There are a lot of repetitive questions about brakes. I don’t see a Sticky for a Brake FAQ so I'll try and start one, maybe it will reduce some of the repetitive questions. I wrote the Brake FAQ for the Acura ClubRSX website, so I lifted it and tried to modify the vehicle specific information to reflect the RX8. Feel free to add to or correct factual errors, particularly vehicle specific ones I may have missed. Inevitably there are some areas that will be open to discussion but I've tried to cover the basics. When I get more info I'll add to it this was just a first try.

Brakes general description
The RX8 comes with either of 2 OEM brake systems. All models have ventilated front and rear disc brakes with ABS. The base AT model has 11.9 in. (303 mm) diameter front discs while the AT with sport suspension and all MT have larger 12.7 in. (323 mm) diameter front discs. Both models have the same 11.9 in. (302 mm) diameter ventilated rear discs and floating calipers. The larger front brakes have a different front caliper, master cylinder, and rear proportioning valve than the base AT model. Both models use single piston, cast iron, floating calipers front and rear.

The braking system is designed to stop the wheels of the car. Both the base AT model and the MT braking systems are fully capable of stopping the wheels of the car in excess of 60 mph multiple times in sequence. This is an important point. Because the brakes are fully capable of stopping the wheels at speeds likely to be encountered on the street, the limiting factor in how quickly you can stop your car is dependent primarily on your tires and road conditions (i.e. wet or dirt). If you truly want to stop your car in a shorter distance, buy stickier tires. This can be accomplished by buying tires with stickier rubber (generally lower treadwear rating), better construction, or wider footprints (most common). That said there are several areas where the OEM brakes can be modified to fit specific conditions and these are discussed below.

ABS
The Anti-lock Braking System is designed to prevent locking up of the wheels during hard or panic braking. A locked-up sliding wheel has a lower coefficient of friction with the road that a rolling wheel, so braking distances are shortened if the wheels can be slowed quickly without locking up. Furthermore, you can’t steer a locked-up sliding wheel, so ABS has the added benefit of allowing directional control during panic braking. The ABS system consists of wheel sensors that monitor wheel rotation, a computer that decides when the braking system should be modulated, and a hydraulic pump that actuates the brakes during ABS operation. All of this happens multiple times a second. If you set off the ABS on a wet or sandy road you will feel a vibrating "bbrrrrppp" in the brake pedal.

Brake fluid
The RX8 comes with a DOT3 recommended brake fluid like just about every car currently available. DOT3, DOT4, and DOT5.1 brake fluids are glycol ether based hydraulic fluids that by their chemical nature are hydroscopic, meaning they will absorb water. DOT5 is a silicon based brake fluid and is not compatible with the other fluids, once you use it you cannot return to the other fluids and should not be used. Water dissolved in the brake fluid does 2 things, both of them bad. It accelerates rust and corrosion of the internal parts in the master cylinder and caliper pistons. Worse, the boiling point of fresh brake fluid is significantly lowered by small concentrations of dissolved water in the fluid. For this reason, when comparing boiling points of brake fluid for a daily driver, the wet boiling point is probably the most important.

People who regularly stress their brakes due to carrying heavy loads (not usual with an RX8) or braking at high speeds (more common in an RX8) should, at the very least, replace their brake fluid annually with fresh fluid to keep their brake fluid boiling points near the dry point. If you are going to track your car either on an autocross track, or more importantly on a road course, the first modification you should make is to put fresh brake fluid in your RX8. Many people will at this point select a racing brake fluid with a higher wet and dry boiling point such as ATE Super Blue or Motul 600 racing brake fluid among others. The ATE Super Blue also comes in gold which is the same stuff without the dye, useful if you alternate colors so you know when the flushing is done.

For more info on brake fluid see http://www.stoptech.com/tech_info/wp_brakefluid_1a.shtml
This table of Brake fluid information is from Scott Barton's website
http://i202.photobucket.com/albums/aa243/justjim13/brakefluidcrop.jpg
*The wet boiling point is the more important number to consider unless you flush frequently.

Brake Fade
There are 3 types of brake fade commonly encountered.
Green fade. This type of fade only happens with brand new unbedded pads. Pad compounds with organic binders will offgass as the binders volatilize when they are heated for the first time. These gasses produce a thin boundary layer on the pad surface which prevents or interferes with the proper friction of the pad on the rotor. Once the pads have been thoroughly heated the gasses are no longer produced and the problem goes away. As a result, your first braking application on brand new pads should not be a panic stop from 90 mph. All brake pads should be bedded in, more on that later.
Pad fade
Every pad compound, street or track has a range of operating temperature. Above that range the coefficient of friction will drop and the ability of the pad to stop the rotor will diminish. Multiple stops from high speed such as on a road course, or a fast descent down a twisty mountain road can over heat the brakes and exceed the operating range of the pads and the brakes will start to fade. The pedal will still feel hard and firm but the car doesn’t slow down like it used to. The cure is let the brakes cool off, and if the pads haven’t been incinerated they will resume working when temperatures cool down.
Fluid fade
This is the MacDaddy of fade and should be avoided (see wet and dry boiling points of brake fluid above). If the brakes get hot enough, the fluid in the caliper can exceed the boiling point of the fluid, especially if the fluid has absorbed water. Hydraulic systems depend on the physical principal of the incompressibility of fluids. When the fluid boils, bubbles of gas enter the hydraulic system, and unlike fluids, gasses are compressible. When you push on the brake pedal, all you are doing is squishing bubbles, not moving pistons. As a result, the brake pedal goes to the floor, the car goes where you don’t want it, and small wimpering sounds emanate from the driver as he/she looks for something soft to hit. The cure requires bleeding the brakes as the bubbles will not completely resorb on their own. Most people who track their car bleed their brakes before an event to have dry fluid and sometimes after an event to remove any bubbles.

Brake Pads
As mentioned above, the OEM brake pads are fully capable of setting off the ABS at high speeds, even with R-compound tires. They will do this multiple times. However, they won’t do it indefinitely. After 5 or 6 panic stops from 60mph they will begin to fade from overheating. Frequent hard braking with OEM pads may lead to pad deposits on the rotor which gives a pulsating pedal. For those who have encountered pad deposits (more on this later) or those who regularly autocross or track their car on road courses, an upgraded performance pad may increase the operating temperature range and prevent pad deposits and pad fade.

Brake pads generally fall in 3 categories – OEM, street performance, or track only. If all you ever do is drive to work, hit the interstate, and occasionally goose it at the traffic light, all you need are OEM pads. If you live in a mountainous area and like to drive fast, or you are continually exploring the limits of ABS on the off ramp, or you compete in autocrosses, you may benefit from a street performance brake pad. If you are tracking your car on road courses more than once (beyond the novice category), even a street performance pad may put pad deposits on your rotors and may fade. For experienced drivers on road courses, dedicated track pads will provide the best performance. Why not use track pads on the street, you may ask? Because, 1. They are expensive; 2. Some track pads need to be warmed up before they grab (although some modern formulas work relatively well when cold); 3. They are hard on the rotors; 4. They are very dusty; 5. The pad dust can be corrosive to wheels and body paint; 6. They tend to be noisy as well.

Some popular street performance pads for the RX8 include but are not limited to:
Axxis Ultimates
Hawk HP plus
Brembo Sport
Ferodo DS2500
Carbotech Bobcat
Cobalt GT Sport

Some popular dedicated track pads for the RX8 include but are not limited to:
Hawk HT10, DTC60
Carbotech XP10/XP8
Cobalt XR2/XR5

Track pad manufacturers often recommend using a slightly less aggressive compound in the rear such as Carbotech XP8 or Cobalt XR5.

Performance street pads and track pads generally have higher coefficients of friction (mu) as compared to OEM in addition to higher operating temperature ranges. This may give a better feel to the brake pedal but will not measurably shorten stopping distances. The benefits of performance street and track pads are in resistance to brake fade, which is incurred due to multiple hard stops such as encountered on road courses. The OEM brakes on the RX8 are superb and many people successfully track and race the RX8 with only a fluid and pad upgrade.

This table of brake pad information is from Scott Barton's website
http://i202.photobucket.com/albums/aa243/justjim13/brakepadscrop.jpg

Pad Bedding In
Most companies will include proper bedding technique in the instructions, and they more or less follow a similar procedure. As soon as the brake pads are installed, proceed to do some low speed braking, typically from 40mph to a slow roll to bring the brakes up to normal operating temperatures. Find yourself a place where you can do uninterupted sequential hard braking events. Do a set of 4 to 5, 70mph to 20mph, hard braking events followed by a 10-15 minute rolling cool down period. All of this is done Without coming to a complete stop. Braking should be hard but not hard enough to lock the wheels or set off the ABS. The brakes should be brought up to the upper thermal range of the pads. Bedding in the pads correctly does a few things: 1. Gets rid of green fade caused by outgassing of organic binders in the pad; 2. The primary purpose of bedding pads is to lay down an even layer of pad material on the rotor face to facilitate adherent friction. Everybody should find a place where there is a stretch of road with little or no traffic that they can safely get up to at least 60mph and do the above procedures including a 10 minute cooldown period afterwards WITHOUT COMING TO A COMPLETE STOP.

The Myth of Warped Rotors
Many people comment that they need to replace their entire brake setup because their rotors are "warped". While it may be possible (usually in an alternate universe) to warp a rotor it is exceedingly rare. Rotors may wear thin, they may crack, they may rust, but they rarely if ever warp. People think their rotors are warped for several reasons.
1. The pedal pulses and it “feels” like the rotor is “warped”.
2. Their mechanic told them its warped.
3. Their machinist told them its warped.
4. Their beer buddy, who knows all, told them its warped.
5. Their dad told them its warped.

The myth is perpetuated for several reasons. It sounds plausible, you can measure it, and the cure for a warped rotor fixes the problem that led to the belief that the rotor was warped, therefore it must have been warped. Not so, what is really happening was alluded to above in the brake pad discussion.

