why hasn't anyone made there own oversized brake kit?
07-12-02, 02:39 AM
#1
John
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why hasn't anyone made there own oversized brake kit?
Has anyone put together there own brake kit? You can buy custom 13" rotors under $300, rotor hats cost about $150, Willwood 6 piston calipers under $700. And stainless lines for $100. $1250!! There's probably a reason why people have not done it though.
What would happen if you just upgrade the rotors and left the stock calipers? Would there be any advantages? I would think you would get less brake fade and warp, would it decrease 60-0?
What would happen if you just upgrade the rotors and left the stock calipers? Would there be any advantages? I would think you would get less brake fade and warp, would it decrease 60-0?
07-12-02, 02:54 AM
#2
Super Snuggles
You left out custom brackets to mount the calipers, and that's the sticking point... how many people want to or are able to fabricate a bracket to correctly position the caliper in relation to the rotor? Then again, how many people want to be responsible for the brake system, the one thing you really don't want to screw up? 
"Upgrading" to slotted or drilled rotors with stock calipers look good, but there's no real benefit and modern brake pads don't "gas" to the same degree that old materials did, so the venting argument is null. You're also not reducing weight to any significant degree, so there's not even a performance benefit there.
And no, 60-0 will not decrease. Here's a post I made in a different thread that should tell you all you need to know...
"Upgrading" to slotted or drilled rotors with stock calipers look good, but there's no real benefit and modern brake pads don't "gas" to the same degree that old materials did, so the venting argument is null. You're also not reducing weight to any significant degree, so there's not even a performance benefit there.
And no, 60-0 will not decrease. Here's a post I made in a different thread that should tell you all you need to know...
The only time that a larger brake kit will decrease your stopping distance is if your original braking system was already experiencing fade.
Brake from 70-0 once in a heavy car (let's say it's a 4,000 lb. Impala SS) and it is possible that you'll experience some brake fade even during the first stop. Therefore the normal stopping distance for that car includes some extra distance due to an inadequate braking system.
For example, let's say 70-0 requires 175 ft. for this car.
However, if you upgrade to a larger brake kit, you will eliminate the fading problem and reduce your stopping distance to what it would have been if no fading had occurred. In other words, "normal" operation of the braking system. Make sense?
Let's say 70-0 in 175 ft. now becomes 70-0 in 165 ft., the distance it takes the same car to stop without fade.
If you brake hard from 70-0 once in a lighter car (like a 3rd gen.) the stock braking system is more than adequate, so there's no brake fade and therefore no need for a larger braking system, nor will one stop the car more quickly. In fact, you'll only be increasing unsprung weight unless you go to considerable expense to buy special lightweight components.
Let's say 70-0 requires 121 ft. in a 3rd gen. RX-7. And 70-0 remains 121 ft., even with the addition of a big brake kit.
But, if you increase the width/stickiness of the tire or reduce the weight of the car, you will reduce your braking distance.
Now 70-0 in 121 ft. might become 70-0 in 118 ft with some wider than stock Kumho Victoracers, for example.
Brake from 100-0 repeatedly with the stock brakes on the RX-7 (or drive in a long road course event with multiple sharp turns), and you will get gradually increasing fade as the brakes get hotter, and braking distance will increase correspondingly.
Now if you install a big brake kit, the increased surface area of the rotor will help to cool the brakes more effectively, reducing brake fade and once again returning stopping distances to "normal".
So in summary; big brake kits are not necessary unless/until the brakes they are replacing are unable to dissipate heat adequately enough to prevent fading.
If the brakes have sufficient clamping force to lock and keep the wheels from turning (or trigger the ABS system), only the friction between the tires and the road is stopping the vehicle. Therefore stickier/wider tires will help decrease stopping distance.
And finally, it is easier to bring a lighter mass to a stop than it is to bring a heavier mass to a stop. Therefore reducing weight will also help to reduce stopping distance.
Brake from 70-0 once in a heavy car (let's say it's a 4,000 lb. Impala SS) and it is possible that you'll experience some brake fade even during the first stop. Therefore the normal stopping distance for that car includes some extra distance due to an inadequate braking system.
For example, let's say 70-0 requires 175 ft. for this car.
However, if you upgrade to a larger brake kit, you will eliminate the fading problem and reduce your stopping distance to what it would have been if no fading had occurred. In other words, "normal" operation of the braking system. Make sense?
Let's say 70-0 in 175 ft. now becomes 70-0 in 165 ft., the distance it takes the same car to stop without fade.
If you brake hard from 70-0 once in a lighter car (like a 3rd gen.) the stock braking system is more than adequate, so there's no brake fade and therefore no need for a larger braking system, nor will one stop the car more quickly. In fact, you'll only be increasing unsprung weight unless you go to considerable expense to buy special lightweight components.
