Spyerx

You need to switch to a more modern pad. Those yellows are stuffing too much heat into the rotors hence the cracking.

Pfc08 were similar to me.

I use race technologies re10 with good results. Endless and ferrodo have good pads. There are others out there but unloess you are looking for insane initial bite get an endurance pad. I don't like overly aggressive bite on a street car with abs and r comps. Endurance pads are much easier to modulate.

Errsomeone

Agree on he RE10s. Very easy to modulate. Data shows I adjust pressure quite a bit to adjust balance but rarely use all available. A pro I went out with also really liked them. Though, if you like very aggressive bite, these are not for you. But if want to slow more, press more and they work. Others I trust have positive experiences with Ferrodo.

Alan C.

My PCCBs are sitting in a cabinet in my garage. At 1900 miles I removed them switching to GiroDisc rotors and Ferrodo pads from Clark at Apex. I'm currently at 8500 miles and the rotors have lots of life left in them.

Spyerx

I just checked my records. I'm at 18 days on RE10 with Brembo Type 5 front type 3 rear. I'm not the fastest guy, not the slowest either... and my gt3 runs about same pace as a gt4 (hey its an antique!). Our track here I'd say are "medium" on brakes. Inspected car while cleaning it up yesterday, fronts are ~40% left, rears about 50% left. Rotors have LOTS of life.

So Joe isn't kidding with other options, and he's much faster than I am.

Jason @ Paragon Products

Pagid doesn't produce the 4924 pad shape in the black RS14 compound but they do make it in the newer RST3 compound which could be considered a similar/better sprint compound.

https://www.paragon-products.com/Pag...4924-pagid.htm

aryork

I had not heard about just replacing the iron, but called Essex and the AP J-hook front assembly (2 ea) are $1800 (rounding off), but once you buy them just replacing the iron is $880 (includes new hardware @ $40 each) for both fronts. OEM rotors are $1400 for both fronts from Suncoast. Saves $520 per front replacement if i did math right.

pvgolfer

My original set of OEM pads up front are just about ready for replacing. The original pads/rotors on the rear are fine (~75% remaining) and my front rotors are fine, so I’d just like to replace the front pads. Is it okay to switch out to the Ferodo DS 1.11 pads up front on the original rotors, while keeping the OEM pads/rotors on the rear? I’m wondering if I’ll run into issues with brake bias or problems with the original rotors due to a change in pad compound.

If a mixed setup is ill-advised, then I’ll go with another set of front OEM pads for the remaining track season and then swap everything (front/back) out for the AP rotors and Ferodo pad setup.

TIA for any advice/recommendations.

ShakeNBake

I have to admit I have never tried to run a staggered setup on a porsche yet. It's probably going to work when the car is in ABS and the brake force distribution is working to compensate for a change in mechanical bias. That said, you will probably notice it, and it would likely feel like the car goes into ABS too easily since you won't get as much braking help from the OEM rears, and that feeling will get worse as the rears heat up and lose friction. I'd keep it all the same until you are ready. Nothing wrong with taking the OEM pads off the rear early and keeping them until you sell it.

smmmurf

Agreed. This is not recommended. The difference in friction coefficient will produce unexpected behavior in braking and handling (given that brakes are used in torque vectoring and stability control as well).

pvgolfer

ShakeNBake/Smmmurf- Good info! Thanks!

JRitt@essex

Hello Gents...a few items:

Predicting pad and disc wear is more or less impossible due to the high number of variables in both the components themselves, and the conditions under which they are being run.

Tire choice, aero, increased horsepower, decreased curb weight, weight distribution, suspension modifications, driver braking technique, track layout, airflow to brakes, brake disc material, and brake pad material all have an impact on brake wear. Anything that impacts how your car leaves a corner and gets to the end of the next straight is going to change how your car enters and behaves in the subsequent brake zone. That makes comparing one owner's experience with another very difficult.