Brake pads rely on 2 types of friction, abrasive friction and adherent friction. Abrasive friction is just what it sounds like. Modern brake pads, particularly performance and track pads, rely heavily on a thing called adherent friction to fully develop their coefficient of friction. Adherent friction is more like the friction of sticky glue to something, a molecular bond that forms and breaks causing friction. Modern brake pads lay down a even layer of pad material on the rotor face during bedding and normal use. This layer of pad material on the rotor sticks to the pad material on the pad and voila increased friction. If the brake temperature exceeds the pads operating range this nice even layer starts to melt and becomes an uneven splotchy layer of material. This now variable thickness of glue stuck to the rotor causes the pulsations in the pedal as the pad follows the uneven pad deposits around the rotor face.

There are basically 2 ways to get rid of pad deposits. One is to machine them off. This is why the machinist and the mechanic (and for that matter, probably your dad and beer buddy) think the rotor is warped. The machinist measures the rotor as being warped when really he is measuring glue stuck to the rotor face. Machining the face of the rotor removes the glue and incorrectly confirms what he thought was the cause. The other way is to rebed the brakes, preferably with new pads of a higher temp range and coefficient of friction. Bedding (or rebedding because it can be repeated) brake pads is the controlled process of laying down an even layer of new pad material. If the new pads have a higher temperature range, you can melt off the old while you are laying on the new. This generally involves 5 or 6 hard braking events from 70 to 20 mph without stopping in rapid succession. Sometimes it may need to be repeated for another 5 events after cooling without stopping. I once had pad deposits after a track event on performance street pads that were so bad I stopped the car twice on the highway to check for broken suspension and brake parts. I cured the pad deposits with a new set of pads and a double bedding procedure.

Rotors are made of cast iron for a reason. It is tough stuff and is the best alloy in terms of heat resistance, ductility, strength, and hardness. All rotors, even the inexpensive ones, are made of similar cast iron alloys as the expensive racing rotors with the exception of carbon rotors found only on the highest end racing cars such as Formula 1 and a few others.

For further information on this subject see Carroll Smith
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

Slotted and drilled rotors
Many people while trying to replace what they think are warped rotors, or while trying to make their car stop better, inquire about which is better, drilled or slotted rotors. The answer is neither. Neither holes nor slots will stop your car any quicker. Once you've gotten past green fade in the first heat cycle of new pads described above, outgassing is no longer a significant issue and holes and slots won't stop you any better. Holes and slot don't cool the rotors any better either. Furthermore, drilled rotors are generally to be avoided as the holes act as stress risers increasing the likelyhood of cracking. Slots won't hurt anything but your wallet but they won't help anything either except looks. If all you want is bling get the slots.

One structural aspect that will improve a rotors heat dissipation is curved internal vanes. The OEM rotor and most aftermarket rotors are straight vaned rotors. Curved vanes pump more air like a water pump. Racing Brake makes OEM sized rotors for the RX8 that are curved vanes. Another structural aspect that improves rotor design is 2-piece floating hat rotors. These rotors have a separate center hat, usually of aluminum alloy, that bolts to a cast iron ventilated rotor ring. These rotors have superior ventilation and the aluminum hat wicks away some of the heat, and they have less unsprung and rotational weight. Many aftermarket Big Brake Kits come with 2-piece floating hat rotors. Most competitive racing cars have 2-piece floating hat ventilated rotors.

OEM sized 2-piece floating hat rotors for the RX8 include but are not limited to:
DBA5000 www.dba.com
Racing Brake www.racingbrake.com

Big Brake Kits
Many people, in an effort to improve their cars decide to purchase an aftermarket brake system commonly referred to as a Big Brake Kit or BBK. As the term suggests the brakes are “bigger” than OEM. The implication is that bigger is better. Like much in life it is more complex than that. As mentioned above, the OEM brakes of both the AT model and the MT are fully capable of setting off the ABS under multiple panic stops. So if a brake system is already capable of locking up the wheel (even under racing conditions) how will a bigger braking system stop the car any shorter. The short answer is it won’t. BBKs don’t stop the car shorter or quicker. The advantage of a BBK is in the B as in bigger. A bigger rotor dissipates heat faster and better. So a well designed BBK will dump heat better. This is only an advantage if your brakes are overheating. Many of us race and track successfully without fade with OEM brakes with just better pads. If you are tracking the car with dedicated track pads and you are operating at the upper limit of your pads operating range you may benefit from a BBK. Better BBKs also utilize a 2-piece rotor which also has less unsprung and rotational weight.

Some people want a BBK for looks which is OK but buyer beware. Braking systems are all about balance, balance between the front and the rear. If a BBK is not well designed, and is just something available off the shelf that happens to fit, the front to rear brake bias or balance will be upset and the stopping distance with your very cool looking BBK will be longer, not shorter than your girlfriend with the stock OEM AT model on cheap tires.

The RX8 has a nearly 50/50 front/rear weight bias. Despite the RX8s excellent balance, the front brakes do more of the work than the rears due to weight shift under deceleration. Mazda engineers spent a lot of time matching piston diameters of the front and rear calipers and the master cylinder to get a balanced front/rear brake bias. Additionally, most cars including the RX8, have a proportioning valve between the front and rear which limits or modifies the maximum hydraulic pressure to the rear under heavy braking. This is necessary because of the forward weight shift under heavy braking. The proportioning valve prevents the rear wheels from prematurely activating the ABS and disrupting maximum braking efficiency.

Premature activation of the front or rear ABS is an important point to consider when making brake system modifications, such as adding a BBK. If the front caliper in the BBK you select is too big the front will activate the ABS prematurely. Since the front does most of the work you just turned off most of your brakes. If the front caliper is too small, it will allow the rear to activate prematurely. In either case once one end of the ABS goes off, further pedal pressure won't help and your stopping distances will increase instead of decrease. Bigger is not better if it upsets the balance of the braking system.

Some BBKs for the RX8 include but are not limited to:
Racing Brake www.racingbrake.com
StopTech www.stoptech.com

For more info on this subject see http://www.stoptech.com/tech_info/wp_brakebiasandperformance.shtml

Comments?

great post,

lots of info. shocked that after my couple of day absence that no one has made a comment..

nice to see the importance of bedding in mentioned.

beers :beer:

Great info jim, thanks.

I'm looking for pads (maybe rotors) replacement and didnt understand much about it. Lots of info well explained in the same post makes it so much clearer!

Now, I still need to take the car to the dealer to figure out what parts exactly need to be changed but I was already told that its recommanded to get new rotors as well because they will probably get too think when installing the pads.

How can I figure out for sure whether I really need to change the rotors or not?

at the same time, maybe you can recommand a set of pads : I'm hesitating between Mazdaspeed pads and Hawk Blue or Hawk HP+ or HPS or even Brembo?

whoa, this is an awesome thread. Now I can just send people here when they ask me brake questions. :)

whoa, this is an awesome thread. Now I can just send people here when they ask me brake questions. :)

meanwhile, you can already answer all my questions! :)

great post.... now some mod needs to make it a sticky

Great info jim, thanks.

I'm looking for pads (maybe rotors) replacement and didnt understand much about it. Lots of info well explained in the same post makes it so much clearer!

Now, I still need to take the car to the dealer to figure out what parts exactly need to be changed but I was already told that its recommanded to get new rotors as well because they will probably get too think when installing the pads.

How can I figure out for sure whether I really need to change the rotors or not?

at the same time, maybe you can recommand a set of pads : I'm hesitating between Mazdaspeed pads and Hawk Blue or Hawk HP+ or HPS or even Brembo?

The only reason to replace the rotors is if they are below the minimum thickness (22mm front 16mm rear) which takes a lot of miles or badly scored (which is unlikely unless you track the car on road courses with racing pads). You will need to remove the rotor to actually measure the thickness accurately with a micrometer. For what its worth I put 90,000 miles and 8 track days on the rotors on the front of my FWD Acura (which is a lot harder on brakes than the RX8) before they wore too thin. Some shops will insist on selling you new rotors because A. they make money and B. they know the pads are starting on a fresh surface so they don't need to worry about previous pad deposits causing pulsations and taking the time to explain the pad bedding process. Really, when was the last time you had a brake job that came with a discussion of pad bedding, uneven pad deposits, pad thermal ranges, and adherent versus abrasive friction coefficients?

If you are not tracking the car, and use it as a daily driver with only the occaisional spirited driving expected with a sports car, really the OEM pads are probably your best bet as the RX8 has superb OEM brakes. If you have encountered uneven pad deposits due to your "driving style" or are determined to have a higher thermal range pad, the Hawk HP plus is one possibility. Don't get the Hawk Blues, they are old technology and very hard on rotors for their temp range. I've never used the Mazda Speed pads but they are probably another good choice. I have experience with the Axxis Ultimates and they are a good pad. There are others, Carbotech Bobcats, Carbotech AX6, Cobalt GT sports as well. One general rule of thumb, As the pad thermal range increases so does the brake dust. Most if not all of the pads I just mentioned will dust your wheels more than the OEM.

Thanks very much for the post! It definitely answers some of the questions I have about changing out my rotors for slotted and if it was worth it. Looks like I'll stick to OEM when they actually do need changing.

I was wondering if you could comment on ceramic brake pads. I've heard good things about the Hawk ceramics and wanted to get some opinions on their effectiveness with OEM rotors.

I would like similar to better pads (when compared against OEM) and less brake dust without sacrificing much, if anything. I'm also guessing that the thermal range of ceramics is higher than the OEM brake pads? This would lead me to believe that as long as there was enough rotor thickness left that it would be okay to put them on and bed in to the rotors.

Once again, thanks for your help!

Thanks very much for the post! It definitely answers some of the questions I have about changing out my rotors for slotted and if it was worth it. Looks like I'll stick to OEM when they actually do need changing.

I was wondering if you could comment on ceramic brake pads. I've heard good things about the Hawk ceramics and wanted to get some opinions on their effectiveness with OEM rotors.

