Brake options

maroon_185

New member
I was wondering just what all is out there for out cars brake wise. I was mainly curious about what is out there that will bolt right up or with little modification.

Thanx
 

Gary

Moderator
From the top of my head,
ST185
Upgrade: Porterfield R4S pad, Goodridge SS line, TRD pad (discontinued), KVR slotted rotor, Motul fluid, etc...
Brake kit:
Wilwood kit from Rocketeer (need 17" rim)
ST205 caliper, front need modification, rear bolt on.

For ST205 front caliper, it will be easier if you machine the rotor off. Otherwise, you will need to make a custom bracket.
 

maroon_185

New member
I was mainly looking for caliper upgrades, something that will work with my 16" rims, IMO 17" is too much mass to far away from the hub to rotate.
 

Griffin

New member
maroon_185":1tmuq7lr said:
I was mainly looking for caliper upgrades, something that will work with my 16" rims, IMO 17" is too much mass to far away from the hub to rotate.

Not if you get the SSR Comps - they are super light.

anyways I went with the goodrige SS lines, slotted OEM rotors, and porterfield R4S pads and it was a HUGE improvement. I do want to go to the rocketeer kit though, as I would like to reduce the fade I get after a while if I'm pushing really hard though a long canyon run.


anyways I think the ST205 came with 16 inch wheels - so the ST205 brakes may be an option for you.
 

maroon_185

New member
Yeah I plan on getting slightly bigger vented disk and better pads, But what is a good front caliper replacement? I apologize for being kind of vauge but I just need to know what calipers will work good with our cars.

For example does
rotora
stoptech
brembo
or baer maek caliper replacements that fit with little to no modification.
 

CMS-GT4

Active member
I am selling a good brake kit option. used the same parts as the rocketteer kit except I used 12" rotors, and a bracket needs to be fabricated.
 

roo

New member
Slotted or cross-driled rotors, Top Secret pads, and you can say goodbye to brake fade.
 

Darth Boost

New member
Griffin":2bbbrunk said:
roo":2bbbrunk said:
Slotted or cross-driled rotors, Top Secret pads, and you can say goodbye to brake fade.

I bet ya a tank of gas Angeles crest says otherwise :wink:

I'll second that bet. Stock brakes, no matter what components you have in there, are only good for ONE hard braking zone. I'm not talking autox here... I'm talking on a road course, where you're coming down from 100-ish MPH. Stock brakes are good for autox and driving around town, but canyons and road courses NEED bigger brakes. Not just caliper/ pad/ fluid/ line upgrades, but bigger rotors.
 

Gary

Moderator
^^^^
Yup....

But Chris, if you are planning to drive your car in Owasso, Ok, I think caliper/ pad/ fluid/ line upgrades will be your first step.
 

Griffin

New member
Darth Boost":12t2pluq said:
Griffin":12t2pluq said:
roo":12t2pluq said:
Slotted or cross-driled rotors, Top Secret pads, and you can say goodbye to brake fade.

I bet ya a tank of gas Angeles crest says otherwise :wink:

I'll second that bet. Stock brakes, no matter what components you have in there, are only good for ONE hard braking zone. I'm not talking autox here... I'm talking on a road course, where you're coming down from 100-ish MPH. Stock brakes are good for autox and driving around town, but canyons and road courses NEED bigger brakes. Not just caliper/ pad/ fluid/ line upgrades, but bigger rotors.

we see eye to eye on a lot of stuff :) Too late for me to appologize for that whole pissing match over the typo deal? :D
 

SBCelicaGT

New member
There’s a lot of assumptions and guessing going on in this thread. First let’s define each function of each brake part:

Caliper: Transfers hydraulic force from the master cylinder to the brake pads. Braking torque is defined by the distance the caliper is from the center of the rotor, and by the force applied.
Brake Pads: Uses friction to turn rotational energy into heat.
Brake Rotors: Giant heat sink that dissipates heat generated from the pad/rotor contact

More terms defined at Stoptech’s website:

http://www.stoptech.com/whitepapers/glo ... ry_all.htm

And take a look at their brake bedding FAQ:

http://www.stoptech.com/whitepapers/bedinfaq.htm


There are 3 different kinds of brake fade:

1) Green fade. Means you did not properly bed the pads and the pads are gassing-out. Usually an issue for street pads; Race pads don’t have this issue.
2) Brake fluid boiling causing a mushy pedal.
3) Overheating the brake pad material that has been transferred to the rotor causing a slippery surface.

