Clark-ApexPerformance

I have PMed you a quote for the AP rotors/hats shipping from the US.

When the DSUNO compound pads get here we will be putting some into our inventory.

JRitt@essex

Hey E-Mike...I saw your thread. I'm glad they're doing a proper job for you! Thanks for the purchase.

Below are some examples of our J Hook discs in various degrees of wear. The first stages of use show hints of little heat checks in the center of the disc. It's not uncommon to see these small heat checks after even one day on the track. They are a natural result of the iron expanding and contracting with the massive temperature swings experienced on the track.


Over time those little checks will grow larger and larger as shown below.



More abuse...more checks...



And more...



After enough cycles of expansion and contraction, the surface of the disc looks like a patch of arid ground.




If you see any cracks on the outer edge (OD) and inner edge (ID) where the disc attaches to the hat, then it's definitely time to replace the iron ring. Below is an example of a terminally-cracked disc.



Here's another example with a fracture on the outer edge:



Also remember that there is an inner disc face! Some people only peek through the wheels and look at the outer disc face. That's a no-no. You need to get your head inside the wheel and check the inner disc half (the part not attached to the hat) in case something like this is hiding from plain sight:




Please keep in mind that it's impossible for us to give a firm "yes" or "no" on whether a disc is still usable, safe, etc. There are simply too many factors involved. For example, running three 20 minute sessions in a Miata with a big brake kit installed at Willow Springs is going to produce dramatically less incremental stress on the disc vs. running a single lap in a 991 GT3 RS at Road America.

The responsibility is ultimately on the individual and their mechanic to keep a close watch on the discs. You should really be checking them every time you check your tires or oil when you're at the track (which should be frequently).

My personal advice is to never run a disc (or any component on your car for that matter) that you think is at all marginal, causes you any concern, makes you nervous, etc. Ask yourself if you would put your wife or child in the car for some hot laps with that part installed? If the answer is "no," don't be a knucklehead and tempt fate. It's not worth writing off a $150k car or being injured over a couple hundred dollar disc that is nearing the end of its life. Use your noggin!

Finally, it's never a bad idea to keep a spare set of iron rings and attachment hardware on-hand in your trailer, particular if you've been running your current discs for a while. Iron disc rings don't age like fruit. If you keep them in the oil paper in their original boxes, they can sit in your trailer virtually forever in as-new condition. It's a lot more fun to install a new iron disc ring during lunch than it is to pack up shop, forfeit your entry fee, say goodbye to your friends, and start the long drive home from the track due to a disc failure.

orthojoe

^ awesome post and great words of wisdom!

electron mike

Thanks Jeff, that is exactly what I was looking for!

sasportas

Ferodo pads are working great.

PM me with any questions.

Maxi_z

I just fitted some front and rear ferodo racing ds 1.11 brake pads on the 991 gt3 for a track day

I used some pagid rs29 and rsl1 yellow pads before on the gt3

I did some bedding in of the pads on the street and on the first track session and the performance and consistent braking and pedal feel of the ferodo ds 1.11 is for me really good and maybe slightly better than the pagid endurance pads

But I found the ferodo after the trackday to make a much more "metallic" noise on light braking or sometimes even just withouth braking on the street and found them quite aggressive on the rotors

I did not really expect the ds 1.11 to feel that "metallic" (almost like you would expect from some ferodo racing ds 3000)

any explanation about that?

Thanks

JRitt@essex

Thanks for the feedback on the Ferodo's and glad you're enjoying them! Based on a huge amount of customer feedback, the Ferodo DS1.11's tend to be fairly gentle on discs considering that they are a full race/track pad. I believe what you may be experiencing is the loss of the pad transfer layer on the face of your discs. When you heat the pads up and bed them in, you get a nice transfer layer of pad material on the disc face. That layer typically stays there during a track weekend as the pads are repeatedly heated up to the temperature at which they adhere to the disc face. The discs have a blue-ish gray tint to the swept area. When you leave the track and drive on the street however, the pads never reach the temperature at which they stick to the disc face. Instead, the cold race pads act in an abrasive manner on the disc face, scrubbing the transfer layer off. That leaves the disc with a silver, clean appearance. Below are a couple of videos we did years back on bedding in discs and swapping between street and race compounds. Please watch those, as they illustrate everything I wrote above.