I would like similar to better pads (when compared against OEM) and less brake dust without sacrificing much, if anything. I'm also guessing that the thermal range of ceramics is higher than the OEM brake pads? This would lead me to believe that as long as there was enough rotor thickness left that it would be okay to put them on and bed in to the rotors.

Once again, thanks for your help!

"Ceramics" in brake pads is a bit of a marketing hype. Many brake pads have some ceramic compounds in the complex mixtures of various compounds that make up brake pads. As a result just about any brake pad company can make the claim that they have a ceramic pad. Ceramic compounds include a group of compounds, not just a single one, that can be added to modify the friction coefficient, thermal range, and quantity and color of dust. Supposedly, you could have a pad with good thermal stability, good bite, and light colored dust. Ceramic fibers are there to replace some of the metallic or orgainic fibers that reinforce the pad material although they don't replace all of it. I'm pretty sure the OEM has some ceramic in it. However, both the street performance pads I used on my previous car as well as my track pads are carbon kevlar ceramics and they dust like a mofo and will squeal Beethoven's fifth symphony if you don't shim and grease their backs, and the track pads will damage my wheels and even paint if I don't clean off the dust.

Brake pad composition is a bit of black art as well as chemical science and engineering. Trying to get a pad that grabs consistently at -20F and 1600F, is quiet, relatively non-toxic, non-corrosive, easy on the rotors, and inexpensive is a bit of the holy grail. Pads are generally made up of fillers, binders, reinforcing fibers, and lubricants. Reinforcing fibers provide mechanical strength to the friction material and include, metals, kevlar, glass, and ceramic fibers, and formerly asbestos. Just some of the ingredients off the top of my mind in various pads not in any particular order: carbon/graphite, limestone, ceramic compounds (various metal oxides), iron, copper, brass, aluminum, zinc, glass, kevlar, epoxy, phenolic, and slicone resins, clay, silicates, proprietary compounds (secret), rubber, even cork and cashew dust.

Very nice response justjim. Definitely parts art & science. I sure do miss asbestos in brake pads. They rarely squealed.

I liked the "while it may be possible (usually in an alternate universe) to warp a rotor" and they told me it was warped part. :lol:

The Myth of Warped Rotors
[snip]
The myth is perpetuated for several reasons. It sounds plausible, you can measure it, ...

If you can measure it, how can it be a myth? I've had warped rotors. I've measured the lateral run-out. Just resurfacing the rotor, without turning, did nothing. Replacing or turning the rotors fixed it.

It's usually caused by someone not tightening the lug nuts in the right sequence. I've learned to loosen and re-torque lug nuts after a yahoo at an inspection station does his thing with an air wrench.

Other than that, really great FAQ.

Ken

great read and top notch info. glad i read this before spending any money on my brakes...they should be good for a while, planning to service them this weekend, maybe ill flush the fluid too....im just so lazy. lol

If you can measure it, how can it be a myth? I've had warped rotors. I've measured the lateral run-out. Just resurfacing the rotor, without turning, did nothing. Replacing or turning the rotors fixed it.

It's usually caused by someone not tightening the lug nuts in the right sequence. I've learned to loosen and re-torque lug nuts after a yahoo at an inspection station does his thing with an air wrench.

Other than that, really great FAQ.

Ken

Well you have to be careful of exactly what you are measuring. The usual scenario is customer comes in with pulsating brake pedal. Mechanic dutifully checks or remembers the service manual recomendation to check for lateral runout, puts a gage on the rotor while its on the car and watches the needle dance around and exceed the minimum runout spec and yells over to the customer service manager and says "He's got a warped rotor and it needs to be turned". Client dutifully pays for rotor machining and "voila" no more pulsing pedal. The mechanic is happy, the customer is happy, albeit poorer, and the customer service manager is happy. And everybody believes that the rotor was warped and they foster this myth for future clients. But the rotor is likely not warped.

If the client has exceeded the thermal range of their brake pads, the pads will lay down a lumpy uneven layer of melted pad material. It is this material, as opposed to warped rotor material, that is likely what you or your mechanic measured. You can scrape it off with a lathe or you can rebed the pads if they are not too incinerated. Rebedding with new pads of a higher temp range will melt and scrape the old mess off the rotor and lay down an new even layer and the formerly "warped" rotor will be as good as new.

If you don't believe me check with Carroll Smith the author of "Tune to Win" and Drive to Win" and many other well known books and who has considerably more experience than me at http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
I've confirmed just about everything he says on the track with my own vehicles.

higher trim level AT's have the bigger rotors up front i believe...
maybe i'm wrong lol..

...If you don't believe me check with Carroll Smith the author of "Tune to Win" and Drive to Win" and many other well known books and who has considerably more experience than me at http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
I've confirmed just about everything he says on the track with my own vehicles.

No question that Smith knows his stuff. But he's talking about disks that are properly mounted and torqued. Out in the world of daily drivers where you don't have control over who mounts wheels, rotors do get warped from improper tightening.

Wandering down nostalgia lane... I never bought any of Smith's books, but his first one started out as a series of articles in Sports Car Graphic. I remember devouring those articles. They stressed an approach and attitude that went well beyond race cars.

Ken

How much do the 12.7" rotors weigh?

On Racingbrakes website it states that:

Weight Comparison
One-piece 18.5 lbs.
Two-piece 14.1 lbs.

and thats for the stock size


thecow135: you are correct... the sport and GT models on the AT's have the same suspension/brakes as the MT's

I tried to go back and correct the brake size for the AT sport but I'm at the word size limit for a single post so I can't add to it:eek:. Good catch on the AT brake size info.

Great info about the brakes! All I can say is that the Porterfield R4's are the best pads I've ever used as a spirited DD/track car pad

I recently went to have my brakes checked and the manager stated I needed new rotors. Six months ago I had my brakes checked and was told my pads were fine with 60% pads still left. Less than six months go by and less than 5000 miles later I need new rotors. Not only that but I was to be charged $800 becuse I had a sport tuned suspension and needed special "KUKI" rotors. I thought this was stanrge when I went to the dealer and he said my rotors were fine I just needed new pads and they needed to be machined. Again, another $500 . Is this accurate or is someone about to make some money off me. Not a total mechanical idiot but I do realize when people are trying to bend me over. Any opinion would be greatly appreciated.

I tried to go back and correct the brake size for the AT sport but I'm at the word size limit for a single post so I can't add to it:eek:. Good catch on the AT brake size info.

Great info post Jim. It should definitely be a sticky.

Be nice if the Cobalt pads were included in the chart. I know you included them in some examples of common pads for the track but most people are going to overlook that. And their numbers are significantly different from almost every other manufacturer. I'd also like more info from Cobalt on why they state that their pads do not need to be bedded in. I can dig up the post in the comp forum with a statement from Cobalt regarding their process if it helps.

You may also want to include the benefits of cleaning a rotor between pad swaps with brake cleaner especially when swapping different brands of pads and links to DIYs for bleeding brakes, changing pads, changing brake lines, and changing rotors.

Oh and the benefits and problems of going to stainless brake lines along with a link to that DIY.

Jim - here's the post I was referring to with a lot of good brake info/graphs that could probably make it into your post.

http://www.rx8club.com/showthread.php?t=137786

And here's the post from Cobalt Friction regarding their lack of bedding requirements:

http://forums.corvetteforum.com/1560497854-post9.html

Cobalt Friction XR-Series Brake Pads

--------------------------------------------------------------------------------
The Cobalt XR-Series Carbon-Ceramic brake pads are based on hybrid sintermetal technology coupled with secondary carbon precursor deposition, making them unlike any other brake pad on the market. The XR-Series is the result of considerable R&D, taking from what we have learned over the years working with race teams in Grand Am Rolex & Cup, World Challenge, and SCCA club racing. The benefits of the new materials are:

(1) much broader temperature range (50F min)
(2) zero-bedding
(3) excellent disc finish and pad wear rates
(4) unsurpassed consistency

The XR-Series materials are resinless and thus do not require outgassing or traditional bedding, providing true "out of the box" race performance. This performance attribute had been supported by/with numerous teams in Grand Am and World Challenge starting races with new discs and pads. Reference teams include Blackforest Motorsports (Grand Am Mustangs in GS and GT classes) and LG Motorsports (World Challenge GT Corvettes), as well as factory supported GM race programs in various series. Resin-based materials, which include all pads from the major manufacturers (as well as Cobalt's previous generation materials), rely on a combination of metallic fibers and resin as a source of primary structure (metallic powders also contribute when used in formulations requiring higher compaction pressures (above 10tsi, generally speaking), but to a lessed extent). As a resin-based material is heat cycled, the resin outgasses and at temperatures approaching and exceeding 1000F, begin to decompose; this is why you will see resin-based materials crumble and chip at the edges after multiple heat cycles. The Cobalt XR-Series materials, being based on hybrid sintermetal technology, are compacted at much higher tonnages (exceeding 20tsi), do not utilize metallic fibers, and achieve structural integrity via controlled atmosphere (nitrogen/hydrogen mix) sintering processed at temperatures exceeding 2000F. Thus, they possess much higher performance consistency over the life of the pad, both during a given session/race, and also when run after multiple heat cycles; e.g. pads that are used 3 weeks after a race still have the same performance characteristics as a new set.

Traditional sintermetallic compounds contain upwards of 50%-V metallic powders or fibers. Cobalt Friction has developed a method of sintering which permits a much lower metallic powder content, with maximum of 30%-V, and allows neck formation between metallic, ceramic, and carbon particles. The result is a material that is 70%-V carbon-ceramic, yet still maintains excellent structural integrity at temperature exceeding 1600F. Similarly, the high carbon-ceramic (5 types of carbonaceous materials, and 4 types of ceramic materials) content lends itself to a much higher specific heat capacity (joules per gram per kelvin) (up to 50% higher than traditional resin-based materials).

Lastly, please note that LG Motorsports is the exclusive supplier for Cobalt XR-Series brake pads for Corvette fitments (C5 and C6); please contact LGM directly.

