my77stang

ok you guys are making me read way too much stuff

bottom line.... if im happy with stock stopping power, but i want to cool things down to prevent warped rotors (again) what do i do?

xbone

Maybe try ceramic brake pads, they are only 70 bucks and worth their weight in gold for no more blackdust, and i think they are alot easier on the rotors too. I love mine, it stops better and no dust.

my77stang

since you actually own a set of these pads and you know how they perform, might i ask which brand you went with?

also with rotors already having some discolored spots, i thought about getting them cut but is the damage already irreversable? if so do i just buy some ford rotors again?

its always more money i tell ya, anything i do, every day of my life

CrazyAl

Warped rotors usually happen when a rotor is heated unevenly,ifthey get too hot, or if they undergo a sudden temperature change.

Changing your pads won't help warping. When you brake, you are converting the forward motion of your car into heat. Changing pads won't change that. Different pads might let you brake harder or with less dust, but pad changes won't affect how how much heat gets transferred into your rotors. That is purely a factor of your car's weight and how fast you were going when you stopped.

The most common cause of rotor warping on the street is if the rotor is hot from braking and then water gets splashed on it. Avoid puddles after braking hard. If you're driving in the rain, take it easy on the brakes.

Another common cause is cheap brake rotors. Some rotors are made of better materials and better designs than others. When you are buying rotors, try and get some with a warranty. That way if they do warp, you get new ones free! Also, if you get the chance to look at them in the store, look for ones with vanes that are curvedor angled as opposed to straight. Directional-vane rotors keep cooler than straight-vaned rotors so they rotors are less likey to warp.

Also, avoid sudden hard stops.

Keep in mind that some cases of "warping" are really not warping at all...and instead is caused by having pad material transfer itself to the rotors. This happens when the rotor is very hot and you keep the car stopped with your foot on the brake. You can read more about this here: http://www.stoptech.com/tech_info/wp...rakedisk.shtml (long, beware!)

My suggestion to avoid that if you really think it could be a problem is to try a high-performance type of pad, which is less likely to transfer. You can also practice 2-stage stopping when you can. For example, if you have to brake from 50 mph to a stop, you might brake from 50 down to 20 or so (this can be hard if you want), then let the car coast for a few seconds at 20 mph (this lets the rotors cool themselves down a bit from the serious braking). Then, brake down to a stop. This way when your car is at a stop and the pads are clamped to the hot rotor, the rotor isn't super-hot.

timothyrw

CrazyAl,

First, let me say thanks, too. I've seen this post before and I've got a day free (nursing my sick fiance) so I wanted to get to the bottom of this and you've definitely argued your side well.

I read your post and here is what I think from my afternoon of research...

I've now seen pics of the brakes of Formula 1 cars and they are indeed solid. Having said that, Formula 1 cars also have high tech systems designed to "cool" those brakes. I say "cool" because those brakes glow red during races and are designed to run at a 1,000+ degrees Celcius. Also, I have read that cross drilling the rotor can weaken it; which makes sense. Certainly manufacturers like Brembo, Baer, and even Wilwood, know this in advance and manufacturer their cross-drilled rotors with that in mind.Still, all else equal, cross drilling MUST reduce structural integrity. So, it makes sense to run a full rotor if you have another system that is designed to specifically cool that rotor (like in F1). You don't have to worry about the rotoroverheating AND you don't have to worry aboutit cracking from the cross-drilling.

What it boils down to is what does cross-drilling and slotting do? Well, I've given you what Brembo and Baer say. Personally, I think they are functional (beyond weight savings) and increase performance in that they increase bite, shave/de-glaze the pad,and allow what few gases there are in modern brake pads to escape.

Having said that I think you'd need to be on a racetrack to really experience the benefits.

Bottom line.............................................. .................................................. .................................................. ........

The Ford GT has cross drilled rotors. The Corvette Z06 has cross drilled rotors. The Ferrari Enzo and FXX have cross drilled rotors. The list goes on and on. Pretty much every serious performance car has them because I think these are cars that couldLIKELY find themselves in situations where they would receive the benefits that cross drilling and slotting provide AND they don't have a seperate system designed to cool the rotors beyond maybe passive air ducts.

Ford doesn't put those brakes on a Mustang because we don't pay for them andif we want them we can get them aftermarket...

If I put on cross drilled/slotted rotors on my GT am I going to see an increase in performance on my Sunday drive in my GT over solid rotors???? Nah.... Short of running from the police (or autocross) I would never experience the temperatures and fade where it would make sense to spend that much money on them.

If I wanted to race my Mustang in autocross would crossdrilled/slotted rotors help in braking over solid rotors? I definitely think so...

Here is a very interesting article from Car and Driver. They bought 4 brake upgrade kits and put them on a Subura WRX...

http://www.caranddriver.com/features...ng-brakes.html

It's been interesting CrazyAl...

CrazyAl

Ah, I just saw this after I wrote my previous reply.

If you are seeing discolored spots, that is probably not actual warping. It is probably the pad material having been transferred to the rotor. Read the stoptech article I linked to earlier, it disucsses this much better than I could. A different type of pad might very well help!

wingman75

I would like to get rid of the brake dust too. The worst part of cleaning is tring to get the dust out from behind the spokes. What brand pads are yours and where did you get them.

Thanks

Stoenr

Stock rotors with upgraded pads,lines,and fluid worked great for me on a HOT June day at the track. Was so hot temp guage was going up to 3/4.
No "warping" what so ever, very little fading if any.
I plan on going with upgraded rotors when these are toast, but it will be totally for cosmetic, until then, stock rotors for me at the track.

CrazyAl

Thanks to you too for the discussion!