Pad choice is always going to be a compromise to some extent. There is no single pad compound that runs silent on the street, doesn't scrape the discs, and produces no dust...yet can run on the track to 1500F and stop the car all day long without fading. The ingredients required to make a pad silent are not the same as the ingredients to resist fade at searing track temps. The ideal way to achieve optimum performance on both the street and track is to switch pad compounds for each environment, and run a pad that was designed for that environment. That means a track pad for the track, and a street pad for the street. Fortunately, Ferodo makes several pad compounds that share many of the same ingredients, but they have a few tweaks that optimize them for different environments. The three Ferodo pad compounds below can be swapped on the same discs, without requiring a complete bed-in. You just need to get the new pads seated on the discs with a few hard stops once they're in the caliper. That is often not the case when switching between pad manufacturers. For example, if you run an Endless race pad and a PFC street pad, the pad materials and composition will likely be extremely different (I'm just using random manufacturers to illustrate the point). When you try to lay down a pad transfer layer on the disc face, the two materials will get hot, smear together, and essentially contaminate each other. The result is typically a mess of pad material stuck on the disc faces in splotches, which then translates to vibrations, judder, pulsations when you step on the brake pedal. The pad materials simply don't 'play nice' on the disc face. It's like trying to mix water and oil.

That is not the case with the Ferodo materials below. They have the same core ingredients, with other constituent ingredients in varying proportions. As such, they can be laid down together on a disc face without all of the nasty side-effects. For a dual-use street/track car, the ideal situation is to run the DS2500 on the street/autoX/weekend drives, and save the DS1.11 and DSUNO for the racetrack. That will give you optimized performance in each environment. The DS2500's will be lower noise, good cold bite, and easy on discs on the street. When you go to the track, the DS1.11 and DSUNO will give you good hot bite, and a high temperature threshold before they fade.

Obviously, constantly swapping pads is a pain in ****, particularly if you go to the track frequently. On the GT3, it's especially a hassle because of the center-locks, the one-piece caliper that must be removed to swap pads, and the hard brake lines. If you don't want to break out your four foot breaker bar every weekend, you'll need to compromise. For some cars, that could mean running the DS2500 at all times, and not pushing them beyond their max operating temperature (which is considerably lower than the temperature threshold of the DS1.11 and DSUNO). On the GT3, that is not advisable however. While you could probably squeeze some laps out of them on a fairly easy braking track with street tires, they would burn up quickly. The DS2500 is a better track compound for something lighter and slower like a Miata or BRZ/FR-S. That means that if you want a 'do it all' pad on the GT3 that you won't be swapping out, the DS1.11 would be the best option. Again though, when you wear the transfer layer off of the discs, you're going to have to live with a little scraping and squealing.

On my personal track cars over the years, I always start out with the best intentions of swapping between street and track pads before and after every track event. Inevitably, I decide it's too much hassle, and I drive around with squeaky brakes. A couple years ago one of my neighbors actually said, "Your brakes are broken...aren't brakes what you do for a living?!?!" Once that pad transfer layer wears off, the noises and disc wear are going to increase. There's really no way around it, and that will be the case with ANY track/race pad compound from any manufacturer.

Again, it's all going to boil down to a bit of compromise. It's no different than any trying to run any other automotive component on the street and track. If you run a halo seat, it will protect your head but limit visibility on the street. If you run race slicks, they'll grip great at the track but will be useless in the rain. If you run an ultra-stiff suspension, it will increase your cornering speeds but rattle your teeth out of your head over potholes in the street. If you run a big lumpy camshaft, it gives you great top-end power but stutters on off-idle street driving.

Hopefully the above all makes sense. Please let us know what other questions you have.

Here are the videos. Most of our customers find them quite helpful in understanding the different friction mechanisms, etc. I filmed these on my C5 Z06 about 8 or 9 years ago. You can see some other educational brake videos on our Essex YouTube page: https://www.youtube.com/channel/UC-n...LpTBXW_IT3tzOQ

Ferodo Pad Compounds:
DS1.11- The DS1.11 is one of Ferodo Racing's latest endurance race pad offerings. It has slightly less bite at high temps. vs their older DS3000, but doesn't decompose nearly as quickly under extended heavy use on the track. The DS1.11 is known for its extremely flat torque curve, which means that as temperatures go up, the response through the brake pedal remains consistent. The DS1.11 can be thrashed all day without having it burn up or fade, it's easy on discs, and doesn't have many of the judder or vibration issues that competing products have. If you want an extremely solid, all around race pad that will perform well and last a long time, the DS1.11 is the perfect choice.

DS2500- Although we always recommend using a dedicated race pad for the track, the DS2500 is one of the best hybrid street/track pads on the market. It features the moderately high bite and solid fade resistance of a track pad, with the relatively low dust and noise levels of a street pad. When used as a street pad, it can produce some squeal on certain vehicle platforms. During aggressive driving the DS2500 is known for its flat torque curve, which means as temperatures go up, the response through the brake pedal remains consistent. If you drive aggressively on the street, do some canyon runs, autoX, and maybe some light track duty on street tires, the DS2500 is tough to beat.

When used on high HP, heavier cars (2,800 lbs+) on the track with race tires, pad wear rates tend to be higher than on Ferodo Racing's other pad compounds. Under those conditions, Essex would recommend the Ferodo DS1.11 or DSUNO.