Regards,

__________________
andie w lin
director of motorsports r&d
cobalt friction technologies

RK, yeah the pad table is old but I felt it was still useful. I use Cobalts at the track. Carbotech XP10/XP8 and Cobalt XR1/XR5 and Cobalt XR2/XR5 are the 2 brands of track pads that I have personal experience with, and I recommend either one. The link you provided is a good discussion. I can't add anything to the original post, its too big already. I have never found the need to buff, scrape, sand or mess with my rotors, a good rebedding is all I've ever done and I have gone back and forth with track pads and street pads many times with no issues. You can really remove a lot of pad deposits if you encounter them just by getting REALLY SERIOUS with the bedding procedures. I no longer encounter them because I use street and track pads adequate for the task at hand.

I recently went to have my brakes checked and the manager stated I needed new rotors. Six months ago I had my brakes checked and was told my pads were fine with 60% pads still left. Less than six months go by and less than 5000 miles later I need new rotors. Not only that but I was to be charged $800 becuse I had a sport tuned suspension and needed special "KUKI" rotors. I thought this was stanrge when I went to the dealer and he said my rotors were fine I just needed new pads and they needed to be machined. Again, another $500 . Is this accurate or is someone about to make some money off me. Not a total mechanical idiot but I do realize when people are trying to bend me over. Any opinion would be greatly appreciated.

Can't say for certain, I wasn't there and didn't examine your car, but from your description it sounds like you were hosed a bit. The only time you need new rotors is if they are below the minimum thickness (and it takes quite a few miles or some heavy track time to do that, I posted the minimum thicknesses in post #8) or you have let the pads wear down to the backing plate and you have seriously scored the rotor face. Even then it could probably be machined. New OEM type blank rotors aren't that expensive. There is nothing special about the RX8 rotors or the sport suspension other than that they are bigger than the base model. I've never heard of Kuki rotors, I think the service manager was kookie! Even if you did need front rotors on a high mileage RX8 it is likely that the rears would still be OK. A lot of shops will sell you new rotors because they can, just like the oil change shops that want to sell you an engine flush or whatever. No way to tell in hindsight about the pads. One thing about pads is that when you have 50% thickness left you don't have 50% life left. The wear rate increases as the pads get thinner.

I bought the car at 25,000 just now reached 31,000 . I thought the estimate was a bit expensive especially since when I went to the Dealership they said I have 10% left on my pads and would just need my rotors machined. The pads you say I can use are standard OEM pads. Is it accurate to be charged almost $400 (for standard OEM pads) just for two new front pads only. I also get excessive amounts of brake dust from the pads and seems like I am cleaning them everyweek (not necessarily a bad thing). Is that normal or should I look for specific pads to solve that prob.

I bought the car at 25,000 just now reached 31,000 . I thought the estimate was a bit expensive especially since when I went to the Dealership they said I have 10% left on my pads and would just need my rotors machined. The pads you say I can use are standard OEM pads. Is it accurate to be charged almost $400 (for standard OEM pads) just for two new front pads only. I also get excessive amounts of brake dust from the pads and seems like I am cleaning them everyweek (not necessarily a bad thing). Is that normal or should I look for specific pads to solve that prob.

I'm surprised that a car with that low mileage only has 10% pads left. Maybe the prior owner was riding the brakes all the time or is it an automatic which may wear faster. I don't know the exact going rate for OEM pads but I would guess they are about $150 a pair. The rest of the $400 is labor, welcome to automotive maintenance. Learn to DIY if money is the object.

Brake dust is normal, how much depends on the driver and the pad. General rule of thumb is performance pads (higher temp/broader range) dust more than OEM. OEM pads for the RX8 probably dust more than the OEM pads for the Mazda 3. Some people like the Hawk ceramics for the RX8 and claim less dust, I have no experience with them so I can't comment.

I used to have very dusty performance pads on my previous FWD Acura so to me the OEM RX8 pads are pretty clean, its all relative.

Justjim,
thanks for detailed and insightful FAQ post! I have a bit of an oddball followup question, hopefully it's not too divergent from the topic:

I've bled my brakes before, and I've swapped pads before, but never did them at the same time. This next time, I'd like to do both at the same time. So the question is, is there any logic as to which order you'd do these 2 things? I wanna say it's no big deal either way...but perhaps it'd be ideal to swap pad first, then do the bleeding?

GULAMAN

I tried to go back and correct the brake size for the AT sport but I'm at the word size limit for a single post so I can't add to it:eek:. Good catch on the AT brake size info.


Assuming I wanted to order new rotors from racingbrake, if i ordered the 12.7 in rotor would it work fine on my AT (base...:banghead:)

Justjim,
thanks for detailed and insightful FAQ post! I have a bit of an oddball followup question, hopefully it's not too divergent from the topic:

I've bled my brakes before, and I've swapped pads before, but never did them at the same time. This next time, I'd like to do both at the same time. So the question is, is there any logic as to which order you'd do these 2 things? I wanna say it's no big deal either way...but perhaps it'd be ideal to swap pad first, then do the bleeding?

GULAMAN

Ultitmately you could do it either way, but there is a reason to do the pads first. Let's say your plan is to bleed the brakes not replace all the fluid. If you install new pads you will have to push the pistons into the calipers and this will cause the fluid to rise in the master cylinder reservoir. If you have already bled the brakes you may end up wasting fluid. If you do the pads first the fluid will be near full and you won't end up adding as much fluid. Other than that its a wash either way.

Assuming I wanted to order new rotors from racingbrake, if i ordered the 12.7 in rotor would it work fine on my AT (base...:banghead:)
No it wouldn't. The base caliper pistons and the rear proportioning valve will have been sized for the smaller base rotor. Even if the larger rotors physically fit on the brackets (unsure) you will have degraded the brake bias front to rear and the car will not stop as quickly as it would have with the base rotors. You would have to replace the front rotors, front caliper, master cylinder, and rear proportioning valve and possibly the ABS unit to get it to function as the sport GT system.

Ultitmately you could do it either way, but there is a reason to do the pads first. Let's say your plan is to bleed the brakes not replace all the fluid. If you install new pads you will have to push the pistons into the calipers and this will cause the fluid to rise in the master cylinder reservoir. If you have already bled the brakes you may end up wasting fluid. If you do the pads first the fluid will be near full and you won't end up adding as much fluid. Other than that its a wash either way.

Thanks...that was sort of my thinking as well.

Wow base model totally got fucked over then... god damn... ugh no LSD or 18" rims, no HIDS no traction control... damn i could go on forever...



No it wouldn't. The base caliper pistons and the rear proportioning valve will have been sized for the smaller base rotor. Even if the larger rotors physically fit on the brackets (unsure) you will have degraded the brake bias front to rear and the car will not stop as quickly as it would have with the base rotors. You would have to replace the front rotors, front caliper, master cylinder, and rear proportioning valve and possibly the ABS unit to get it to function as the sport GT system.

Wow base model totally got fucked over then... god damn... ugh no LSD or 18" rims, no HIDS no traction control... damn i could go on forever...

just to be clear the base model rx8 is not an automatic and comes with the LSD and 18" wheels. Just no traction control (along with other bells and whistles).

Yeah, I may have oversimplified the RX8 models in the FAQ. Apparently you can get the larger brakes in the automatic transmission if you get the sport GT suspension. If you have the stick shift you have the larger brakes regardless of trim. Is this right? If so I will try and go back and find room to alter the original post.

Edit: Changes made

This FAQ is good. The only thing I would add is that if people are looking for a straight OEM rotor replacement, the Centric rotors are a good, cost effective option. I had to search for a while before I found them.

sticky please. i had to go digging for this. thanks!

just to be clear the base model rx8 is not an automatic and comes with the LSD and 18" wheels. Just no traction control (along with other bells and whistles).

he's speaking about the base automatic model. :)

Great read justjim.

Justjim very well done.
I spoke with Hawk today and they advised me that the DTC 70 were not available for the 8.
I believe the available Hawk track pads for the 8 include DTC60, HT-14, HT-10, 9012 blues
I had gone thru a couple sets of the Mazdaspeed pads and like them.
I have been told by several people that the MS pads are Hawk blues.
Mazdaspeed tells me that they are sourced from Japan and are not Hawk Blues

Justjim very well done.
I spoke with Hawk today and they advised me that the DTC 70 were not available for the 8.
I believe the available Hawk track pads for the 8 include DTC60, HT-14, HT-10, 9012 blues
I had gone thru a couple sets of the Mazdaspeed pads and like them.
I have been told by several people that the MS pads are Hawk blues.
Mazdaspeed tells me that they are sourced from Japan and are not Hawk Blues

I edited the DTC70 to DTC60. I would be surprised if the MS pads were Hawk Blues. I have no personal experience with either one, but this is a description of Hawk Blues from the Stoptech website.
The venerable Hawk Blue is a race pad with the temperature range of a club race pad, very high rotor wear at cooler temperatures, and low to moderate rotor wear when warm. You can also expect a stable torque curve, good bite, and a MOT of 1,050°F. It works well for track use in the front of front engined cars for less experienced drivers, but advanced drivers can overheat this pad on medium to high mass vehicles.
I know some people who only use Hawk Blues to sand off the pad deposits of other pads because of their low temperature abrasiveness. They are old technology and in my opinion there are better pads out there. 1050F is only a 100degrees higher than Axxis Ultimates and 150 degrees higher than Hawk HP Plus.

I have used the Carbotech XP10 and XP8 track pads and like them. Based on that the Carbotech AX6 might be a better choice, although I have never used them either. This is from the Carbotech website www.ctbrakes.com
The AX6™ takes the place of the Panther Plus™ compound that was so successful. AX6™ was specifically engineered for Autocross applications. A high torque brake compound delivering reliable and consistent performance over a very wide operating temperature range (150°F to 1250°F +). Advanced compound matrix provides an excellent initial “bite”, high coefficient of friction, and very progressive brake modulation and release characteristics. AX6™ offers high fade resistance, rotor friendliness at all temperatures, excellent cold stopping power, and non corrosive dust. As a result, AX6™ is an excellent choice for Autocross & novice track day drivers and beginner high performance driver education (HPDE) drivers on street driven cars using street tires eliminating the need to change brake pads at the track. AX6™ has gained tremendous popularity with SCCA Prosolo/Solo2 competitors for its fantastic bite, release & modulation. Many drivers use the AX6™ for street driving as well, even though Carbotech doesn’t recommend street driving with AX6™ due to possible elevated levels of dust and noise. AX6™ is NOT a race compound, and should not be used as such. AX6™ shouldn’t be used by any intermediate or advanced track day drivers, and should not be used with “R” compound tires (racing tires). Cars in excess of 300hp and/or 3,000lbs should not use AX6™ for any track use.

