JRitt@essex

We typically keep quite a few AP Racing J Hooks on the shelf at all times, so no issues about having them available locally. We typically ship spare iron the same day, and assembled discs/hats within 24 hours. Our burnishing/bedding machine also runs all day, five days per week via a dedicated technician. We also hold a sizeable inventory of Ferodo DS2500, DS1.11, and DS3.12 on the shelf. The pic below shows only one row of our inventory (I just snapped that pic in our warehouse). Every yellow and blue box you see is AP Racing.

JRitt@essex

Thanks for the feedback on the DS3.12 gents. Please keep it coming. We have quite a few sets out there now, and the response has been overwhelmingly positive across all platforms!

JRitt@essex

For those who did not see my comments on the Ferodo DS3.12 in another post, here they are:

Coefficient of Friction and Maximum Operating Temperature

Any time you rub two objects against each other friction is generated. In this case we're rubbing a semi-metallic brake pad against a spinning iron disc. Mu μ {\displaystyle \mu } refers to the coefficient of friction of the pad compound. In simple terms, that means the amount of friction that exists between the brake pads and disc. The mu value for most brake pads falls within the 0.3 to 0.6 range. The closer a pad's mu value is to zero, the less friction exists between the pad and disc. Pads with a low coefficient of friction are often described as feeling wooden, not having much bite or grab, or the driver feels like they must press the brake pedal with a lot of force to get the car to slow. Conversely, a pad with a mu value closer to one feels like it doesn’t require as much leg effort for the pad to 'bite' into the disc and slow the car. If the mu is too high however, the brakes may feel like a light switch. They’re either on or off, and difficult to control with varied pedal pressure (modulation). Breathing on them lightly or trail braking could prove difficult. The best pad compounds hit a sweet spot in terms of balancing pedal pressure and controllability.

What makes mu both interesting and complicated is that it changes constantly with temperature. The Holy Grail of brake pads would be a compound that has a perfectly flat mu curve across the entire temperature range from zero degrees to the highest temperature the pad would ever reach (for the typical HPDE driver or club racer that is approximately 1400°F). Such a pad would exhibit a linear response through the brake pedal, regardless of where and how it was being driven. From the driver’s perspective, that would mean every time they pressed the brake pedal with the same amount of force, the car would feel as if it slowed at the same rate. That consistent feedback loop would allow the driver to dial in their brain and leg to precisely control the car’s response. Each time they approached a turn, they would feel confident about how the car was going to react when they stepped on the brake pedal. When trying to shave a tenth of a second at every turn, one can imagine how valuable that would be!

Unfortunately, most pad materials have a narrow temperature window in which they generate a given amount of mu. Depending on the pad’s constituent materials, that temperature window may be what you experience when driving to the grocery store (street pads optimized for low temps), or it may be the temperatures you experience on Lap 6 at Watkins Glen (race pads optimized for high temps). To this day, no pad material exists that generates the same mu across its entire operating temperature range.

Pads also have a maximum operating temperature, which is the highest temperature at which the material can still generate friction. At some elevated temperature, any given pad is going to start burning more quickly, melting, vaporizing, etc. At that point it can no longer generate any friction on the disc face, and its mu tapers towards zero. Even though the brake pedal may still feel firm, the car doesn’t slow because very little friction is being generated between the pad and disc. That is what is referred to as pad fade. In these situations, the pad can also stick to the disc face in globs, smear, and create high spots that cause judder and vibration. We frequently see this when people drive street pads on the racetrack, because street pads have a lower maximum operating temperature than race pads and are not optimized to generate mu at track temps. What is particularly scary about some street pads, is that once they approach their maximum operating temperature their mu falls off a cliff and rapidly approaches zero. In real world terms, that means the driver doesn’t receive any warning. On one stop the car slows as expected, and on the next the pedal stays hard but the car doesn’t slow.

With a typical race pad, mu is low when the pad material is cold. If you push hard on the brake pedal, it doesn't feel as if the pads are gripping the brake disc very hard. Many people refer to this pad attribute as its 'cold bite'. As the disc and pad temperatures rise however, mu increases, and the driver doesn’t have to press very hard for them to grab the brake disc. Track pads also have more gradually tapering mu when temperatures get extremely high, which means they give more warning as they approach their max operating temperature.

Looking at a Brake Dyno Plot

The first thing to consider when looking at a brake dyno graph is that all brake dynamometers are different. One can view this situation exactly like engine dynos. The mu numbers one manufacturer claims or generates on their dyno aren’t comparable to the numbers generated by another manufacturer. The machines are different and the test parameters are different: number of brake events, different stop durations, different amount of time between stops, different caliper pressures, etc. We constantly see people on the forums comparing mu values across pad manufacturers but doing so is futile. A Pagid pad that Pagid claims has a mu of 0.5 at 1000°F is not the same as a Ferodo pad that Ferodo claims has a mu of 0.5 at 1000°F. No comparative conclusions can be drawn from looking at mu graphs from different manufacturers. The only value of a manufacturer’s brake dyno graph is to compare within that manufacturer’s line of brake pads (assuming the same procedures and machine were used to produce the results for all data on that graph). For example, comparing the Ferodo DS2500 to the DS3.12 on a Ferodo dyno plot is a valid comparison. The specific numbers are essentially irrelevant since you can’t compare them to other brands (unless you have your own brake dyno), but the shape of the curve and relative differences between the Ferodo pad compounds does provide valuable information. Again, ignore the actual numbers and focus on the relative differences and the shape of the curves.