DSUNO- Ferodo Racing has made great strides in pad development over the past few years, and DSUNO is their latest offering. For our customers who enjoy the performance of the DS1.11, but just want a little more bite, we recommend the DSUNO. It doesn't wear quite as long as the DS1.11, but it does offer a higher overall mu once it reaches track temperatures.

thebishman

Maxi_z

Hello Jeff

Thanks a lot for the really professional and detailed answer

I think that you are right what probably happened is that for some reason I did not get a proper layer of pad material transferred on the rotors

They got some not nice kind of wear similar to when you make a few miles with a pad completely worn and they do not have that usual blueish color on the rotor

I did a few medium power but long stops to bed the brakes maybe from 150km/h to 50km/h and then parked the car and then before the trackday I also did a few more but probably not enough

Also it was a cold and humid day maybe it somehow made things worst

Some times with pagid pads I think I overdid the bedding in and reached too high temps so I tried to be a little more gentle when bedding in the ferodo but probably too gentle

I will try to do another bedding procedure and let you know as I agree that the ds 1.11 should be one of the best pads for the price and use on the gt3 for all of the reasons listed above

JRitt@essex

No worries, and glad we could help! Bedding the discs/pads is definitely a bit of a black art. It's just something that you get a feel for after doing it a million times. The big problem is that every pad compound is going to be a bit different in terms of its bedding requirements. A street pad needs relatively little heat in it to start sticking to the disc, whereas some race pads need to get extremely hot by comparison. That makes it challenging, because one bedding method won't necessarily be a 'one-size fits all' solution. Your starting speed will vary a bit, as will the length of your stop, and how quickly you spin back up to your starting speed. Those variables all change how much and how quickly you're converting all of that spinning disc energy into heat. The other variable is that the initial bed-in on pads is a bit different than subsequent ones. That makes it even more challenging to get it right! It's definitely one of those things that is a bit trial and error. Feel free at any time to contact us if you have any other questions.

Thanks Bishman!

Maxi_z

I just did some bedding again

I did a few easy brakings from 80km/h then I did maybe 20 or more higer speed brakings with medium pressure from moe than 130km/h to around 20km/h and even a few with higher pressure

then I did a little bit of road without braking to cool down

It s very slighly better but still the pads are making the noise similar to a worn out pad on the metal

I took a picture of the front brakes and they look a little more blueish but not uniform and probably as now they are not smooth anymore they got to do much more road but let me know if it could be that I overheated the pads too fast without enough bedding before the trackday or if now that the disc surface is not perfect there is something I could do to meke them better

Other than that they are braking very well and do not overheat or fade at all

The brake rotors are almost new and they just did a few sessions on a trackday with the ferodo pads and the weather was a little cold and the track is not too big with many medium speed but hard brakings

Thanks

Maxi_z

I just did a second trackday at the same track and the pads continue to perform really well on track but as soon as I am at normal road speed and light braking there is still that abrasive noise

Do you think that because of the initial rotor wear due to maybe not perfect bedding now it s too late and the pad material wont properly stay on the rotor or do you think it just takes more miles and time?

Thanks

JRitt@essex

I don't see anything concerning at all in the pic you posted. The discs actually look very good, and the pad material appears fairly uniform to me. With the drill holes in the disc, you're not going to get the smooth, even transfer layer that you would with a plain face or slotted disc.

Problems with pad transfer layers do not look like the pic you posted. Problems usually appear as spots or splotches, or the outline of the actual pad shape. That occurs when you overheat the material, and it sticks in a big glob on the disc. You'll know for sure when that happens, because you'll feel judder and vibrations when you hit the brake pedal, every time the pad makes contact with the high spots on the disc. There is no evidence of that issue on your discs.

Racing pads can remain noisy on the street, no matter what you do with them. Their very nature (that they can handle high track temps) more or less guarantees that they are going to be more abrasive than a street pad. Most of the time when driven cold, the DS1.11 is going to make some noise. It's more rare that they're silent. If you want near-silent performance, your best bet is to swap to the Ferodo DS2500 for street/autoX use.:

Ferodo DS2500 front 991 GT3: https://www.essexparts.com/ferodo-ds2500-brake-pads743

Ferodo DS2500 rear 991 GT3: https://www.essexparts.com/ferodo-ds2500-brake-pads745

Here's a good example of uneven pad deposits that I found:


Hopefully the above makes sense. Race pads aren't supposed to be quiet and gentle on discs when cold. That's not what they are designed to do. Race pads on the street is a compromise, just like race tires or a racing suspension on the street.

Mech33

Hi Jeff, do you guys offer the new DS3.12 compound available in the OEM 991.2 GT3 front and rear caliper sizes yet? Thanks.

JRitt@essex

Yes, we have them front and rear for the 991.1 and 991.2 GT3, GT3 RS, GT2 RS, and Cayman GT4. A small batch just arrived late last week. They aren't up on the website yet, but we do have some. Thanks!