Can anybody give me the part number for Ferodo DS2500 for spurt suspention. Local Ferodo dealer claims that DS2500 are not produced for RX8.

Can anybody give me the part number for Ferodo DS2500 for spurt suspention. Local Ferodo dealer claims that DS2500 are not produced for RX8.

I did a quick Google search and couldn't find any either. I included the DS2500 in the Brake FAQ because they were available for my previous car (Acura) I just assumed they were available for the RX8. If they turn out to be unavailable try calling Carbotech and get some Bobcats or AX6s.

good read :bigok:

I did a quick Google search and couldn't find any either. I included the DS2500 in the Brake FAQ because they were available for my previous car (Acura) I just assumed they were available for the RX8. If they turn out to be unavailable try calling Carbotech and get some Bobcats or AX6s.

I assume ds2500 are not availavle for us. will go with the HP+. Thanks.

Very good read man. Thanks for this. It's funny because I'm planning to upgrade my brakes come May, but this gives me a better insight as to what I should do. Thanks again.

Hey Jim you can utilize your post below your OP to split up the OP into two sections so you can write more and not be word count limited

Hey Jim, what about the Axxis do you like better then the Hawk HP Plus? I'm just on the fence about if I should be getting the Plus's or the Axxis Ultimates. I have Hawk HPS right now and my car stops great on the course but not as hard and quick as I'd like. I'd like to brake a little later and quicker. upgrading to stainless steel lines and going to flush the whole system, but still running stock rotors that are in great shape. Lemme know what you think! :)

Well I've only used the Axxis Ultimates on my previous car, a FWD Acura that was more braking challenged than my RX8 and they performed well but were dusty. I use the OEM pads for my RX8 on the street and switch to Cobalt XR2/XR5 track pads at Sebring. I've never used the Hawp HP plus but alot of people do with good results. Their max temp is comparable to the Axxis Ultimates, maybe 50F less, and they dust alot also so its probably a toss up. Compare prices and go from there, and be prepared to clean your wheels.

Edit:
You might also check out Carbotech brakes at http://ctbrakes.com/brake-compounds.html the phone number to order is on the webpage. Take a look at the AX6, I've had good results with the Carbotech track pads in the past.

Thats good to know. Thanks a lot for the recommendation Jim. :D

Where is the rear proportioning valve, I cannot find it in the parts catalogue in any of the related sections.

I can't find one in the repair manual either, maybe there isn't one after all. The reference was a carry over from another FAQ based on my previous FWD car which had one. Since the RX8 has approximately 50/50 weight distribution they may have been able to handle rear proportioning with the caliper piston diameters and ABS alone. If no one can find one I'll revise the FAQ text.

I just tracked a set of carbotech xp10 front and xp8 rear with motul 600 at Road america and never experienced fade at any part.

And for those wondering about brake bias, the 8 used EBD, electronically controlled braking bias. It basically will give the rear brakes enough braking power up until just before they lock up so you never have a loose rear end. You can get all 4 wheels to lockup, trust me I've done it on stock pads, but the fronts lock up before the rears to make sure the car is still stable in the emergency stop.

And you do want to make sure your brake fluid reservoir ISN'T completely full as it will make the rear pads drag a little. The rear pads release after the front release if I remember the info correctly. I experienced this and noticed a streak develop across the outer edge of the rear rotors.

Is this statement at all true about dual rotors?

"They need constant service they are designed 4 racing and the 2 come apart and be re tightened and torqued"

... above was communicated to me from someone that races a lot.

Is this statement at all true about dual rotors?

"They need constant service they are designed 4 racing and the 2 come apart and be re tightened and torqued"

... above was communicated to me from someone that races a lot.

You're referring to 2-piece aluminum hat rotors?

Is this statement at all true about dual rotors?

"They need constant service they are designed 4 racing and the 2 come apart and be re tightened and torqued"

... above was communicated to me from someone that races a lot.

i have not found that to be true.

have been running two piece with alum hats for about 30 k miles. including 5 track days.

are you talking about after changing a rotor on the hat? and checking after?

beers :beer:

I would like to know if anyone has weighed the smaller front caliper and disc from the automatics. Just curious to see if they are significantly lighter.

Porterfield makes Cermaic brakes and they all go up to 1400 degrees including the R4

Been using them for years. I still have a pair of the first lot they made for the RX8 in the garage. Slight used good for street but I like new pads for the track.

i have not found that to be true.

have been running two piece with alum hats for about 30 k miles. including 5 track days.

are you talking about after changing a rotor on the hat? and checking after?

beers :beer:

Racing Brake claims you don't have to re-torque their rotors.

They have special designed harware.

No it wouldn't. The base caliper pistons and the rear proportioning valve will have been sized for the smaller base rotor. Even if the larger rotors physically fit on the brackets (unsure) you will have degraded the brake bias front to rear and the car will not stop as quickly as it would have with the base rotors. You would have to replace the front rotors, front caliper, master cylinder, and rear proportioning valve and possibly the ABS unit to get it to function as the sport GT system.

They won't fit on a 16" wheel.

bump for stickage^^

bump for stickage^^

working on it..

btw,

chatted with tom today at colbalt. :) to funny.

beers :beer:

Hmmm weird that I never seen this but SUBSCRIBED

I would say that drilled and slotted still look sexy:yesnod: and worth the money if you need to replace rotors...you can always just get slotted if your afraid of cracking with the drilled holes:yesnod:

thanks for the info on bedding in properly!

hey guys what about the mazdaspeed brake pads are they any good??? i wanted to get some soon

hey guys what about the mazdaspeed brake pads are they any good??? i wanted to get some soon

i like em. ;)

thanks dondo, since were on the topic of MS is there exhaust any good aswell. im thinking of mazdaspeeding my whole rx8 lol

Please start another thread if you have questions other than brake background.

i have already asked these questions in the threads there suppose to be in but no 1 freaking reply's???

you can pm me about ms stuff if you want

Carbotech no longer makes any of the panther series pads. The panther pads have been replaced by the bobcat 1521 and AX-6 compounds.

I believe Mazdaspeed now sells the AX-6 but I am having a hard time finding a place that sells the bobcat pads.

From what I have read so far the AX-6 seems like a Great pad. I would like to see reviews of the bobcat.

Go to the source, call Carbotech at 1-877-899-5024 and order them direct from the factory and you will be able to speak with knowledgeable people. Tell them Jim Dozier referred you (maybe they will give me a discount on my next order:mdrmed:) go to the Carbotech website at www.ctbrakes.com for more info on their current pads. Carbotech Bobcat 1521s are still available.

I know the panther series was at one time available ( but no longer widely accessible. ) and was just trying to list what was currently offered that seemed like a good compromise as far as comparable pads mentioned earlier in the post. I would love to hear more from some one that has used there newer compounds from Carbotech for a bit of time on the street.

Comments?

EPIC post, good sir.

I replaced my brakes with new brake pads, rotors, brake lines and flushed the brakes after. I did my brakes before and had no problem, used same pads before which are Hawk Hps pads. My first dilemma was that the rear brakes were a tight fit, they are pretty much touching the rotors. The fron rotors and pads were fine after replacement. I flushed the brakes no leaks. Test drive the car and rear rotors are rubbing to a point where the car stops on its own, and the brke paddle pretty much is going down to the floor. I am going to flush the brakes again on friday and let the car sit till then, let me know any suggestions or fixes anyone can advise.

Thanks

Wow. Thanks for this faq. This is going to come in handy.

If the brake pedal is going to the floor it sounds like you didn't bleed the air out of the system when you installed the new lines. Remember that hydraulic fluid can't be compressed, but air can!

A slight drag on the rotors is normal, presuming you properly retracted the caliper pistons to begin with. 'Stopping on it's own' is a bit vague, since all cars will eventually stop on their own. ;)

I replaced my brakes with new brake pads, rotors, brake lines and flushed the brakes after. I did my brakes before and had no problem, used same pads before which are Hawk Hps pads. My first dilemma was that the rear brakes were a tight fit, they are pretty much touching the rotors. The fron rotors and pads were fine after replacement. I flushed the brakes no leaks. Test drive the car and rear rotors are rubbing to a point where the car stops on its own, and the brke paddle pretty much is going down to the floor. I am going to flush the brakes again on friday and let the car sit till then, let me know any suggestions or fixes anyone can advise.

Thanks

I replaced my brakes with new brake pads, rotors, brake lines and flushed the brakes after. I did my brakes before and had no problem, used same pads before which are Hawk Hps pads. My first dilemma was that the rear brakes were a tight fit, they are pretty much touching the rotors. The fron rotors and pads were fine after replacement. I flushed the brakes no leaks. Test drive the car and rear rotors are rubbing to a point where the car stops on its own, and the brke paddle pretty much is going down to the floor. I am going to flush the brakes again on friday and let the car sit till then, let me know any suggestions or fixes anyone can advise.

Thanks

It may be that you didn't screw the rear pistons in far enough to reset the automatic adjuster. Some people have commented that you have to screw it all the way in, not just enough to put the new pad in. Make sure the piston is screwed all the way in first then check the pad fit. Also make sure that if there is a pin on the back of the pad that it is in the slot on the piston. The slot should be parallel to the direction of pad insert, so the pin will slide ride in. It is easy to mess this up as it is hard to see so spend some time to make sure it aligns properly.

If your rear pads were too thick for some reason that would just aggravate the situation. You may have to shave the pads down for proper clearance.

