished with this system.
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I like the tech, agreeing or not. I'm good. Some further thoughts.

The only issue I take with this (agree that Cf should be evaluated as a constant and that tires play a huge roll) is that portion highlighted. Frictional force is not increased by 60% here. (forget the amount let's focus on if there is or not for simplicity) It's the same force over a longer (revolution) working surface. Great swept are IS a general indicator of greater efficiency I'll go there easily. You can swap a 12" rotor for a 14" and using the same caliper/pad get a huge change in torque- and efficiency by way of more swept area. Adding a larger pad won't multiply that tho.

The frictional area is increased perhaps but the forces upon the pad are the same total. And the forces upon the rotor are at a lower psi over the surface of the pad itself. Frictional force being defined by pressure (piston area) x the Cf of the material. The total surface area of the pad won't have a significant effect here. Spreading that same force over a greater surface

I've had this discussion over and over before and link to nearly every brake manufacture who covers such things- we're all on the same page. Often folks try to take net frictional work being done and back that into the equation of what it's producing. Kind of working the results into the formula. In this case frictional force is the result not a factor in what it does.



* I like to add this experiment: Stand on the bathroom scale. You weight 200lbs. You have a Cf of '0' at this point. Now lift one leg. Your're surface area has halved. You weigh 200lbs and you still have a Cf of zero. Now do that leaning over until you slip and fall off. Try it both ways- two legs then one. It takes the same effort to move that scale and fall on your butt. You get the idea. Now call a medic.
 
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Todd TCE said:
I like the tech, agreeing or not. I'm good. Some further thoughts.

The only issue I take with this (agree that Cf should be evaluated as a constant and that tires play a huge roll) is that portion highlighted. Frictional force is not increased by 60% here. (forget the amount let's focus on if there is or not for simplicity) It's the same force over a longer (revolution) working surface. Great swept are IS a general indicator of greater efficiency I'll go there easily. You can swap a 12" rotor for a 14" and using the same caliper/pad get a huge change in torque- and efficiency by way of more swept area. Adding a larger pad won't multiply that tho.

The frictional area is increased perhaps but the forces upon the pad are the same total. And the forces upon the rotor are at a lower psi over the surface of the pad itself. Frictional force being defined by pressure (piston area) x the Cf of the material. The total surface area of the pad won't have a significant effect here. Spreading that same force over a greater surface

I've had this discussion over and over before and link to nearly every brake manufacture who covers such things- we're all on the same page. Often folks try to take net frictional work being done and back that into the equation of what it's producing. Kind of working the results into the formula. In this case frictional force is the result not a factor in what it does.



* I like to add this experiment: Stand on the bathroom scale. You weight 200lbs. You have a Cf of '0' at this point. Now lift one leg. Your're surface area has halved. You weigh 200lbs and you still have a Cf of zero. Now do that leaning over until you slip and fall off. Try it both ways- two legs then one. It takes the same effort to move that scale and fall on your butt. You get the idea. Now call a medic.
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I'm going to go with the guy who makes and sells brakes :beer:
 
even though this discussion is all very informative, and above my head, there still seems to be good results. some tinkering may stil be needed. But isnt that what hot rodding is all about? trial and error? beside it looks good.
 
Guys...relax. I'm not asking anyone to take sides here. I've made mistakes and learned and still do. Read, enjoy, think and draw conclusions.

The root of this discussion (and it's a good one) is that what we are after is Brake Power (hate that term). It's actually brake torque. Or more specifically Rotor Torque.

In calculating rotor torque there is no use of or reference to pad square inches or swept area. Both of those are either a byproduct or not part of the formula. My point was that greater swept area (while good) does not act as a torque multiplier. If it were that simple you can be certain someone would wildly market "Oversized Power Pads" or such things that would be just a larger pad for the same caliper. *Yeah, you know someone would huh?!
 
even though this discussion is all very informative, and above my head, there still seems to be good results. some tinkering may stil be needed. But isnt that what hot rodding is all about? trial and error? beside it looks good.
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BIIIIIG Brake plus one to that!
 
HeavyMetalMerc said:
even though this discussion is all very informative, and above my head, there still seems to be good results. some tinkering may stil be needed. But isnt that what hot rodding is all about? trial and error? beside it looks good.
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What the hell I'll quote for truth too and make this a third post in a row
 
Todd TCE said:
The root of this discussion (and it's a good one) is that what we are after is Brake Power (hate that term). It's actually brake torque. Or more specifically Rotor Torque.

In calculating rotor torque there is no use of or reference to pad square inches or swept area. Both of those are either a byproduct or not part of the formula. My point was that greater swept area (while good) does not act as a torque multiplier. If it were that simple you can be certain someone would wildly market "Oversized Power Pads" or such things that would be just a larger pad for the same caliper. *Yeah, you know someone would huh?!
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I think most of us understand the laws of physics, myself including. No, brake pad area does not increase brake torque, to the first order. These same laws of physics specify that a larger tire does not provide more traction. Again, to a first order approximation. F=u*N. No area in this formula.

