DeathCougar

iTrader: (23)

Look. Somehow, this turned into a flamefest thread with much ill-feelings. Yota is a place for Info, not sarcasm and flaming. I appreciate all opinions, facts, and real world opinions, but lets try it without gettin our panties in a bunch guys!

I will gather what I can from all the posts, and post my results when I do the work. Keep the Info coming!!!

Flygtenstein

I have not flamed anyone.

You have gotten some great info.

I too have learned something, apparently the 62 rotors will work on IFS. I have the IFS calipers on my solid axle with the 62 rotors.

1 foot or 1 inch is enough to be the difference from crash or safe.

Please, report back with all necessary statistical data.

thefallman

no what he said is if your bringing "theorhetical" science into it while ignoring real world "experiance its silly.

BTW the one benefite and its a major one when talking about breaking is Rotating Mass

when you drill and slot you reduce that mass by a significant amount.

so the science of it isnt just surface area its alot of things including heat sinking ablity and head disipation ability as well mass and other things all figure into the SCIENCE of it.

there is a reason Road, Drag, Autocross, ect

im not talking about professionals they do other things to remidie these issues because they have lots more money. im talking about weekend warriors. go to a few races and check it out.

FredTJ

A couple of other things, then I'm done on this one.

From Baer's web site:

"
In years past, cross-drilling and/or slotting the rotor for racing purposes was beneficial by providing a way to expel the gasses created when the bonding agents employed to manufacture the pads began to break down at extreme temperatures. This condition is often referred to as "green pad fade" or "outgassing". When it does occur, the driver still has a good firm brake pedal, but simply little or no friction. Since this normally happens only at temperatures witnessed in racing, this can be very exciting! However, with today´s race pad technology, ´outgassing´ is no longer much of a concern. When shopping for races pads, or even ultra-high performance road pads, look for the phrases, "dynamic surface treatment", "race ready", and/or, "pre-burnished". When these or similar statements are made by the pad manufacturer, the pad in question will likely have little or no problem with ´outgassing´. Ironically more pedestrian pads used on most streetcars will still exhibit ´outgassing´, but only when used at temperatures normally only encountered on the racetrack. Although crossdrilling and/or slotting will provide a welcome path to expend any gasses when and if they develop, it is primarily a visual enhancement behind today’s often wide-open wheel designs.
Slotted surfaces are what Baer recommends for track only use. Slotted only rotors are offered as an option for any of Baer’s offerings.
"


And a link to a short rotor discussion from several well known brake engineers and brake manufacturers:

http://flashoffroad.com/Maintenance/...akeRotors.html


Interestingly enough, on my 4Runner, which I've had for what, about a month now, and in perfect timing to this discussion, the wear indicators starting rubbing the rotors yesterday.
Today I replace the pads with Raybestos ceramics. The rotors looked ok (though are close, so I may replace 'em next week or so), so, for now, I deglazed them a bit. While I was at it I adjusted the rear brakes and adjusted the LSPV.

Took the truck out and had the new pads bedded in about half an hour.


The truck will plant your face on the windshield without seat belts.
It's one of the best stopping vehicles I've owned. The Jeep, previous to this, was as good only after a massive front end/brake upgrade (WJ knuckle and brake {dual piston calipers compared to the stock single piston calipers} swap).

Lastly, for those who may have commented about "real world" experience (I've not read all of the posts, simply skipped through some of them), I have that with cross drilled and solid (vented). I switched to cross drilled on the Jeep and experienced less stopping power so swtiched back to solid (vented).


Best,
Fred

Yoda

I don't believe FJ60 rotors work on IFS!!

I have the solid axle on my cruiser. I upgraded to the 95 4Runner calipers. These are slighty wider than the cruiser's. 4Runner calipers have a different offset (for lack of a better term)

DeathCougar

iTrader: (23)

Im sure they dont, but was I never even looking to put FJ60 rotors on my rig. I wanted 95 4runner rotors.

mastacox

Well, I'd just like to sneak my 0.02 in on brakes...

First: slotted brakes will degrade your pad life because they were developed to quickly take glazed layers off of your pads and get you to fresh pad to stop quickly.

Second: drilled and/or slotted rotors will give you enchanced braking capabilities in wet conditions, especially on initial application when the braking surfaces are wet and cold. This is a big advantage IMO. Additionally, the rotors will probably give you better overall braking characteristics in mountainous conditions, where brake temps can reach very large values in emergency stop situations.

Third: friction is generally independent of surface area, especially when the materials in question are very rigid and resistant to shearing. In my estimation, the reason larger braking surfaces allow greater stopping force is not because there is more area, but because you can fit more pistons behind a larger pad (in addition to the fact that a larger rotor will be able to create a larger moment at the wheel). I would say that two different sets of pads (made with the same material, just different surface areas) with the same pistons, rotors, and geometries holding them, will display similar (if not identical) braking characteristics. Any differences observed will likely have more to do with heat transfer than friction, and temperature-dependent properties of the materials involved. While wer're talking about this; slotting/drilling rotors doesn't take very much of the overall surface area away anyway.

Fourth: with respect to heat transfer and fluid flow, I think that there is a consideration people haven't thought of, mainly that a cross-drilled/slotted rotor will tend to have more turbulent flow over its surface (especially with slots, which would break up a no-slip boundary layer), enhancing cooling. Additionally, a drilled rotor will have cooler spots around the holes, as they are being cooled by air flow just as the vents in the rotor do.