#2 and #3 are exactly why it’s important to purchase parts that meet your driving style.

It is extremely important to properly bed the pads and establish a layer of brake pad material onto the rotors. It’s this new surface that contacts the brake pads and keeps from having a “warped” rotor effect.

So what does this mean for the ST185? Do the ST185 brakes need more torque or more heat capacity? For those that drive hard and are experiencing brake fade, do you know why?

Granted my GT weighs about 400lbs less than an Alltrac so I have less mass to stop, but it really is amazing the difference a set of brake pads make.

I had run my 90 GT at Buttonwillow last October in NASA’s HPDE. The complete system was stock except for some cheap performance brake fluid (Valvoline synthetic), and some custom brake ducting for the front.

Towards the end of the 20 minute runs I noticed the brakes going a bit soft. I firmly believe this had to do with the overheating of the pad, and possibly boiling of the brake fluid.

Last month I ran in another NASA HPDE event but this time had a few changes. Namely I upgraded the rear drums to 92/93 spec disc brakes with Axxis Metalmaster pads, and on the front was using Hawk Black club race pads. The initial bite on these pads are incredible! Track temps were close to 90 degrees and without the brake ducting this time, and some ATE Superblue DOT 5 fluid, I did not have one bit of brake fade. In fact, at this point, my brakes out power my tires and really do not need to upgrade my braking system any more. The only changes I need to finish are the 92/93 spec rotors and calipers, and my SS braided brake hoses installation(something about 15 year old hoses on a race track does not rub me the right way). I got the parts; I just need to find a weekend to put them on.

Until I upgrade to race tires (RA-1, A032R, etc), I will not need to upgrade my pads any further. The brake torque is fine, and I see no need to change to a larger caliper, or larger rotors.

It’s easy to just throw parts at your car because somebody said it worked on another car. Bigger is not always better. And for cryin’ out loud, do not buy cross drilled rotors!
 

Griffin

New member
Please consider:

I have slotted factory rotors, stainless steel lines, porterfield R4S pads, and I run Motul RBF 600 (freshly flushed). I have 235/40/17 A032R H compound tires mounted on SSR Competition rims (very light combo). My pads were bedded properly and are in excellent condition - I have no brake vibration at all and normal brake performance is excellent. BUT - under LONG periods of heavy braking (Angeles crest is about a 35-40 minute run of pure twisty happiness) I start to get some fade as heat builds up. The process is consistent and repeatable. My brake hardware is all new as of like 4000 miles ago and operating at peak efficiency. BUT - its just not enough brake for a long canyon run. Ducting would probably help but I don't have the free space under car for it. This is not an autocross event - we're talking 90 mph top speeds and some braking to as low as 25 mph on certain corner entries. Depending on where you are and the direction you are running the process can be almost 100% downhill for about a 30 minute stretch. I know my fluid isn't boiling, and I know my pads aren't having offgassing problems (slotted rotors). I also know my bed in was flawless.

So while I respect what you have learned at the track days please realize that some conditions are VERY different and really DO require a system with greater capacity. The alltrac is a heavy car and it has a 60/40 weight distribution which, especially on the downhill, places a LOT of load on the front brakes. Even with what you consider a "properly sized" braking system, you run into problems after a while. Under these conditions a "overkill" system is exactly what is called for - something that can dissipate so much heat that even with continuous use under severe conditions it can continue to function at peak efficiency.
 

SBCelicaGT

New member
Griffin":dfiae7zp said:
Please consider:

I have slotted factory rotors, stainless steel lines, porterfield R4S pads, and I run Motul RBF 600 (freshly flushed). I have 235/40/17 A032R H compound tires mounted on SSR Competition rims (very light combo). My pads were bedded properly and are in excellent condition -

Point taken. A032R tires are quite heavy actually, though your wheels might be light.