I also feel the need to make an important distinction here. You've been gathering information from sources like Brembo and Stoptech and articles regarding aftermarket brake kits. You have to be very careful here, becasue you don't want to end up comparing apples and oranges. There is nothing wrong with that information per se, but it does confuse the discussion.

This discussion was originally aboutdrilled/slotted rotorsVS solid rotors as a general concept. When you start talking about specific brands/partsthat is a different thing entirely.

I have explained how a drilled rotor is weaker and has poorer heat handling than a solid rotor of the same size. The point of that argument was to refute the claims made in the OP post regarding why rotors aredrilled. (As we have discussed, drilling has nothing to do withimproving heat handling capability)

The concept "of the same size"is critically important. Does it mean that all drilled rotors are inferior to a given solid rotor? Of course not.

My main point in all of this discussion has to do with the OP post. Cross-drilled rotors have nothing to do with "better cooling". And slotted rotors do not "warm up faster and dissipate heat better". My main point here,throughout the thread,has simply been that the OP post is completely wrong. Am I saying people shouldn't use drilled rotors in general? Not at all.

For example: We have a late-model Mustang GT. We swap out the OEM rotors and we install some OEM-size drilled rotors just like what was in the OP photo, keeping all the rest of the hardware stock. What happens?

We would get a very small decrease in rotating weight. We might get a little "pad scrubbing" and perhaps some resistance to outgassing. But I'd be willing to bet that these effects would be so miniscule that a typical driver would never notice them. This is exactly the kind of experiment that I performed back in grad school on the brake dyno. When testing the kind of change, the results are clearly indicitive: A drilled rotor and a non-drilled rotor of the SAME SIZE have no significant difference in braking performance (brake torque and fade). In other words, taking a rotor and drilling it does not make it a better rotor as far as braking performance is concerned. Tests like this are documented in the SAE book I mentioned above, should you want concrete proof with data and so forth.

Now then, installing a kit from Baer or Brembo or Wilwood in our Mustang(for example, the posts you made earlier and the Car & Driver article you linked to) is a totally different thing. In this case we are changing many variables at once. We are changing calipers, the rotor diameter, the rotor material, the rotor thickness, and of course the design of the rotor. In this situation we will get a lot better braking, and these kits typically have drilled rotors. Does this mean that "drilled rotors arebetter than solid rotors". Not at all. Scientifically, this experiment is poorly conceived. Itproves only one thing:the WHOLEKIT we installedperforms better than the OEM setup. But it does not explainthe how-and-why.To do that you musttesteach part individually.

I'm not going to talk about calipers and such becasue it's not relvant to this discussion. But we are talking about rotors, so let's compare a "big brake kit" rotor like the Baer or Stoptech ones that you've brought up. Those rotors are typically 14" in diameter for the Mustang applications--that's a lotbigger than stock.A large diameter rotor like thatis the best thing goingbrake for improving brake torque. So right off the bat, this 14" rotor (drill or no drill) has better braking performance than our OEM disc simply due to its diameter. A larger rotor like that islarger inarea than the stock rotor and is also a lot heavier. This means more area for shedding heat anda larger thermal mass to better handle thermal stresses. These things are what makes a rotor durable. A bigger, heavier, rotor can better handle the thermal cycling of brake systems. Now, here's the kicker. Becasue these 14" discs are so much bigger than the OEM rotors, you can drill them quite a bitand get a lot of weight savings....and even after all that drilling they are STILL heavier and stronger than the OEM disc (becasue they are larger). The drilled 14" rotor is still more durable than the OEM rotor, but it is not as durable as the solid 14" rotor.

So:

An OEM-replacement style drilled rotor (PowerStop) is essentially no better than the OEM rotors, which is the whole point I have been making the entire time.

Of course, a "big brake" rotor like the Baers, Brembos, and Stoptechs that you have mentioned are clearly superior to the OEM rotors. These rotors happen to be drilled. But the drilling is not WHY they are better. They are better becasue they are larger. And they are so much larger that they are ABLE to be drilled for weight savings, while maintaininggoodthermal-handling ability.

But, as always,drilling the rotor does weaken it. In the very serious braking applications like Nascar and Formula, etc, they use solid rotors becasue in these situations the loads are so extreme that they areNOT ABLE to drill them. (As we have discussed before, drilling a given rotor decreases that rotor's durability).

OEM rotor: baseline
OEM-type drilled: effectivley the same.
Big-brake kit drilled: Significant improvement.
Big-brake kit undrilled: Even better braking, but overkill.

ZZmustang

CrazyAl.
If your last post was your first post you would have no reason to apologize.
You were correct that My first post was a cut and past but that’s no reason to say, "Actually, this post is one of the biggest piles of BS that I have ever seen! "
The post was cut-N-paste but just like your information it was put out there for discussion, You don't want to comment, don't, you don't want to read it, don't, A topic is just a topic, Your last post made since, and I have never been for any slotted or drilled rotors, it was (again) for discussion.
So when you start a thread I should come to your thread and state, "Actually, this post is one of the biggest piles of BS that I have ever seen! " and then I could post in a few days that "crazyal , if I offended you, I apologize." and every thing would be just fine?
Some people on this site are so narrow minded that there OPINION is the only way that should ever be considered, that’s sad,
Hears a good example from NicksEZ.
"I can't even understand why this post was started. At least be right about the topic if you start it. I only know the basics about brakes andI knew that the first post was b/s...."
Be right about the Topic? The topic is Slotted and drilled Rotors, and that’s what the post is about, so? and He can't understand why the post was started? AHHH why is any post started?
Crazyal, just switch my name with your on the first two post and you can understand. But maybe not.