Pads
In terms of the brake components themselves, racing brake pads frequently contain up to 35 ingredients, adhesives, fillers, friction modifiers, resins, and lubricants. In professional-grade racing pads (such as the Ferodo DS series of pads), the primary pad compound sometimes sits atop a thermal underlayer. The thermal underlayer is a thin mix of material pressed between the backing plate and the friction material. The underlayer helps ensure proper binding of the pad compound to the plate, but is specifically designed to prevent heat penetration through the backing plate and into the caliper pistons and brake fluid.

The vast majority of racing pads also use some type of adhesive to bond the friction material/underlayer to the backing plate. Top-tier race pads typically also use some form of mechanical retention as an added safety feature to prevent the friction puck from delaminating (falling off the backing plate). As an example, a brass stud mechanical retention system is employed by Ferodo.

Racing pads also frequently have vertical grooves cut into their face. Just like your driveway or the highway, these expansion grooves provide space for the materials to expand and contract without fracturing as the pads are repeatedly heated and cooled to and from track temperatures.

One of the final processes in race pad manufacturing is called “scorching”. When pads are formed in a press, some quantity of binders or resins remain on the friction surface of the pad. During scorching, the friction surface is blasted with flames in an oven to burn out some of those surface resins. If those surface resins are not removed via scorching (and a proper bed-in), those resins can melt or vaporize during any initial hard braking events, leading to an unstable friction level. This phenomena is frequently referred to as 'green fade' (green as in new).

One can think of scorching as an incomplete form of bedding, or the step prior to actually bedding the pad on a brake disc. Scorching improves the likelihood of a successful bedding process by reducing the chance of uneven pad deposits on the disc face. Many race pads today are being marketed as "pre-bed," but unless the pad has actually been run on a disc face, they are only scorched.

Brake pads are more complicated than the simple hunk of metal they appear to be, and there are a vast array of factors that contribute to their wear characteristics.

Discs

As with pads, gray iron brake discs are far more complex than they initially appear. They use both design features and various ingredients to impact how quickly the discs absorb and shed heat, how easy they are to cut/machine, resist cracking, resist corrosion and abrasion, and generally change and decay over time. Each manufacturer has a proprietary mix and for their iron discs, and some like AP Racing discs have numerous patented design features. Over time and through experience, the 'recipe' for iron brake discs has evolved. AP Racing has been in the motorsport game for a very long time, and have refined their mix across those decades. They look at things like the size of the iron flakes in the discs, how those flakes are arranged to prevent cracking, etc.

In addition to the actual design and material itself, just as much time and thought has gone into the disc production method itself...how the mix is poured, cooled, heat/stress-relieved, final machined, etc.

Please trust me when I tell you that the amount of time that has been spent on the involved chemistry is staggering. I've spoken with engineers at various pad and disc manufacturers over the years on this topic, and honestly, I don't think most of the readers here want them to post anything. You would likely fall asleep at your keyboard. If anyone does want to read more on the technical side, here's an excellent SAE paper that looks in-depth at these topics.

Friction Couple

A complicating factor when considering pad and disc wear is the pad transfer layer. A pad transfer layer occurs when a brake pad is heated to a certain temperature, and the material sticks to the disc face. The goal is to gradually bring the pad to that temperature, and build a transfer layer in a controlled manner. That is accomplished through the bed-in procedure (see our video on that topic here). Just like a tire interacts with the track surface, the pad interacts with disc face. When heated, pad material is constantly being transferred back and forth from the disc face to the pad face.

If you want to get the most life out of your discs, we strongly encourage all of our customers to take advantage of our patented disc bedding/burnishing service. It brings the discs up to operating temperature in a controlled manner, and properly prepares them for heavy use. We have custom, computer-controlled programs for different pad materials. Some pad compounds require more pressure, less time, etc. We burnish discs for pretty much any and all serious pro race teams running AP Racing brakes. We've found that it does positively impact disc longevity. It helps prevent the thermal shock of going out on the track the first time with new discs and blasting them (which can and does lead to severe cracking). It also eliminates the need to waste valuable track sessions fiddling with your discs.