I have no brake vibration at all and normal brake performance is excellent. BUT - under LONG periods of heavy braking (Angeles crest is about a 35-40 minute run of pure twisty happiness) I start to get some fade as heat builds up.

Is this all downhill so are you constantly dragging your brakes? If you find yourself "racing" on the street like this, maybe you ought to swap out your pads for race pads. Try a set of Hawk Blue pads. A set of pads is cheaper than $1000 brake system upgrade.

The process is consistent and repeatable. My brake hardware is all new as of like 4000 miles ago and operating at peak efficiency. BUT - its just not enough brake for a long canyon run. Ducting would probably help but I don't have the free space under car for it. This is not an autocross event - we're talking 90 mph top speeds and some braking to as low as 25 mph on certain corner entries. Depending on where you are and the direction you are running the process can be almost 100% downhill for about a 30 minute stretch. I know my fluid isn't boiling, and I know my pads aren't having offgassing problems (slotted rotors). I also know my bed in was flawless.

Autocrossing is for pussies. :evil: :D

90 is pretty quick, but not THAT fast, and yes I see that you mentioned there was a lot of downhill driving. A bit too fast for the street, but I won't clutter this thread with that soapbox rant.

If you are indeed overheating your pads, which it sounds like, your options are:

1)better pads
2)better thermal capacity(thicker rotors)
3)better cooling.

Ideally, there would be OEM rotors and calipers that bolt up to our cars that utilize a thicker rotor for better thermal capacity and still allow the use of 15" wheels. Something like that would be as cheap as going to the local parts store. Unless you having trouble putting your foot down, you have no need for larger diameter rotors, but hey, it's all about marketing. Thicker rotors aren't quite as stylish as those swiss cheesed 12" monster rotors.

So while I respect what you have learned at the track days please realize that some conditions are VERY different and really DO require a system with greater capacity. The alltrac is a heavy car and it has a 60/40 weight distribution which, especially on the downhill, places a LOT of load on the front brakes.

Weight distribution has much less to do with the load on the front brakes than you think. At speed, the car's momentum is the predominant factor in brake loading. And considering the fact that the ST185 is a heavy car, I can appreciate your need for larger brakes.

Even with what you consider a "properly sized" braking system, you run into problems after a while. Under these conditions a "overkill" system is exactly what is called for - something that can dissipate so much heat that even with continuous use under severe conditions it can continue to function at peak efficiency.


To each his own. I just can't justify spending $1000 when I can solve brake fade with $120 race pads and some good brake fluid.
 

AWDios

New member
On the note of the rotors being a heat sink (and I know this can cause much debate, and I'm not even saying it's how I feel) but I was told by someone who races quite regularly, that he thinks just sticking to a rotor with no cross drilling or slots is better, because other wise you are taking away mass that can be used to take in the heat. Plus you'll wear your pads faster, and unless they are forged with the holes in them, cross drilled rotors are much more fragile.

Like I said, I don't know that I entirely agree with this theory but it is something to think about.
 

SBCelicaGT

New member
Read this:

http://forums.corner-carvers.com/showthread.php?t=2002

Corner Carvers is basically a group of asshole arrogant racing pricks. But they know their shit. There's a lot of good info in that thread amidst the insults.

Also, here is a "cliff's note" version that was a response I made over at solaraguy.com:

----------------------------------------------------------
...
First, lets get some physics. Tell me how a heatsink with less mass will cool better? You do realize that a brake rotor acts as a large heatsink to transfer heat from the brake pads to the rotor. The heat generated from pads has to go somewhere and so it transfers to the rotor and caliper.

Porsche claims: "Discs are cross-drilled to enhance braking in the wet. The brakes respond faster because the water vapour pressure that builds up during braking can be released more easily."

They have said nothing about enhancing normal braking circumstances and the larger diameter rotors probably make up for the lack of material present in a smaller cross drilled rotor.