Good point on the pad (shim) pins in the piston slots. See the "Rear Brake DIY" for some excellent pictures to illustrate the proper fitment.

Thanks, I'll do all that and post an update. Thanks again.

I'm a bit perplexed by some conflicting information I'm coming across elsewhere. In motorcycles, sintered brake material seems to be fine for street use; but the only definitely sintered pads for the RX-8 that I've been able to find are the ones from Project Mu, which are strictly for racing, based on their quoted temperature range. The Carbotech pads that don't use a binder appear to be a variant of sintered technology but using more pressure and less heat to form, assuming I understood their description properly (I know that's a huge "if"). I'm now debating between Project Mu Type NS, EBC Yellowstuff, possibly Cobalt XR2/XR5 (XR2 front XR5 rear), and a few others, trying to narrow my decision pool down.

I'm not really concerned about the cost of the pads; but I do want good cold bite, high torque across the thermal range, and a good high temperature ceiling. I'm looking for a pad that can be used safely for a daily driver; but could also safely endure a track day or HPDE school (and still be safe enough to drive home afterward). I also want to keep the rotor wear low. The last two qualities, if I were to put together a wish-list would be low squeal and low dust. I am willing to deal with increased cost to achieve as many of those points as I can. My RX-8 is a 2004 with roughly 45K miles and still on the original OEM pads.

I did read through this FAQ, as well as the track day brakes thread and regret I still can't piece together an answer; but I know there are people here who have more experience and knowledge than I have and I'm not going to stick my head in the sand because I'm too proud to admit I can't figure it out on my own, even after reading through the various brake threads here and elsewhere.

I'm a bit perplexed by some conflicting information I'm coming across elsewhere. In motorcycles, sintered brake material seems to be fine for street use; but the only definitely sintered pads for the RX-8 that I've been able to find are the ones from Project Mu, which are strictly for racing, based on their quoted temperature range. The Carbotech pads that don't use a binder appear to be a variant of sintered technology but using more pressure and less heat to form, assuming I understood their description properly (I know that's a huge "if"). I'm now debating between Project Mu Type NS, EBC Yellowstuff, possibly Cobalt XR2/XR5 (XR2 front XR5 rear), and a few others, trying to narrow my decision pool down.

I'm not really concerned about the cost of the pads; but I do want good cold bite, high torque across the thermal range, and a good high temperature ceiling. I'm looking for a pad that can be used safely for a daily driver; but could also safely endure a track day or HPDE school (and still be safe enough to drive home afterward). I also want to keep the rotor wear low. The last two qualities, if I were to put together a wish-list would be low squeal and low dust. I am willing to deal with increased cost to achieve as many of those points as I can. My RX-8 is a 2004 with roughly 45K miles and still on the original OEM pads.

I did read through this FAQ, as well as the track day brakes thread and regret I still can't piece together an answer; but I know there are people here who have more experience and knowledge than I have and I'm not going to stick my head in the sand because I'm too proud to admit I can't figure it out on my own, even after reading through the various brake threads here and elsewhere.

Project Mu would be a 4-6 week wait time, last time I talked to the major US Distributors they were no longer going to be stocking Project Mu for the RX-8. Great pads none the less.

As for the EBC Yellow I have heard good and bad feedback, but none of the feedback I have received about them were from an RX-8 application.

As you can see from the these reviews very mixed feedback.

http://www.ek9.org/forum/brakes/14780-ebc-yellow-stuff-review.html



As for Cobalt I will leave that to others to comment, they are great pads as well from what I hear from fellow members.


Another Pad to look at is the ET800 from Racing Brake, I have had some great feedback from people that are heavy spirited drivers as well as those that take them to the track. They have great cold bite, excellent modulation and no fade up to 1400 Deg F.

This by far is one of the most interesting reviews that I have come across from the ET800 and up series pads. Especially from a Z06 owner I was impressed.

http://forums.racingbrake.com/showthread.php?t=313


Also Hawk Hp + is favorite of mine as well I swap between these and the 800-900 series pads from AutoX to track use. I have yet to use the 900's yet but I will be posting a review after I get back from RRR.

If you decide on Racing Brake or Hawk let me know we stock all of their compounds in house even the HT-10's as well.

Hope this gives a little more insight and others can add to the cobalt feedback.

longpath I think you are overthinking the issue. A couple of points that may not have been clear in the Brake FAQ. There are street/performance pads and there are track only pads. Whether you can use a street/performance pad at the track depends on 2 things, your level of skill and the nature of the track. If you are new to tracking and/or the track is not brake intensive, you may be able to use a street/performance pad at the track. However, if you have progressed in your skill and/or the track is brake intensive you will eventually find that you will benefit from a track only pad.

Why are certain pads track only and not recommended for street use?
1. They are more expensive, this doesn't bother the rich.
2. They perform better at track temperatures, although some modern track pads perform OK at street temps and can be used to travel to the track.
3. They are harder on rotors.
4. They won't last as long as street pads.
5. They are noisier.
6. They are dustier, and some have corrosive dust.

Some people get by with lower level track pads on the street despite the above issues. Carbotech XP8s will fit this bill. Its a compromise. All performance pads will dust more than OEM. Some of the "ceramic" pads are low dust but they probably have lower thermal range than the OEM, fine for street but not the track. Ceramic is a bit of marketing hype as many of the track pads also have "ceramic" compounds in them as well. Just think low dust and high dust.

If you are relatively new to tracking and want to use the same pad on the street and track I would suggest Carbotech Bobcats or AX6s, Axxis Ultimates, or Hawk HP Plus. There are others that may fit the bill as well. Keep in mind that as you progress none of these pads will hold up to serious use on the track by a good driver.

By the way virtually all pads include a high content of some kind of powdered metal, iron, brass, aluminum or other pressed into or bound into the complex component mix. A true sintered metal pad would be essentially 100% metal such as brass. The Cobalts (not Carbotech) press theirs rather than use binders but that mostly relates to bedding procedures.

Thanks Racing Roots and JustJim. I think that gives me what I was missing, and you're right, I have a terrible habit of overthinking, so I very much appreciate both you helping me out.

Justim is pretty much right on. I run CarboTech XP10 up front and the XP8 in the rear and they do need some heat to really bite well. They do work well on the street as they have decent bite cold.

There are always tradeoffs and you have to find the mix that is right for you. I like knowing that when I hit the track I can drive deep into the corner and scare the shit out of the passenger and not have to worry about brake fad. But then I'm constantly cleaning the car and have squeaky brakes everywhere I go.

Thanx justjim very informative answered all the questions I had......I have a base A/T an thought I could just swap to sport suspension and then go sports sus brakes Man I was wrong

so ive read all this and maybe i missed it but hopefully i didnt.

based upon whats been said, the BBK's dont really help stop the car faster due to the ABS.

now when racing i know lots of racers actually race, they turn off their ABS. (includeing me)

so with ABS off and it not interfering with the car, would a BBK on the rx8 yeild benefits?

...will squeal Beethoven's fifth symphony if you don't shim and grease their backs,

Since some greases run different temps maybe a use/do not use. Such as the regular black silicone washes out and breaks apart at 500deg. I've recently used the Permatex Ceramic with good results - supposedly good for 2000deg. Then there's the silver stuff, the copper stuff. Not being a bonehead and forgetting to grease your slides everytime you change pads, etc.

Loctite Copper Grease works great. It's high temp resilient.

Grease anywhere the backside of the pads contact the caliper and also the pad slide channels. Of course don't get any on the pad-rotor contact surfaces.

The "brake rebuild kit" is like 10 dollars. make the investment... and I use synthetic high temp greese

so ive read all this and maybe i missed it but hopefully i didnt.

based upon whats been said, the BBK's dont really help stop the car faster due to the ABS.

now when racing i know lots of racers actually race, they turn off their ABS. (includeing me)

so with ABS off and it not interfering with the car, would a BBK on the rx8 yeild benefits?

anyone?

so ive read all this and maybe i missed it but hopefully i didnt.

based upon whats been said, the BBK's dont really help stop the car faster due to the ABS.

now when racing i know lots of racers actually race, they turn off their ABS. (includeing me)

so with ABS off and it not interfering with the car, would a BBK on the rx8 yeild benefits?

I'll try to keep this simple, the first thing to remember is the tires stop the car, the brakes just stop the tires. If the current brake setup can lock up the tires at will at some particular desired speed, putting a BBK won't stop the car any faster. It will however improve the resistance to fade. If fade is a problem with the current setup then yes the BBK will stop the car faster under those conditions that previously induced fade.

Your interpretation of why the BBK does not generally stop the car better is off the mark a bit. There is the issue of the tires actually stopping the car I mentioned above but also that in some cases a BBK may increase stopping distances. It's not the ABS that is the problem, it is the potential for inappropriate braking bias, that is the imbalance between the front and the rear brakes, which can sometimes result from a poorly designed (or poorly matched for your vehicle) BBK to prematurely activate the ABS at one end of the car and actually increase stopping distances. However, if you turn off ABS the problem will not only be increased stopping distances but loss of control and the higher biased end will lock up the brakes prematurely. My feeling is that, on a road course (not an autocross) unless you have a manual proportioning valve or adjustable twin master cylinder setup you should leave the ABS on when at the track. It won't significantly increase you stopping distances and for most of us mortals will decrease the distance and allow you to keep control of the vehicle under threshold braking.

Appreciate this great thread, it was very helpful. I've talked to a few mechanics and they don't want to install brakes I buy and bring to them, well they'll do it but say other than proper installation they make no guarantees. I was going to just get the ones they normally provide. Anybody w/ experience with the quality of brakepads/rotors replaced by placing like Sears, AAMCO, firestone, etc? I saw sears sells Satisfied Gransport GS-6 ceramic pads which on tirerack seem to have decent ratings. Not sure about the other places.

Appreciate this great thread, it was very helpful. I've talked to a few mechanics and they don't want to install brakes I buy and bring to them, well they'll do it but say other than proper installation they make no guarantees. I was going to just get the ones they normally provide. Anybody w/ experience with the quality of brakepads/rotors replaced by placing like Sears, AAMCO, firestone, etc? I saw sears sells Satisfied Gransport GS-6 ceramic pads which on tirerack seem to have decent ratings. Not sure about the other places.