But let's not forget we're operating in the real world here with real friction materials that have temperature limits, wear rates, and detrimental behaviors like transferring hot pad material to the rotor, which causes pulsing and greatly reduces brake torque.

A good braking system will not only generate lots of brake torque, but will do so consistently over time, not get the pads hot enough to transfer material to the rotors under most operating conditions, and last at least 20K miles. This requires that the energy per square inch of pad area is not so high is to push it out of temperature range and cause accelerated wear. But this is the problem I have seen over and over again with the FNSL6R calipers on 14" rotors. I have NEVER claimed brake torque was in issue, at least as long as the rotors are still smooth. My car stops extremely well. For a few thousand miles. Then wear issues rear their ugly head.

We need larger pads and calipers so the large amount of energy (heat) absorbed by stopping a 4200 lb car is not concentrated in such a small area. I've been though this a lot, and have plenty of worn out pads and rotors to show for it.
 
Todd TCE said:
The root of this discussion (and it's a good one) is that what we are after is Brake Power (hate that term). It's actually brake torque. Or more specifically Rotor Torque.
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Personally, I am after brake torque that holds up and remains consistent for a reasonable service interval. There is no doubt that good brake torque can be accomplished with parts and kits already on the market. Whether they can keep it up for more than 10K miles is another subject entirely.
 
That's a very good point: the larger pad does offer some of that.

By mounting the caliper and pad up higher on the disc (the Er) the pad will not only produce more torque but also run hotter. That energy is concentrated in a smaller area where as a larger oe pad will spread that over a greater surface area. In fact that's one of the benefits to many oe pads and why they produce the larger shape. Conversely "race" calipers intentionally exploit these designs for their benefits also; torque to size ratio and rotor weights. Consider the rotor only need be as wide roughly as the pad is tall on the back side.

While we've had the conversation before I'll come back and say much of the pad deposit issues (not loss of torque as you mention) can be attributed to both the choice of compound and the driving habits. That elevated temp can rightly break down pad material sooner. The only ways around this are either ample cooling without pad pressure, larger pads and the necessary caliper design to house it, and the friction material stable at the necessary temps.

The cooling and release I've covered before and it's printed on all my install notes as a caution to anyone with an automatic tranny. Take it out of gear or creep hot pads. Harder to do without a console shifter for sure.

The larger pad and caliper will help. Think many oe set ups with such pads. The trade offs again become weight, caliper design, (sliders) and ability to fit various discs. Thus "adapter" brackets and cross fit ideas.

The pad choice relates to what one expects. Just like someone said before; no pad is ideal for all applications. Never will be. Surprised at the Hawk HPS comment; one of the most popular street performance pads ever produced actually. Trade offs are the issue here; wear, noise, dust lack of bite or too much. What works well at 800f is just not going to work in the morning without eating up rotors cold. But stable low temp pads are not so great at higher temps. Pads such as BP20 and Hawk HP+ try to balance that. Wilwood Poly E will be another but very metallic. For the 7416 pad there are a host of suppliers one can try as well: Hawk, Porterfield, Carbotech come to mind.

One of the down falls also of this car/kit is the lack of more rotor mass and cooling. We are saddled with a 1.10 wide disc, not a 1.25 with a wider air gap. That comes back to fit. The same pad (albeit 20mm thick not 16 to start) are used on both street and track Lightnings, and probably 8X as many Impala SS kits I've produced over the years. Both those for example do have the 1.25 disc so I'd throw it out that this is a plus.
 
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The gt500 rotor is 32mm(1.26") thick.

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If you must consider braking force in torque(which is a terrible way of measuring it) you must understand that any torque you measure, if it be rotor/wheel torque, or knuckle/caliper/pad torque is purely a bi-product, a result of friction.

The concept of automotive braking systems is to convert the kinetic energy of the moving mass of the vehicle into another form of energy. In most cases this other energy is heat. In hybrid and electric vehicles, regenerative braking is used before friction braking, turning kinetic energy into electric energy. Automotive systems convert kinetic energy into heat via friction. You can only slow your car down as much as you convert its kinetic energy into heat via friction.

Friction is the force resisting the pad from sliding against the rotor. Friction is the force resisting the rotor from sliding against the pad. Kinetic energy is the force of the rotor to move against the pad.

Fr = μN

Fr is friction, it is our stopping power.
N is normal force, this is how much brake pressure we apply to the pad.
μ is the coefficient of friction, which will be determined by your brake pad formula and their temperature.

If my car is off, and on flat ground and I press the brakes I am increasing friction. There is no kinetic force trying to move the vehicle. If I start the car and put it in drive while holding the brakes, the powertrain is now trying to move the vehicle with kinetic energy. The friction I am generating with the brakes is a greater force than the kinetic energy - therefore the vehicle does not move, the brakes do not move, no heat is generated, and the brake pad and rotor might as well be mechanically linked - this is called static friction.