From Wilwood's website:
Q: Why are some rotors drilled or slotted?
A: Rotors are drilled to reduce rotating weight, an issue near and dear to racers searching for ways to minimize unsprung weight. Drilling diminishes a rotor's durability and cooling capacity.

Slots or grooves in rotor faces are partly a carryover from the days of asbestos pads. Asbestos and other organic pads were prone to "glazing" and the slots tended to help "scrape or de-glaze" them. Drilling and slotting rotors has become popular in street applications for their pure aesthetic value. Wilwood has a large selection of drilled and slotted rotors for a wide range of applications.

As for the porsche rotors, a few notes from a forum I frequent:
1) The holes are cast in giving a dense boundary layer-type crystalline grain structure around the hole at the microscopic level as opposed to drilling which cuts holes in the existing grain pattern leaving open endgrains, etc, just begging for cracks.

2) The holes are only 1/2 the diameter of the holes in most drilled rotors. This reduces the stress concentration factor due to hole interaction which is a function (not linear) of hole diameters and the distance between them.

3) Since the holes are only 1/2 as big they remove only 1/4 as much surface area and mass from the rotor faces as a larger hole. This does a couple of things:

It increases effective pad area compared with larger holes. The larger the pad area the cooler they will run, all else being equal. If the same amount of heat is generated over a larger surface area it will result in a lower temperature for both surfaces.

It increases the mass the rotor has to absorb heat with. If the same amount of heat is put into a rotor with a larger mass, it will result in a lower temperature.

3) The holes are placed along the vanes, actually cutting into them giving the vane a "half moon" cut along its width. You can see that here:

jagpoco.jpg


This does a couple of things:

First, it greatly increases the surface area of the vanes which allows the entire rotors to run cooler which helps prevent cracks by itself.

Second, it effectively stops cracking on that side of the hole which makes it very difficult to get "hole to hole" cracks that go all the way through the face rotor (you'll get tiny surface "spider cracks" on any rotor, blank included if you look hard enough).

That's why Porsche rotors are the only "crossdrilled" rotors I would ever consider putting on my car.

BTW, many of the above features are not present in older Porsche brakes. The above is for "Big Reds" and newer.


This is quite different from the standard drilled rotors you get from brembo/kvr/powerslot/"insert random ricer parts brand name here" brake rotors.

Further proof of the uselessness of cross drilled rotors are found here:

http://www.teamscr.com/rotors.htm

Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the 40’s and 50’s, not a whole lot. Rotors were first ‘drilled’ because early brake pad materials gave off gasses when heated to racing temperatures – a process known as ‘gassing out’. These gasses then formed a thin layer between the brake pad face and the rotor, acting as a lubricant and effectively lowering the coefficient of friction. The holes were implemented to give the gasses ‘somewhere to go’. It was an effective solution, but today’s friction materials do not exhibit the same gassing out phenomenon as the early pads.

For this reason, the holes have carried over more as a design feature than a performance feature. Contrary to popular belief they don’t lower temperatures (in fact, by removing weight from the rotor, the temperatures can actually increase a little), they create stress risers allowing the rotor to crack sooner, and make a mess of brake pads – sort of like a cheese grater rubbing against them at every stop. (Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it.)

The one glaring exception here is in the rare situation where the rotors are so oversized (look at any performance motorcycle or lighter formula car) that the rotors are drilled like Swiss cheese. While the issues of stress risers and brake pad wear are still present, drilling is used to reduce the mass of the parts in spite of these concerns. Remember – nothing comes for free. If these teams switched to non-drilled rotors, they would see lower operating temperatures and longer brake pad life – at the expense of higher weight. It’s all about trade-offs.

From Stoptech:

Which is better, slotted or drilled rotors?

StopTech provides rotors slotted, drilled or plain. For most performance applications slotted is the preferred choice. Slotting helps wipe away debris from between the pad and rotor as well as increasing the "bite" characteristics of the pad. A drilled rotor provides the same type of benefit, but is more susceptible to cracking under severe usage. Many customers prefer the look of a drilled rotor and for street and occasional light duty track use they will work fine. For more severe applications, we recommend slotted rotors.

