OGRacing

iTrader: (1)

this was caused by a Motorsports OEM abs unit failing.

cyotani

iTrader: (8)

I got a one.

Slotted, drilled or normal rotors?

OGRacing

iTrader: (1)

Slotted or blank, never drilled.

The rotors entire job is to dissipate heat. It takes the energy and tries it best to cool itself to be ready for the next rotation. when you see a glowing rotor you want to see that orange ring right in the center of the rotor. if you see the heat in the center of the rotor that means the rotor is dissipating the heat fast enough away from the edges of the rotor. the edges are the weakest points of the rotor that's why having excessive heat in them is bad. bands are bad, you don't want to see multiple bands. if you see that that means the rotor is not controlling the heat. that usually means the caliper is failing or poorly engineered. sorry if i'm typing like a cave man it's been a long day lol. anyway onward.

in Road racing I'll install slotted rotors. when picking out a rotor you want to see the pattern moving outward. the slots will remove Superheated particles out and away from the pad rotor surface. this will aid in cooling. if your going to race in the mud, rally, or rain. then you will want a blank rotor. the mud races i go to that clay gets everywhere. you'll find it 3 days latter in between your fingers. it will get into the grooves of the rotor.

Drilled.. shoot me. i've been talking to people about how awful drilled rotors are. All i get in response is "are you sure?". Yes, I'm flipping sure that drilled rotors are crap. Fact of the matter is it cost 3x less to drill a hole then it does to cut a slot (that's why the oem's do it) . Someone decided that "I'll cut my rotors to look like racing rotors.. but all i have is a drill press" and then the drilled rotor was born to make my life harder. Sorry i'm normally a more positive person... The holes are said to release gasses. i have no clue what gasses they are talking about, i'm sure they don't exist, and an marketing major came up with that quote. the holes themselves actually remove a lot of material from the rotor. This material is desperately needed for the rotor to cool itself. think of it this way it's easier to start a log on fire if you put the flame on the thinnest part of a log. because the rotor has less thermal capacity and is easier to heat up it will be easier to fail. yes i'm sure...

OGRacing

iTrader: (1)

I got a Picture of what i'm talking about, with rings. the PFC rotor is heating nice and even, as where the j hook is starting to flex and distort.

cyotani

iTrader: (8)

Thanks for the response!

this is from ebc brakes website:
When brake fade occurs the brake pad is actually skidding on a film of gas created by the over heating of the constituents of the brake pad. This does not always mean a poor quality brake pad has been used and in performance use pads can fade due to overloading the brake pad compared to its design targets. "

But from what I have heard that was a thing of the past a now days the only brake fade most people have to worry about is brake fluid reaching it's boiling temp. Also, the slot in the middle of most brake pads is supposed to help with that function. So idk how much validity the gas escape theory has.

OGRacing

iTrader: (1)

Yea that's EBC.. you want to see a "race pad" catch on fire you know where to look. any brake company that paints a rotor is a joke and should not be taken seriously.

most brake fade is wrong pad - wrong application. People pushing a pad too hard and overheating it. i've seen 1600* on autozone pads. they weren't working at that temp but they they did get there. Most of the street pads have "fillers" i have no idea what "fillers" are, Wood , earthworms, old factory workers. the fillers are combustible. Combine earthworms with a pad that's failing to stop a car, creating tons of heat, and you got a fire. yes at the point the fluid is boiling, and the calipers are certainly shot too.

Leafy

iTrader: (1)

Really cant believe they posted that on their site. I thought organic binding agents which outgassed when hot went the way of the dodo with asbestos based brake pads in the 80's. Surprised OG didnt know this was the original reason behind drilled and slotted rotors.

Can confirm EBC arent all that great with heat, I warped a pad backing plate on the rears of the auto-x car for their red pads. Real good pedal feel and modulation from them though. If you're not pushing their pads heatwise they blow hawk out of the water.

OGRacing

iTrader: (1)

Antimony - Wikipedia, the free encyclopedia
Antimony Is still heavily used and found in brake pads, so is copper. Both when burned will offgas Toxins. Antimony has been linked to severe birth defects, cancer, and we are still learning more about it. almost every brake pad manufacturer uses a high amount of antimony as it stabilises led during high heat operations. you can see it in the pad. it is the silver metallic substance.
PFC Does not use copper or antimony in any of it's applications.. If your telling me that that offgas prevents braking then you have some serious decrepit pads. you need to change pads, not drill holes in a rotor. also think about what pads you're using next time your changing a wheel.

hornetball

iTrader: (4)

The picture you posted with "OEM ABS Failure" on the last page is the perfect illustration of what drilled rotors do.

mr_hyde

iTrader: (4)

How precise do the weights need to be? It would seem the center of gravity of most all NA/NB chassis would be similar and the corner weights would be withing a percent or two for most of our cars. The only big variable would be total curb weight.