If I slowly let off the brake pedal I am reducing N and therefore reducing friction. When the kinetic energy of the powertrain overcomes the force of friction the vehicle will begin to move. When the kinetic energy is greater than the friction energy the two surfaces will move against one and other - this is called kinetic friction. The amount of Fr and the distance the two surfaces move against each other will determine the amount of kinetic energy converted to heat energy.

Converting kinetic energy to heat energy is how we stop the car, the more we convert the more we stop.

If I am traveling at 30 mph(350 wheel RPM) and apply X amount of brake pressure I will produce Y amount of friction and stopping power per revolution of the wheel, and Z amount of friction and stopping power per minute.

If I am traveling at 60 mph(700 wheel RPM) and apply X amount of brake pressure I will produce Y amount of friction and stopping power per revolution of the wheel, and Z*2 amount of friction and stopping power per minute.

The stopping power per revolution of the wheel is unchanged, because Fr is unchanged and the distance per revolution of the wheel is unchanged.

The stopping power per minute has doubled because Fr is unchanged, and the distance per minute has doubled.

If we apply distance to the swept area of the rotor it is easy to understand why the same pad with the same pressure on a larger rotor provides greater stopping power.

But when we consider that pad width has decreased, and rotor diameter has increased, resulting in a similar swept area, the heat generated from friction is similar as well.

Any forces of torque(also kinetic force) applied to or from the caliper and/or rotor are a direct result of the kinetic force and friction force. Just because a caliper is situated further from the center point of the rotor does not mean torque has changed.
 
This is humorous....and why I will never make another mod for this car in the future.

It's a copy of a Baer brake kit, which has never received anything but positive reviews over the 10 years it's been available.

I'm sorry you don't like it, and I'm sorry there are potentially 19 others who are having their doubts about installing their brakes.

At the end of the day, they will only be out $155 bucks......which I won't lose any sleep over.
 
Zack said:
This is humorous....and why I will never make another mod for this car in the future.

It's a copy of a Baer brake kit, which has never received anything but positive reviews over the 10 years it's been available.

I'm sorry you don't like it, and I'm sorry there are potentially 19 others who are having their doubts about installing their brakes.

At the end of the day, they will only be out $155 bucks......which I won't lose any sleep over.
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^^^^^^^this^^^^^^^^
 
Zack said:
This is humorous....and why I will never make another mod for this car in the future.

It's a copy of a Baer brake kit, which has never received anything but positive reviews over the 10 years it's been available.

I'm sorry you don't like it, and I'm sorry there are potentially 19 others who are having their doubts about installing their brakes.

At the end of the day, they will only be out $155 bucks......which I won't lose any sleep over.
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Where is the "LIKE" button?
 
Zack said:
This is humorous....and why I will never make another mod for this car in the future.

It's a copy of a Baer brake kit, which has never received anything but positive reviews over the 10 years it's been available.

I'm sorry you don't like it, and I'm sorry there are potentially 19 others who are having their doubts about installing their brakes.

At the end of the day, they will only be out $155 bucks......which I won't lose any sleep over.
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Zack I appreciate this mod, simply because I didn't ever see how I was going to bring myself to spending $1800 on a wildwood kit. So keep doing what you are doing. I'm moving forward with my install. Only lacking calipers and pads now. Thanks for what you do.
 
Wow this thread turned into a **** show.... I have Baer brakes and will say they feel stronger, but in reality it's all about getting the brakes bled correctly. I've had three marauders and all of them had crappy pedal feel when I got them and after bleeding the brakes, they felt better and grabbed harder.

If nothing else, this kit makes the front brakes look so much better and if someone is really unhappy I might be persuaded to buy a set of brackets from them for my other marauder.
 
Zack said:
This is humorous....and why I will never make another mod for this car in the future.

It's a copy of a Baer brake kit, which has never received anything but positive reviews over the 10 years it's been available.

I'm sorry you don't like it, and I'm sorry there are potentially 19 others who are having their doubts about installing their brakes.

At the end of the day, they will only be out $155 bucks......which I won't lose any sleep over.
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Don't be so thin skinned. All I read was a discussion about various issues and experiences on brakes for a car that is notorious for problems in this department.

I'm sure it will be enlightening to see more and longer-term results with the GT500 adaptation you devised.
 
Comin' in Hot said:
Wow this thread turned into a **** show.... I have Baer brakes and will say they feel stronger, but in reality it's all about getting the brakes bled correctly. I've had three marauders and all of them had crappy pedal feel when I got them and after bleeding the brakes, they felt better and grabbed harder.

If nothing else, this kit makes the front brakes look so much better and if someone is really unhappy I might be persuaded to buy a set of brackets from them for my other marauder.
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Plus One ^^!
The kit looks exactly like the Baer kit only the rotors are dirt cheap.
The big plus for this mod is the larger diameter rotor and moving the caliper/pads out increasing the torque applied. Anybody dumb enough to want to sell their brackets can pm me - I'll pay the full price and shipping!
 
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