Power Slot Rotors

[Silv6]

Are they any good? and if so, what brake pads would ork well with it?

[mcjoslyn]

Okay, I'm sure this will start all sorts of arguments, but here goes.

If you are looking for slotted rotors for appearance, that's your choice. If you are looking for slotted rotors for performance, don't waste the money.

Here's why:

Slotted rotors first showed up on race cars. They found that at the very high speeds and extreme brake temperatures they were seeing, a layer of gas built up on the rotors when braking. This reduced the efficiency of the brakes because the pads would "float" on the gas layer. They started slotting the rotors to allow the gas to dissipate.

If you regularly perform severe braking from extremely high speeds, slotted rotors may help you. For normal applications they are actually less effective than solid rotors. Brakes work by converting kinetic energy (motion) to thermal energy (heat) and dissipating it. The efficiency of brakes is determined by how much thermal energy they can trasmit over a short period of time. The brakes pads and rotors absorb and transmit the heat through conduction and radiation. When the system reaches the point where it can't dissipate any more heat, such as after repeated hard braking, it becomes less efficient (brake fade). That's why they ventilate rotors and try to increase the swept area as much as possible with larger rotors and pads.

The problem with slotted rotors (and cross-drilled rotors as well), is that they actually reduce the swept area. By cutting slots in the rotor, you reduce the surface area. You also compromise the structural integrity of the rotor. On race cars they trade off the loss of swept area with the increased efficiency of the brakes due to the clearing of the gas layer. In a normal application you won't see the speeds or temperatures that generate the gas layer, so in effect, you are just reducing swept area and reducing the efficiency of the brakes without any gains.

You will also hear that the slots "shave" the pads which makes them more effective. That's not true. If the pads caught on the slot edges you would feel the pedal pulse, you would create all sorts of stress in the rotor/brake assembly, and you would dramatically reduce the pad life.

In my opinion, slotted rotors may look cool, but I want my brakes to be as efficient as possible. Since I don't normally drive at speeds of 150+ MPH and don't have to brake down from those speeds, I'll keep my solid rotors.

[FirebirdGT]

<blockquote>quote:</font><hr>Originally posted by mcjoslyn:
Okay, I'm sure this will start all sorts of arguments, but here goes.

If you are looking for slotted rotors for appearance, that's your choice. If you are looking for slotted rotors for performance, don't waste the money.

Here's why:

Slotted rotors first showed up on race cars. They found that at the very high speeds and extreme brake temperatures they were seeing, a layer of gas built up on the rotors when braking. This reduced the efficiency of the brakes because the pads would "float" on the gas layer. They started slotting the rotors to allow the gas to dissipate.

If you regularly perform severe braking from extremely high speeds, slotted rotors may help you. For normal applications they are actually less effective than solid rotors. Brakes work by converting kinetic energy (motion) to thermal energy (heat) and dissipating it. The efficiency of brakes is determined by how much thermal energy they can trasmit over a short period of time. The brakes pads and rotors absorb and transmit the heat through conduction and radiation. When the system reaches the point where it can't dissipate any more heat, such as after repeated hard braking, it becomes less efficient (brake fade). That's why they ventilate rotors and try to increase the swept area as much as possible with larger rotors and pads.

The problem with slotted rotors (and cross-drilled rotors as well), is that they actually reduce the swept area. By cutting slots in the rotor, you reduce the surface area. You also compromise the structural integrity of the rotor. On race cars they trade off the loss of swept area with the increased efficiency of the brakes due to the clearing of the gas layer. In a normal application you won't see the speeds or temperatures that generate the gas layer, so in effect, you are just reducing swept area and reducing the efficiency of the brakes without any gains.

You will also hear that the slots "shave" the pads which makes them more effective. That's not true. If the pads caught on the slot edges you would feel the pedal pulse, you would create all sorts of stress in the rotor/brake assembly, and you would dramatically reduce the pad life.

In my opinion, slotted rotors may look cool, but I want my brakes to be as efficient as possible. Since I don't normally drive at speeds of 150+ MPH and don't have to brake down from those speeds, I'll keep my solid rotors.<hr></blockquote>


[img]graemlins/thumbsup.gif[/img] [img]graemlins/thumbsup.gif[/img]

[camaro_speedemon]

<blockquote>quote:</font><hr>Originally posted by mcjoslyn:
Okay, I'm sure this will start all sorts of arguments, but here goes.

If you are looking for slotted rotors for appearance, that's your choice. If you are looking for slotted rotors for performance, don't waste the money.

Here's why:

Slotted rotors first showed up on race cars. They found that at the very high speeds and extreme brake temperatures they were seeing, a layer of gas built up on the rotors when braking. This reduced the efficiency of the brakes because the pads would "float" on the gas layer. They started slotting the rotors to allow the gas to dissipate.

If you regularly perform severe braking from extremely high speeds, slotted rotors may help you. For normal applications they are actually less effective than solid rotors. Brakes work by converting kinetic energy (motion) to thermal energy (heat) and dissipating it. The efficiency of brakes is determined by how much thermal energy they can trasmit over a short period of time. The brakes pads and rotors absorb and transmit the heat through conduction and radiation. When the system reaches the point where it can't dissipate any more heat, such as after repeated hard braking, it becomes less efficient (brake fade). That's why they ventilate rotors and try to increase the swept area as much as possible with larger rotors and pads.

The problem with slotted rotors (and cross-drilled rotors as well), is that they actually reduce the swept area. By cutting slots in the rotor, you reduce the surface area. You also compromise the structural integrity of the rotor. On race cars they trade off the loss of swept area with the increased efficiency of the brakes due to the clearing of the gas layer. In a normal application you won't see the speeds or temperatures that generate the gas layer, so in effect, you are just reducing swept area and reducing the efficiency of the brakes without any gains.

You will also hear that the slots "shave" the pads which makes them more effective. That's not true. If the pads caught on the slot edges you would feel the pedal pulse, you would create all sorts of stress in the rotor/brake assembly, and you would dramatically reduce the pad life.

In my opinion, slotted rotors may look cool, but I want my brakes to be as efficient as possible. Since I don't normally drive at speeds of 150+ MPH and don't have to brake down from those speeds, I'll keep my solid rotors.<hr></blockquote>

I agree with most of what you say. The only thing I don't agree with is you say slotted rotors don't "shave" the pad. I have done a lot of research on braking. Yes solid rotors are the best for performance, but slotted do shave away the pad and yes it does increase pad wear. But it does also keep the pad "clean".