My opinion is you are best served if you can find a mechanic who is not locked into a particular brand of brake pad. If you are using a shop like you described above they are using a particular brand and probably won't deviate from it. I would try to find someone who will at the very least get you the OEM Mazda pads. The Mazda OEMs are pretty decent for street use and probably better than alot of the standard OEM replacement pads. If you find the right mechanic and if you are tracking the car, maybe if you let him add his normal markup, he'll order some aftermarket pads of your choice .

I used Satified Grand Sport 5s on a previous front wheel drive car and my opinion was ehhh not so much, there are better pads out there.

The real answer to all of this is DIY.

My new brake pads whistle all the time. My mechanic cleaned them many times but the problem still exists. I don't know if I buy the oem brake pads will give a solution to this headache...

My new brake pads whistle all the time. My mechanic cleaned them many times but the problem still exists. I don't know if I buy the oem brake pads will give a solution to this headache...

Make sure he used the OEM shims and greased the back of the backing plate and shims. You should be able to get rid of the squeal. Some pads have a tendency to squeal more than others but I can even get my track pads to be silent if I do what I described above.

Great thread.
Thanks for all info.

Jim, as everyone did say, this is a GREAT review indeed :worship:

I was about fork out a wide load of cash if it wasn't for this thread.

BTW, I found www.thepartsbin.com (http://www.rx8club.com/www.thepartsbin.com) which offered OEM spec rotors for only $63 a pair - these are made by EBC.

I'm sticking with stock rotors and hawk hp plus since it almost does the same result since the braking system of our cars, along with ABS does a lot of the work already.

Slotted would be great of a car does not have ABS - which I experienced locking my brakes and killing cones during auto-x :doh:

correction: those were $63 per rotor. I decided the EBC dimpled and slotted. They do give further discounts when you call or use the chat box compared to what is posted.

:confused:Our blue beastie, 2004, failed it's safety inspection, the rotors are shot, rusty, maybe cracked. still stops good in spite of minimal pads on front, but we were told that no aftermarket rotors work well and that we need to do original replacement rotors, don't know about pads. I would think that if aftermarket rotors are so bad, I would have seen this here, so we're not sure what to do. Help/advice would be appreciated, thanks.

aftermarket rotors are not 'bad'. they're lying to you.

:confused:Our blue beastie, 2004, failed it's safety inspection, the rotors are shot, rusty, maybe cracked. still stops good in spite of minimal pads on front, but we were told that no aftermarket rotors work well and that we need to do original replacement rotors, don't know about pads. I would think that if aftermarket rotors are so bad, I would have seen this here, so we're not sure what to do. Help/advice would be appreciated, thanks.

Comlete and utter nonsense. Rotors are only shot when they are worn below the minimum thickness (which requires measuring with a micrometer), or if they are cracked which is not likely on a daily driver unless you also track the car (and you would certainly know it if they were cracked). Rust is irrelevant. Pad deposits can be scraped off or machined off. Aftermarket rotors work as well as OEM rotors, blanks are best, slots don't really do much, and drilled rotors may be more likely to crack and don't do anything either.
Centric makes a good inexpensive aftermarket OEM blank rotor among many others.

Great Thread. I have a problem. I recently did my brakes and I am using cross drilled and slotted rotors from Brakelabs, and Hawk HP Plus pads. My previous setup was the same cross drilled and slotted rotors from Brakelabs but I used Bendix Ceramic pads from Autozone. I put them on and drove it and there was a lot of squeal. I figured I'd drive it and let them wear in, in hopes that they'd be fine. Its been 2 weeks and so I called Hawk Performance and told them my issue. The guy told me to take some sand paper and sand down the pads and then put them back on and take it on a road go up to 50-55 and go down to 5mph without engaging the ABS, I still had the issue. I went back into my garage and opened them up again and noticed the sliders that the caliper bolts onto weren't moving so I went to autozone and got some lubrication and lubricated it and it slides better but I still have that issue and I am finally a bit frustrated. I did spray the rotors down with brake parts cleaner a few times and took a paper towel and wiped it down too. The clips are in the right order and are not sticking out and touching the rotor at all so I thought of just about everything. Any help would be greatly appreciated.

so you only changed pads or rotors too?

Both man.

Great Thread. I have a problem. I recently did my brakes and I am using cross drilled and slotted rotors from Brakelabs, and Hawk HP Plus pads. My previous setup was the same cross drilled and slotted rotors from Brakelabs but I used Bendix Ceramic pads from Autozone. I put them on and drove it and there was a lot of squeal. I figured I'd drive it and let them wear in, in hopes that they'd be fine. Its been 2 weeks and so I called Hawk Performance and told them my issue. The guy told me to take some sand paper and sand down the pads and then put them back on and take it on a road go up to 50-55 and go down to 5mph without engaging the ABS, I still had the issue. I went back into my garage and opened them up again and noticed the sliders that the caliper bolts onto weren't moving so I went to autozone and got some lubrication and lubricated it and it slides better but I still have that issue and I am finally a bit frustrated. I did spray the rotors down with brake parts cleaner a few times and took a paper towel and wiped it down too. The clips are in the right order and are not sticking out and touching the rotor at all so I thought of just about everything. Any help would be greatly appreciated.

Brake squeal is caused by vibrations between the caliper piston and the back of the pad backing plate, not by the pad face and rotor interface. To minimize or completely eliminate squeal you have 2 tools,
1. high temp synthetic brake lube
2. the OEM pad shims

These 2 items work to dampen the vibrations between the piston face and the backing plate and work to minimize or eliminate the vibrations that cause squeal. You likely didn't use the OEM shims when you switched to the Hawk pads which are known to be noisy (some pads are more prone to squeal than others). Also, based on your description you only lubed the sliders and not the top, bottom, and most importantly the backs of the pads (obviously you don't want any grease on the pad friction face).

Get some OEM shims from the dealer if you didn't keep them, and put high temp synthetic brake grease between the shims and the pad backing plate, between the piston face and the shims, and on the tops and bottoms of the backing plate where it sits in the keepers. This should minimize or eliminate squealing.

Oh ok. My old pads had thin mettalic pieces which I decided to forgo so I will put them back on and re grease the pads. Thanks justjim, I appreciate it.

On Racingbrakes website it states that:

Weight Comparison
One-piece 18.5 lbs.
Two-piece 14.1 lbs.

and thats for the stock size


thecow135: you are correct... the sport and GT models on the AT's have the same suspension/brakes as the MT's

Do the 2004 AT Grand Touring models have sport or standard suspension??
Just wanting to double check cause I'm doing my brakes tomorrow.

Do the 2004 AT Grand Touring models have sport or standard suspension??
Just wanting to double check cause I'm doing my brakes tomorrow.

The AT Grand Touring have the sport suspension pkg.
Kinda of a day late and you may have already found this out.

I forgot about thsi thread.

So I did what justjim said and got OEM shims for my brakes. I noticed that the squeal was gone but it came back after a while and I still have it under light braking but the squeal is gone in heavy braking. I called up my rotor company and pad company (HAWK) and they said that it is probably just the pads and their compound and that race pads are louder. They told me that I should probably get some regular pads for the street and just switch over to my race pads when I track.

Also, the rotor company (brakelabs) said the same thing and that if my rotors have a grinding noise then I might need new rotors. Which I think my rotors are wearing a bit. I'd like to run my rotors for a while and try different pads, perhaps the OEM. What does everyone think?

Note on pad buildup on rotors:
I had this happen on my last session at Laguna Seca. I was getting to where i wasn't chicken lifting going through turn 1 and breaking pretty hard into 2. The pedal started pulsing, car shaking, thought it was a warpped rotor (I previously had a 300ZXTT that realy did warp rotors). Looked at the rotors after i got off the track and the were all blue and had some smear marks on them. Figured i would just drive it and see what happens. Well a week later with no special actions taken, its fine. Brakes are back smooth as ever and they don,t squeal like they did before the track day. This is on OEM pads.

Moral of the story, if your brakes squeal go to Laguna Seca and fix them.

^ think you got the moral wrong. If you go to Lagua Seca and drive fast, use real track pads/ not OEM pads or you'll get rotor deposit/melt the pads. Your pulsing pedal was likey just your ABS, even with traction control off, your ABS will work.

You are right that track pads would be a good upgrade befor the next track day. But the pulsing i was talking about was not the ABS. The first session that day was in pouring rain and i found out how well the ABS and DSC worked and what they feel like. As the tarck dried out I turned the DSC off and started pushing harder. After the last session the brakes pulsed for the whole 300 Mi. trip home and slowely went away over the next week.

justjim,

first of all thanks for this FAQ and your time.
The FAQ gave answers to the majority of the question I had about rotors and pads as I am planning to change them.

As I am "daily driver with only the occaisional spirited driving" after you FAQ I decided to buy OEM pads only.

As regards rotor I refer to your words "Aftermarket rotors work as well as OEM rotors, blanks are best, slots don't really do much, and drilled rotors may be more likely to crack and don't do anything either. Centric makes a good inexpensive aftermarket OEM blank rotor among many others. "

1) Do I understand you proprely that I will feel no difference if I buy blank Centric rotors intead of OEM rotors? Or OEM rotors are bit better than Centric?

2) I am really worry about buying cheaper Centric rotors (comparing to the OEM) if they do not provide the same safety comparing with OEM. Do you thing Centric rotors the same good as OEM rotors?

3) Have you used Centric rotors?

4) Whether pair Centric rotors with OEM pads is decent one?

5) There are 2 versions of each Centric rotor: (1) Premium Brake Rotor-Preferred and (2) Power Alloy Discs.
Could you please comment what is the difference and which one to choose best?