In my estimation, a drilled/vented rotor will have somewhat superior cooling characteristics to a simply vented rotor. Slotting, however, probably doesn't do much for you except scrub your pads. Overall, I will be going with drilled (and of course vented) rotors when I need to change them out to assure I have the best possible braking for the mountains here in NNM and CO, as well as better braking ability in wet conditions.



EDIT: Oh and by the way, anyone saying their 4Runner is the best stopping vehicle they have ever driven because it will fling them into the windshield, needs to drive a 2005 Audi A4 with the sport braking package. THAT thing stops on a dime.

rockota

I've run both. Choose what you like and prefer. But if you run in a lot of mud, consider staying away from slotted or drilled as they have a tendency to pack with mud and wear on your pads. I prefer solid myself for a DD; it's a personal preference.

Back to my question; anyone know the true difference between the 95 4Runner calipers/rotors and the pre-95? I'm still trying to track this down... Thanks!

trythis

I am going to share my opinion and dissagree in a flame-free cool- freindly way and say that the surface area is important directly and indirectly. The wider the surface the more friction the pads/pistons can get and the less you have to push to get stopping power. If you reduce the width of rotor surface to 1/4 inch, your pistons/ pads will have to use a lot more energy to get the same amount of friction as 2 inches of rotor. Diameter is the indrect part of this: The larger the diameter, the larger the outside circle. This makes a better rotor in the same way a longer pipe makes a better breaker bar. larager diameter is the same as a longer cheater bar. There is my attempt at adding science, please don;t feel attacked or anything

someguynamedmat

Rather than starting a new thread, I'd thought I'd ask some questions here. So here goes. I am in the process of doing a majot front end overhaul as well as brake upgrade and am looking at various parts, pads, disc, etc. So the facts are this:

Fact 1: I have a 1990 4runner 3vze w ~200k mi on it. 15" wheels with goodyear fortera silent armor 31x10.5's, and IFS.

Problem: There are multiple sizes for brakes, but what sizes will fit the factory calipers? ie http://replacement.autopartswarehous...20Disc&dp=true
There are multiple diameters ranging from 289-319mm and thickness ranging from 18-23mm with height variants from 64.5-70.3mm. Which one will work with what I have? I had no idea that the stock 16" rimmed vehicles had larger brakes. Did anyone else? So please help me out with this. And also, I plan on getting at least vented discs, but dont know if i will go so far as slotted.

Problem 2: I nee to know if this http://www.allprooffroad.com/index.p...ask=view&id=33 brake kit will be the best bet or if there is another better alternative.

Problem 3: I plan on getting EBC green stuff for my brake pads. Is this a good idea, or is getting antoher brand a better idea. If so what brand?
So again, HELP!

CRamsey

iTrader: (1)

Been doing a little research on brakes and I have a question. I have a 1988 4Runner, 22RE, 5spd. I'm going with the LC Engineering slotted/cross-drilled rotors in an effort to avoid the warping I've had on the last couple sets of stock rotors.
My question is: What's the best type of pad to use with these rotors? I generally drive in the city, lots of stop and go, sometimes have to slam on the brakes. This has led to my warping problem.

Thanks, Craig in NC

DeathCougar

iTrader: (23)

you have found my thread for me...excellent! I was looking for this one...

I'd say stock pads, or TRD pads if they make them. I plan on using stock pads from a 1995 4Runner, or TRD pads if I can find them. Less noise and very little if any brake dust.

btw I will be doing this swap soon...SOON i say! its summer now Huzzah!

FredTJ

And how do you figure that slotted/crossed drilled rotors are going to help ?





Fred

intense

Thank you!! Finally someone else that knows the truth. As an example, name one professional racing team or series that employs cross-drilled rotors...easy answer, none! I have seen slotted rotors on Champ car before, FTR.

intense

Agreed, cross drilled will only increase your chances of warping. The holes in the rotors will create hotspots on the rotor, making them more prone to cracking and warping

DeathCougar

iTrader: (23)

Every Super Figure 8 car that runs locally here uses them. And those cars are ALWAYS on the brakes.

JackMhigh

Use the master cylinder off of a 98 T100. I work at a parts store and i look around when I'm bored. She's the biggest one that would work on our trucks. If you want I can get you a Wagner part number (It's remanufactured) just pm or email me. My job kicks ass, I can get reman. calipers for only $15 a piece and a lifetime warrany.

FredTJ

Biggest as in biggest diameter bore ?
You realize, don't you, that the bigger the bore, the *lower* the line pressure for the same amount of foot pressure on the pedal, right ?




Fred

Yota82

The whole point of drilled/slotted rotors is not to help cool the rotor but to degas. When the pads get hot they emmit a gas that builds up between the pad and the rotor which prevents the pad from making full contact with the rotor. Drilled/slotted rotors work better to prevent brake fade. It won't help warpage.

FredTJ

That's correct, and since there is virtually no outgassing on modern day pads, the whole point of cross drilled rotors is moot, with the exception of maybe "bling, bling" for those who think that they look cool.

Also, crossdrilling really reduces the surface area of the rotor, by as much as maybe 25% which really reduces the effectiveness of braking.

Braking works by transfering kinetic energy to heat and it does that by friction, friction of the pad surfaces against the rotor. Less surface area = less friction = less braking efficiency.

Braking efficiency depends on the mass of the rotor as the rotor acts as a heat sink.

Crossdrilling decreases the mass of the rotor. Less mass = less braking efficiency.



Fred