That almost sounds like an excuse to use cross drilled rotors, and for your street car which probably is never driven on the track, the drilled rotors are fine, but as Stoptech states, they will crack and are not good for severe applications.

From Baer:

"What are the benefits to Crossdrilling, Slotting, and Zinc-Washing my rotors?

In years past, crossdrilling 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...However, with today’s race pad technology, ‘outgassing’ is no longer much of a concern...Slotted surfaces are what Baer recommends for track only use. Slotted only rotors are offered as an option for any of Baer’s offerings."

Then from Grassroots Motorsports:
"Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the '40s and 50s, not a whole lot. Rotors were first drilled because early brake pad materials gave off gasses when heated to racing temperatures, a process known as "gassing out." ...It was an effective solution, but today's friction materials do not exhibit the some gassing out phenomenon as the early pads. Contrary to popular belief, they don't lower temperatures. (In fact, by removing weight from the rotor, they can actually cause temperatures to increase a little.) These holes create stress risers that allow the rotor to crack sooner, and make a mess of brake pads--sort of like a cheese grater rubbing against them at every stop. Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it...Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows for it. Cutting thin slots across the face of the rotor can actually help to clean the face of the brake pads over time, helping to reduce the glazing often found during high-speed use which can lower the coefficient of friction. While there may still be a small concern over creating stress risers in the face of the rotor, if the slots are shallow and cut properly, the trade-off appears to be worth the risk. (Have you looked at a NASCAR rotor lately?)



And then, let's check out what was said on the aforementioned Altima thread:

Here is how it works. The friction between the pad and rotor is what causes you to stop. This friction converts your forward energy into heat (remember Einstein: Energy is neither created nor destroyed, it is converted). Now that heat is a bad thing. Yes it is bad for the rotors but it is a lot worse for the pads. A warped rotor will still stop the car - it will just feel like shit. Overheated pads however WILL NOT stop the car. It is here where the rotors secondary responsibility comes in. Its job now is to DISSIPATE the heat away from the pads and DISPERSE it through itself. Notice that DISSIPATE and DISPERSE are interchangeable? Once the heat is removed from the pad/surface area it is then removed. Notice where the removal falls on the list of duties? That's right - number 3. Here is the list again. Memorize it because I will be using it a lot in this post:

#1 Maintains a coefficient of friction with the pad to slow the forward inertia of the vehicle

#2 DISSIPATE the heat

#3 REMOVE the heat from the brake system

Let's look more in-depth at each step now shall we? No? Too bad assclown we are doing it anyway.

#1 Maintains a coefficient of friction with the pad to slow the forward inertia of the vehicle:
This one is pretty simple and self-explanatory. The rotor's surface is where the pads contact and generate friction to slow the vehicle down. Since it is this friction that causes the conversion of forward acceleration into deceleration (negative acceleration if you want) you ideally want as much as possible right? The more friction you have the better your stopping will be. This is reason #1 why BIGGER brakes are the best way to improve a vehicle's stopping ability. More surface area on the pad and the rotor = more friction = better stopping. Does that make sense Ace? Good. Let's move on.

#2 DISSIPATE The Heat:
Let's assume for a second that the vehicle in question is running with Hawk Blue pads on it. The brand doesn't really matter but that is what I am using as my example. They have an operating range of 400 degrees to 1100 degrees. Once they exceed that 1100 degree mark they fade from overheating. The pad material gets too soft to work effectively - glazing occurs. This means that a layer of crude glass forms on the surface of the pad. As we all know glass is very smooth and very hard. It doesn't have a very high coefficient of friction. This is bad - especially when I am coming down the back straight at VIR at 125MPH. Lucky for us the rotor has a job to do here as well. The rotor, by way of thermal tranfer DISSIPATES the heat throughout itself. This DISSIPATION lessens the amount of heat at the contact area because it is diluted throughout the whole rotor. The bigger the rotor the better here as well. The more metal it has the more metal the heat can be diluted into. Make sense? This isn't rocket science here d00d.