Let's say 70-0 requires 121 ft. in a 3rd gen. RX-7. And 70-0 remains 121 ft., even with the addition of a big brake kit.
But, if you increase the width/stickiness of the tire or reduce the weight of the car, you will reduce your braking distance.
Now 70-0 in 121 ft. might become 70-0 in 118 ft with some wider than stock Kumho Victoracers, for example.
Brake from 100-0 repeatedly with the stock brakes on the RX-7 (or drive in a long road course event with multiple sharp turns), and you will get gradually increasing fade as the brakes get hotter, and braking distance will increase correspondingly.
Now if you install a big brake kit, the increased surface area of the rotor will help to cool the brakes more effectively, reducing brake fade and once again returning stopping distances to "normal".
So in summary; big brake kits are not necessary unless/until the brakes they are replacing are unable to dissipate heat adequately enough to prevent fading.
If the brakes have sufficient clamping force to lock and keep the wheels from turning (or trigger the ABS system), only the friction between the tires and the road is stopping the vehicle. Therefore stickier/wider tires will help decrease stopping distance.
And finally, it is easier to bring a lighter mass to a stop than it is to bring a heavier mass to a stop. Therefore reducing weight will also help to reduce stopping distance.
07-12-02, 04:03 AM
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John
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OK, makes sense. If I'm already able to lock up my brakes or trip the ABS, there is no need for even more braking. So say I just change to larger rotors and keep my calipers, will I have any advantage from say 100-0 or even 120-0, basiclly very high speeds? I've always thought brakes on my FD were awesome, just gets alittle scary when you go over 100 or so. Plus I need something to fill in my 19" wheels
07-12-02, 04:55 AM
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07-12-02, 02:23 PM
#6
Super Snuggles
Originally posted by RedTT
OK, makes sense. If I'm already able to lock up my brakes or trip the ABS, there is no need for even more braking. So say I just change to larger rotors and keep my calipers, will I have any advantage from say 100-0 or even 120-0, basiclly very high speeds? I've always thought brakes on my FD were awesome, just gets alittle scary when you go over 100 or so. Plus I need something to fill in my 19" wheels
OK, makes sense. If I'm already able to lock up my brakes or trip the ABS, there is no need for even more braking. So say I just change to larger rotors and keep my calipers, will I have any advantage from say 100-0 or even 120-0, basiclly very high speeds? I've always thought brakes on my FD were awesome, just gets alittle scary when you go over 100 or so. Plus I need something to fill in my 19" wheels
Mandeville Racing made a kit which retained the stock calipers, but installed a spacer in between the two halves to allow the use of a thicker rotor. It also included a bracket to relocate the caliper to clear the rotors larger (than stock) diameter. One benefit is price, obviously, since you get to re-use the stock calipers, but the surface area of the rotor is increased which will help dissipate heat more effectively than a smaller rotor, which is the most important benefit of a big brake kit.
Ideally, the braking system should retain enough heat to make the pads work efficiently in the temperature range for which they were designed, while being large enough to dissipate the extra heat of repeated braking cycles to keep the brakes from fading, which increases stopping distances.
By upgrading proportionately, I mean that there is already an imbalance or bias towards the front inherent in the stock system. Upgrading only the front brakes to a larger kit makes this imbalance even worse, which can overheat (boil) the brake fluid during track-style braking usage, and reduce braking effectiveness. Alternatively, upgrading the rear brakes too far can be very detrimental to braking stability, so don't overdo it in either direction.
Maintain a piston area ratio a little better than stock, and you'll be all right. The stock ratio is approximately 4:1 front to rear I've been told, but I have not confirmed that myself. In that case, roughly 3.7-3.8:1 would be a better ratio.
You can determine piston area ratio by calculating the piston area for both front and rear and then dividing the area for the front by the area of the rear. The piston area for a caliper is the the total area for one side of the caliper. Treat a single piston caliper (like the rear caliper on the FD) as a 2 piston caliper.
Example:
Piston area = Pi * radius ^2 * half the number of pistons
For a front caliper with four 1.75" diameter pistons...
Piston area = 3.1417 * (.875 * .875) * 2 = 4.81 sq/in.
For a rear caliper with one 1.65" diameter piston...
Piston area = 3.1417 * (.81 * .81) * 1 = 2.06 sq/in.
Therefore the ratio front to rear would be 2.33:1 in this example. (4.81 / 2.06 = 2.33)
07-12-02, 04:55 PM
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I am working on a cheap alternative to the 2000+ brake kits. I made an interesting discovery, the stock 3000gt calipers are noticably bigger than the fd. They also use nearly the same monting ears. They also clear the stock wheels. Price $75 a piece from mitsu recycler. Now I just need to make hats.
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