I'm at a braking crossroads with my car. I have been running different combinations of Carbotechs since I started getting fast and I love the bite and their ability to remain consistent for 20-30 minute sessions. I have never felt a hint of fade even when abusing them consciously. I am on OEM sport calipers so a 4 wheel BBK would offer some improvements but I'm not dissatisfied with what I have been running. I'll continue to monitor this thread and my quarterly bonus checks to see if I can drop the coin over the winter and if so, what combination to buy.

OGRacing

iTrader: (1)

On all the miata chassis it will be close. tire size, ride height setting, location of turbo & supercharger, and even roll cage design could efficiently change the location of the center of gravity. i would need something exact to the nearest inch.

Nate99

Awesome info here, thanks. I have Xidas, so I can adjust the bump/rebound in the front. Will definitely give that a shot next time. Can I check runout on the rotors off the car, or do they need to be mounted on the hub when I check it?

I have the Wilwood prop valve already, which is currently adjusted about one turn off of max rear bias. I can probably dial a bit more toward the rear also, but I'm not sure if that will solve the feel problem.

I'm open to trying some other compounds, but I get Hawks for free - are there any Hawk compounds you would recommend? If not I'm game for trying the PFC01 as you mentioned.

Savington

iTrader: (31)

How much deflection are we talking about here? .002 or .020 or more?

OGRacing

iTrader: (1)

That really depends,
1) what kind of rotor is it (1 piece or 2 pieces)
2) how well was it designed to prevent coning
3) how shitty is the casting
4) exactly how hot it got

For a truly Terrible, single piece rotor, that is very hot. 2mm at the OD is not out of the question. (.08"-.07") that's at first form of deformation (coning). it gets worse the higher you go threw the the wave patterns.

OGRacing

iTrader: (1)

you said you were running 60's F&R. that would be the compound i would recommend. hawk pads elevate too much TQ with heat to try and manipulate F&R balance. Throw a set of DTC70's in the back and the TQ levels could criss cross threw the temperature range.

Nate99

Cool, thanks for all the help. I'll try some of your suggestions at the next NASA event (in Jan).

OGRacing

iTrader: (1)

lol yea it is the end of the season. anyone else have questions?

TurboTim

iTrader: (9)

Awesome thread.

My goodwin Gen 1 BBK (two piece rotor, dynalites) still squeals on the street, always had. Solid rotors. I tried the original wilwood Q pads and have EBC greens on it now, tried various companies anti squeal goop and still squeal when coming to a stop. I was going to try aluminum backing plates for the pads but never did. I want my fake race car to stop like a street car. Help?

acedeuce802

iTrader: (1)

All the big brake kits that I've seen use solid mounted calipers. The rotors are also solid mounted. Generally, one of the two needs to be floating, or at least semi-floating. Why is this acceptable for the off-the-shelf big brake kits? Pads and rotors don't wear exactly evenly, and there needs to be allowable play to keep the caliper centered within the rotor, to promote even pad pressure, and reduce drag.

OGRacing

iTrader: (1)

TurboTim,
Brake squeal is cause by two things, and it's best if we think about the braking system as a speaker. the Pad would be like the magnet. the vibrations of the pad are very small. On it's own you might not be able to hear it. the Rotor is like the speaker cone. it takes that little noise and amplifies it. so the problem might not only be your pad.

Allot plays into the small vibrations. pad materials, contamination, the taper of the pad. most street pads have noise fillers. they make the pad"soft" and allow the pad material to absorb small vibrations before they make a noise.
contamination. I hate EBC because they contaminate their pads from the factory. the rotors and pads are covered with paint. you have 0 chance of having an non contaminated braking system. those little pits of paint can cause a vibrations and play havoc on performance.


Pad taper!! ever wonder why street pads have a taper to them? when a pad is making contact with a rotor it submits a frequency. the pad taper is there it's to limit the amount of frequencies that are generated by a pad. Engineers can change that taper to change the frequency. They try to put that noise up and out of the frequency humans can hear. Race pads don't have tapers. because race cars love dem squeally brakes.

...


Rotors
A poorly constructed rotor can take those small vibrations al make it that much louder. another reason to not have drilled rotors. it removes the material needed to make a rotor thermally stable.

Do yourself a favor and make sure the rotors are tight to the hats. the bolts could loosen up a little bit and that would make noise. other than that, you can look to some ceramics. if you look to changing your pads look at the Wagner ultaquiets. wagners where my big competition to the PFC Z rated pads. I know PFC doesn't have a Z rated in 7752 pad shape ( dynalights) or i would recommend those.