Hopefully that is more helpful than just hand waving ShakeNBake.

JRitt@essex

For a GT4 we would recommend starting with the same pad compound front and rear. On some platforms a staggered mu setup is common. Some people use mu as a tool to adjust feel. For example, I've had customers with time attack Subaru WRX STi's run a higher mu compound in the rear than they have on the front. They do so to try and get the car to rotate under trail-braking, because their car is so ridiculously nose-heavy, particularly under braking on sticky tires when even more weight shifts to the front. On a nicely balanced car like yours, that isn't an issue.

JRitt@essex

Thank you for posting that up! I meant to write that ten years ago, but never got around to it. Hopefully that serves as a good basic guide for all of our J Hook disc customeres.

JRitt@essex

A couple more things...For those of you running AP Racing discs and Ferodo pads, can you please post or email me some pics? If you could include a few words about how you like their performance, that would be even better. For some reason, our Porsche customers are severely underrepresented in our galleries, blog, and social media. You guys have some of the baddest, most desirable cars out there...please share!

Ferodo DSUNO. In addition to the DS1.11 compound, we are now offering the Ferodo DSUNO compound for the GT4. Overall characteristics are very similar to the DS1.11, except the DSUNO has more bite/higher mu. Our customers across all platforms are probably split about 60/40 on DS1.11 and DSUNO. Many have switched from the DS1.11 to the DSUNO and prefer the added bite. One of the best things is that you can switch back and forth between these two compounds without having to fully re-bed your discs. You should still go easy on the pads and bring them up to temp gradually in your first session, but you don't have to do any intricate procedure to get the discs ready for them. The goal is to heat the pads gradually, get the pad faces mated flush with the disc face surface, and slowly start laying some of the new material down over the old.

One of our GT3 customers recently made the switch from DS1.11 to DSUNO on the front and set a track record on them. He is actually running a staggered setup, with the higher mu DSUNO in front. It can work, but it comes down to individual preference/driving style.

ShakeNBake

Great info from someone in the order of the phoenix...(sorry reading harry potter with the kids right now).

Follow on question to clarify what I hear from vendors.

What is an 'Endurance Compound"? I can imagine what it means, but...really, what is it? What formulation changes differentiate it from a sprint pad? Are there generally negative tradeoffs with rotor life?

I will find some pics. I made the switch to DS1.11 pads 2 years ago from PFC08s to see if I could reduce the insane cracking on PFC rotors, piston dust seals disintegrating, and pad material that sometimes decoupled from its backing plate. They have performed about the same in terms of stopping power, have about the same life, but are much more consistent across the time I'm on the track and are much, much nicer to the rotors I've used (PFC, OEM, and now AP). I'm on AP rotors now, it's the 6 th track day, and they still look new - I can't see any cracking, which is a very foreign concept to me, having 6 years of experience with PFC hardware.


I have a recent experience to share that puts a (another) point on why I am so skeptical of vendors saying anything about safety equipment to push it on us wannabe racers.
At COTA this past weekend, I was doing check-rides for students moving up the run-group ranks. A green solo check-ride in a brand new Turbo S went horribly wrong (yes green is what you would think it is, the newbie run group and Chin has the concept of a solo green student). The student had replaced his ceramics (rotors and pads) with an iron Racing BRake.com "track/race" setup. He was told it was the best setup for track use, and if you've seen racing brake's posts, they try to sound knowledgeable and helpful. 3rd lap of the second session of the weekend on these new rotors and pads, the front pads wore completely to their backing plates on passenger's front, and melted through one of the pistons and breached fluid seal on the caliper. This happened when we were braking from 120mph (I capped him at 120) into Turn 12. We started a spin at about 100mph, and continued to spin up to and into the gravel trap. Somehow we didn't hit anything.