6) I have front sport suspension rotors with Automatic transmission. Kindly ask you to confirm that I have choosen properly the set of rotors for my RX8:

Front - Part number - 120.45071 (Sport Susp; A/T);

http://extranet.soleniuminc.com/CentricParts/Inquiry/..%5Cpart_images%5C12045071.jpg

Rear - Part number - 120.45072 (All)

http://extranet.soleniuminc.com/CentricParts/Inquiry/..%5Cpart_images%5C12045072.jpg

Many thanks for the help in advance!

Wizard 3000
The Centric rotors are a good choice for an OEM replacement. The ones you posted are a good choice. They make a power slot which is the same rotor with slots, I wouldn't bother to pay for slots. I used the Centric blanks on my previous FWD Acura which was a lot harder on brakes than the better braked Mazda RX8. I put about 16 track days on them in addition to about 50,000 miles. I use them on our Lemons racecar which only sees track time. I'm still on OEM rotors on my Mazda with 90,000 miles and 6 track days. You will not notice any difference with Centric blanks compared to the OEM.

In my opinion people worry too much about their rotors, and often make unsubstantiated claims to make themselves feel better about having spent obscene amounts of money on rotors. To me the only real improvement in the one-piece cast iron rotor is curved vanes which are available for higher cost. Two-piece rotors are an improvement for cars that see track time but the RX8 has excellent brakes and doesn't really need them unless the car is heavily modified. Track pads and ducting are more practical and cheaper. I track my RX8 with Cobalt track pads and R-compound tires and daily drive it with OEM pads all on the same OEM rotors. When they wear too thin or begin to crack I will replace them with cheap blank rotors, probably Centric.

Other people will have different opinions, many of which are influenced by marketing claims, something they saw on a more expensive car, or as I said above to justify money they already spent.
удача

justjim, thanks for you reply to my post! :bowdown:

Following you post I have made a search on Centric rotors for RX8.
Here is the table of the Centric rotors from the Centric's website:

http://i001.radikal.ru/1103/88/9f401f811041.jpg

I was trying to find Power Alloy Discs in onlinestores as the next Power Slot Slotted Brake Rotor are more expensive and differs only by slots which I don't need.
As I understand Power Alloy Discs should be better model than C-TEK Standard Rotor.

Unfortunately in all stores I called to I was told that they do not see anywhere Power Alloy Discs in stock.
So basically I have to buy either C-TEK Standard Rotor or the more expensive Power Slot Slotted Brake Rotor.

What do you think, what should I choose? :dunno:
What would you do in my place?

Thanks in advance for you reply.

... To me the only real improvement in the one-piece cast iron rotor is curved vanes which are available for higher cost. Two-piece rotors are an improvement for cars that see track time but the RX8 has excellent brakes and doesn't really need them unless the car is heavily modified. Track pads and ducting are more practical and cheaper...

All your other sage advice is spot on, but here, not so much. There's one piece and there's two piece rotors. I doubt many would argue one piece stop better, but you seem to miss the "reason to be". Two piece weigh considerably less, and therefore, as a heatsink, they are designed for better cooling to keep temps down, making them even more expensive for sure.

But the real point of improvement is weight reduction, and sprung spinning weight at that - and on all four corners of the car. I'm sure you'd agree pounds are hard to come by, and this is easy.

So the cost is not spent to improve braking but to lose weight and improve suspension dynamics. Modified or not is not the reason to be... and need is relative ;)

justjim, thanks for you reply to my post! :bowdown:

Following you post I have made a search on Centric rotors for RX8.
Here is the table of the Centric rotors from the Centric's website:

http://i001.radikal.ru/1103/88/9f401f811041.jpg

I was trying to find Power Alloy Discs in onlinestores as the next Power Slot Slotted Brake Rotor are more expensive and differs only by slots which I don't need.
As I understand Power Alloy Discs should be better model than C-TEK Standard Rotor.

Unfortunately in all stores I called to I was told that they do not see anywhere Power Alloy Discs in stock.
So basically I have to buy either C-TEK Standard Rotor or the more expensive Power Slot Slotted Brake Rotor.

What do you think, what should I choose? :dunno:
What would you do in my place?

Thanks in advance for you reply.

The Power Slots if you could find them and if you can afford them are a better rotor mostly because of the directional vanes. However, for a daily driver with OEM pads the C-Tek standard rotors are more than adequate and I would get them instead of the slotted ones. If the slotted ones come with directional vanes that would be the reason to get them, not the slots which are uneccesary.

It's all a question of how much money you want to spend and what you get in return. From a stopping distance standpoint, the C-teks are just as good. If you like a little bling and knowing you have directional vanes makes you feel warm and gooey inside then go for it. Otherwise don't lose any sleep over it.

All your other sage advice is spot on, but here, not so much. There's one piece and there's two piece rotors. I doubt many would argue one piece stop better, but you seem to miss the "reason to be". Two piece weigh considerably less, and therefore, as a heatsink, they are designed for better cooling to keep temps down, making them even more expensive for sure.

But the real point of improvement is weight reduction, and sprung spinning weight at that - and on all four corners of the car. I'm sure you'd agree pounds are hard to come by, and this is easy.

So the cost is not spent to improve braking but to lose weight and improve suspension dynamics. Modified or not is not the reason to be... and need is relative ;)

All of your salient points are echoed in the text of my Brake FAQ and I agree with everything you said. It's just that Wizard3000 is just doing daily driving with OEM pads and the rather large expense of 2-piece rotors seems like overkill and unecessary for his type of driving. It's a lot of money to reduce unsprung weight, better spent on lightweight wheels I would think, but you make a valid point.

justjim,
I don't even know how to thank you for your time and replies given.
Thanks a lot.
:icon_tup: :bowdown:

How about goove in the rotor? That would require resurfacing right?

How about goove in the rotor? That would require resurfacing right?

Grooves aren't as big a problem as you might think. The pads just wear to match the grooves. I have 90+K miles on my OEM rotors and a lot of track days and they are pretty groovy. My brakes are smooth as silk but they make a kind of whirring noise under hard braking that might be related to the grooves, but it's not worth the time and effort to turn the rotors. It's not the grooves I keep an eye on, it's the thickness and the surface checking from track heat cycles.

Grooves aren't as big a problem as you might think. The pads just wear to match the grooves. I have 90+K miles on my OEM rotors and a lot of track days and they are pretty groovy. My brakes are smooth as silk but they make a kind of whirring noise under hard braking that might be related to the grooves, but it's not worth the time and effort to turn the rotors. It's not the grooves I keep an eye on, it's the thickness and the surface checking from track heat cycles.

Thanks a lot. That's what I thought but as you know reading so many posts online about people turning their rotor because of grooves worries me. It is nice to have an expert for confirmation. :)

I bought cheap ass 30$ rotors on one car I have and they have nice ridges and grooves galore, but other than that it doesn't seem to matter much, at least for a DD car. On my RX-8 I have RB high quality rotors and before that the OEM rotors. Neither had grooves even after many many track days and much abuse. I think it's just a matter of the quality/strength of the steel used for the rotor blanks. Better, harder steel, less grooves.

I came in here looking for the thickness dimensions/specs on the front and rear rotors (more specifically their thickness prior to use/wear) and thought I was going to have to ask for the dimensions. Then I saw Wizard-3000's post (http://www.rx8club.com/showpost.php?p=3920276&postcount=115). Are those numbers accurate for a BNIB OEM rotor? 24mm front and 18.2 rear?

So I've tried searching and I can't really find what I'm looking for.

First I'll start with, I bought my car with 15k miles, it now has 17k. The brakes squeek every now and then, but it's only just louder then road noise. I just imagine it's dust/buildup. I know the car was tracked a couple of times, and I haven't bothered to take a look, but I'm assuming at the moment they're fine.

But when the day does come I need new ones, I was wondering what the OEM pads are, and where you can purchase them?

Also this is my DD, so quite and clean are preferred to heat resistance and resistance to fading. (I doubt i'll need to do 6 panic stops in a row, if I do I'll have bigger concerns then brake fade).

The brake pads that came on the car had a tendency to squeal. You should be due for a new front set. Just go to your auto parts store and tell them what your looking for when your set to replace them. They most likely have different brands and different models within each brand.

Hey, does anyone have the part number for a replacement kit for the brake master cylinder ?
Also any info on availability and cost.
THANKS

All of your salient points are echoed in the text of my Brake FAQ and I agree with everything you said. It's just that Wizard3000 is just doing daily driving with OEM pads and the rather large expense of 2-piece rotors seems like overkill and unecessary for his type of driving. It's a lot of money to reduce unsprung weight, better spent on lightweight wheels I would think, but you make a valid point.

Great thread Jim, any good resources for comparisons of the 2-piece rotors vs. the one piece, and who carries the 2-piece rotors?

I recently purchased an RX-8 race car! So somewhat new to the 8. The car has Cobalt pads on it now, sounds like you like them, I'll stay with them.

I believe TH Motorsports, one of the site vendors, has the 2 piece brake rotors available for our car. I don't know what organization or class you are racing your car in. Many more vendors have big brake upgrades available.

I believe TH Motorsports, one of the site vendors, has the 2 piece brake rotors available for our car. I don't know what organization or class you are racing your car in. Many more vendors have big brake upgrades available.

Thanks for the reply! It's an SCCA EP car. Truthfully I'm not even sure I can use the 2-piece rotors, but I need to put the car on a diet. The more I think about it, I probably can't :(

Justjim thanks for such an informative thread. I've one question. I believe I have build up on my rotors as you've described. Rotors and pads are stock. Can I simply rebed the existing rotors and pads to eliminate the pulsing or do I have to replace the pads with a higher temp pad to melt off residue? My 8 is 2004 A/T Touring.

"Use the steel wool and brake cleaner or Brillo pad to scrub off the build up. Since this deposit was emitted from the brake pads at high temperature therefore it may not be easy to remove the deposit without heating it up, in this case you will have to heat up the rotor surface with a torch and repeat the scrubbing with coarser steel wool."

read more here http://forums.racingbrake.com/showthread.php?t=73

CPA - I'm just down the road from you in Trophy Club. Let me know if I can be of any assistance.

Thanks Spin9K - great info