Ryan77

I was looking into switching to a set of slotted rotors on my '77. I was told that these would actually make the car stop slightly worse do to less surface area on the rotor, but the brakes will run cooler. Is this true? I thought that the brakes running cooler would help them to stop better, not slightly worse. Would do you guys think :confused:

BSeery

The myth about them taking longer to stop due to less surface area is just that- a myth.
Yeah, if you do the math it may make a shred of sense, but here is reality.

When you apply the brakes, the material on the pads, and rotors too, burns off a little. This produces a gas. This gas can become trapped between the rotor and pad and is not allowing pad to rotor contact. So, the slots help sweep this boundary layer away and help keep the pad and rotor in contact.
It does provide some cooling effect to the pad and rotor face as well, but not as much as say a system with ducting. The slots or some even do dimples is much better than cross drilling. Cross drilling can lead to stress fractures and pieces of the rotor can come off.

Ryan77

Thanks, that's what I was looking for. I'll be ordering a set from VBP soon to compliment my SS calipers from SSBC and SS braided hoses that are already on the car. I'll also be going to the hydroboost system soon :cheers:


[Modified by Ryan77, 6:44 PM 9/14/2003]

UKPaul

Having playing with both slots & cross drilling on brake rotors I'd choose slots. I've had a rotor fracture between holes & disintegrate under hard use (& that really isn't funny - instant 100% efficient braking, whether you want it or not! :( ). I've never heard of that happening to a slotted rotor. Braking efficiency will theoretically be reduced due to less swept area (but you'd never notice as you'd naturally increase braking pressure to compensate). Additionally, the slots (or holes) will remove any brake dust trapped between the pad & rotor quickly, thus improving braking. Both slotting & cross drilling improve braking in the wet, but I found slots were far more effective (I think water is trapped in the holes which can then get back onto the rotor surface after the brake is released. With slots the water is thrown off due to centrifugal force). The only downside I found (apart from a rotor flying apart!) was that brake pad wear increased slightly.
I don't know about any improvement due to removing the gas "bubbles" formed at high temps as I was using sintered metal pads, which apparently don't suffer so much from the problem (although they can promote high wear of the rotors, depending on the rotor material used). The major reason I tried slotted/drilled rotors was to improve wet weather efficiency, which is what they both did.
:cheers:

flynhi

So who sells a slotted rotor that weighs less than an OE 17 pounder?

Van Steel

I may be having a really good deal pretty soon on slotted rotors. I was just going to make a post about this and than i saw this thread. I just ordered 100 rotors and I'm having them all slotted and cryo-ed(heat treated). The price is going to be pretty good compared to what they are now. $139.99

LFZ

Van Steel, that sounds awesome! i'm really wanting slotted rotors for my 69! i can't wait!

wcsinx

A.K.A "fade"

perfect explanation :thumbs:

sb69coupe

According to the Baer website FAQ, neither slotting or cross-drilling is needed with modern race pads, nor is it beneficial for street driving.
http://www.baer.com/Support/FAQ.aspx#1

Ryan77

I'd be interested, I wasn't sure if you guys had slotted rotors or not, but I guess you do
:cheers:

Van Steel

Yes we have them. I'm taking them over to the machine shop tomorrow to get cut and than I'm going to cryo them. Hopefully in 2 weeks everything will be ready.
Dan

Arkansas Flash

Van Steel,

I am interested in a set of those rotors depending on their price.

Van Steel

Slotted Rotors are usually $139.99 each. I'm shooting for $100. each.

flynhi

Van Steel -
How's the slotted rotor project coming along? Do you have availability and pricing info?

flynhi

Ryan 77 - How do you like the SSBC calipers?