#3 REMOVE the heat from the brake system:
Now comes your favorite part of the process. This is what you thought DISSIPATION was. It is ok. I will allow you to be wrong. This is the step where the rotor takes the heat it DISSIPATED from the pads and gets rid of it for good. How does it do this? By radiating it to the surface - either the faces or inside the veins. It is here where cool air interacts with the hot metal to cool it off and remove the heat. Once again there is a reoccuring theme of "the bigger the better" here. The bigger the rotor, the more surface area it will have which means more contact with the cooling air surrounding it. Got it? Good.

Now let's look at why cross-drilling is a bad idea.

First - as we have already established, cross-drilling was never done to aid in cooling. Its purpose was to remove the worn away pad material so that the surfaces remained clean. As we all know this doesn't have much of a purpose nowadays.

Next - In terms of cooling: Yes - x-drilling does create more areas for air to go through but remember - this is step 3 on the list of tasks. Let's look at how this affects steps 1 and 2. The drilling of the rotor removes material from the unit. This removal means less surface area for generating surface friction as well as less material to accept the DISSIPATED heat that was generated by the friction. Now because of this I want to optimize step one and 2 since those are the immediate needs. If it takes longer for the rotor to get rid of the heat it is ok. You will have a straight at some point where you can rest the brakes and let your cooling ducts do their job. My PRIMARY concern is making sure that my car slows down at the end of the straight. This means that the rotor needs to have as much surface as possible to generate as much friction as possible and it needs to DISSIPATE the resulting heat AWAY from the pads as quick as possible so they continue to work. In both cases x-drilling does nothing to help the cause.

Now let's talk about strength - and how x-drilled rotors lack it. This one is simple. Explain again just how drilling away material/structure from a CAST product DOES NOT weaken it? Since you are obviously a man of great knowledge and experience surely you have seen what can happen to a x-drilled rotor on track right? Yes it can happen to a non-drilled rotor as well but the odds are in your favor when pimpin' bling-bling drilled y0! Since you are also an expert on thermodynamics why not explain to the group what happens to a cast iron molecule when it is overheated. I will give you a little hint - the covalence bonds weaken. These bonds are what hold the molecules together boys and girls. You do the math - it adds up to fractures.

So why don't race teams use them if they are so much better? Consistency? Hmmmm . . . no. I am gonna go with the real reason her chodeboy. It is because of several factors actually. They are as follows but in no particular order:

- Less usable surface area for generating friction
- Less material to DISSIPATE the heat away from the pads
- Less reliable and they are a safety risk because of fatigue and stress resulting from the reduced material

And what are the benefits? Removal of particulate matter and enhanced heat removal. I gotta tell ya - it is a tough choice but I think I am going to stick with the safe, reliable, effective-for-my-stopping needs solution Tex.

Thank you, please drive through.
----------------------------------------------------


Slotted rotors can have some benefits, but personally I'll stick with my $20 uncut Brembos that stop just fine.
 

AWDios

New member
Yeah, that all makes sense. It seems like slotted has it's negatives and positives. Personally I think the positives outweigh the negatives so I'll probably go that way.
 

SBCelicaGT

New member
Slotted rotors are just expensive(initial cost and due to the fact that they can't be turned). If Brembo supplied slotted rotors at a cost close to their full face rotors, I'd probably pick up a set. Presently I am using a separate set of rotors and pads for the track versus the street and can't see purchasing 8 slotted rotors any time soon. :lol:
 

Griffin

New member
SBCelicaGT":1lg6k8c2 said:
To each his own. I just can't justify spending $1000 when I can solve brake fade with $120 race pads and some good brake fluid.

Ummm - RBF600 is about as good as brake fluid gets... As for pads - anything more agressive than what I have is going to be very rotor - unfriendly. Yes it will get the job done but I'll be looking at picking up a new set of rotors with my next set of pads in that case. And it won't be that far off....

The reasons I like the idea of larger brakes is they should give the increased performance I want while at the same time maintiaining some kind of reasonable reliablity
 
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