The above is one of the reasons why Essex built our own brake dyno, so we can do comparative testing both for ourselves and for our race team customers. We can conduct apples-to-apples pad tests, and we know what we have before its ever run on a car. We also don’t have to blindly accept a manufacturer’s data. We find out on our own what we have, and how it compares to other available products that we’ve tested on our dyno via our own procedures.

On to the dyno graph! The dyno below was provided by Ferodo, but we’ve seen similar relative results on our own Essex brake dyno. The value in this graph is the relative differences across the Ferodo compounds. If we look at the new DS3.12 plot, we see that it has higher mu across the board from stone cold to searing hot vs. any prior Ferodo compound. That means the DS3.12 is always going to feel as if it requires less pedal effort vs. the DS1.11, regardless of whether you’re on your morning commute or driving a session at Road America. With the DS3.12 you won’t have to press the pedal as hard to slow the car.

What’s shocking about the DS3.12 is that it exhibits almost no variation in mu across an amazingly wide temperature range. Out of all the pad compounds we’ve ever tested, from all manufacturers, the DS3.12 shows the flattest torque curve across the broadest temperature range. On track, most of our customers will be running their pads in the 700-1400°F range (400-750°C). Across that range, the mu curve for DS3.12 is table-top flat. That means that on every turn, on every track you drive, on every lap, your brake pedal is going to feel almost exactly the same, providing tremendous consistency and repeatability.

What we also noted on our dyno about the DS3.12 that cannot be seen on the dyno graph, is the compound’s response to varying pressures. When we test a pad we vary the clamp load on the pad and disc. The DS3.12 shows an amazingly linear response to varying pressures, which is not the case for many other pad compounds we’ve tested over the years.

If you look at the DS1.11 plot, you can see that it responds a bit differently vs. the DS3.12. As temperature rises, mu tapers off gradually. What that feels like as you go deeper into a brake event, is that you must press a little harder on the pedal to get the desired response from the pad. Some people like having to press harder, because it feels natural to them. Others don’t and prefer a more linear pressure throughout the entire stop, which is what the DS3.12 offers. There is no good or bad in this case, and the feel you prefer is completely a matter of personal preference.

In summary, the DS3.12’s incredibly flat torque curve and linear response to varying pressures both contribute to a tremendous amount of control. Once you calibrate your brain and leg to the DS3.12’s higher mu level, which requires less leg pressure, it should be the ultimate pad for threshold braking while controlling ABS intervention. Given our aggregate dyno data, the data Ferodo has collected from racecars in Europe, and our own field testing here in the USA, we believe the DS3.12 may be a homerun for many of our customers. As a bonus, we also have evidence from some tests that indicates the DS3.12 could last up to 20% longer than the DS1.11 under certain conditions, further enhancing its desirability. We’ll see how that plays out in the field, but we are extremely excited about this pad. It is a truly world-class compound that achieves some things we have never seen before.

Frenchboy

Thanks to Essex for the detailed description. Super interesting. I currently run DS1.11 on a AP Racing Pro 5000R kit and am interested in the DS3.12 compound. Sent you guys a couple of emails this week asking about this. Haven't heard back from you guys so I am assuming you are extremely busy...
Two additional questions to your :
1. What are the Ferodo Pads part numbers, front and rear, for the DS3.12 that fit my AP kit?
2. Since the coefficient of friction is higher with the DS3.12, I am assuming the rotor life is decreased as compared to the DS1.11. How would you describe the disc friendliness of the DS3.12 compound? Similar to, marginally worse or much worse than DS1.11

JRitt@essex

To what address did you send your email? We are extremely busy, but our sales staff typically get back to customers within hours, and we have two people constantly monitoring the generic sales email. I definitely want to find out what the delay was. Also, we are open M-F, 8am-5pm ET, and we always have a live human answer the phone during those hours (704-824- six zero three zero).

The DS3.12 part numbers for our 991 GT3 brake kit are:
FRP3144G (front)
FRP216G (rear)

We don't have these on our website yet, as we haven't even done an official launch on the compound yet.

For the OEM 991 GT3 calipers, the part numbers are:
FCP4664G
FCP4665G

In terms of disc wear, there is no free lunch as you note. Yes, the DS1.11 will be a little more aggressive on discs than the DS1.11. I would characterize them as 'marginally harder'. That difference will mainly show itself when the pads are cold. I've been running them on my vette around town cold, and they are putting out a bit more dust (which is mostly disc material) than the DS1.11. You aren't going to see any major difference if you are primarily running them on track. If you're tracking your car, you're still going to crack the discs before you wear them thin. Also, the DS3.12 is still far easier on discs and easier to bed-in than competing brands (just like the DS1.11). It's all relative, and the entire Ferodo DS line doesn't eat discs like some of the competing options out there.

Thanks, and please let me know on that email situation so I can make sure we are maintaining the appropriate level of service. Thanks!

Frenchboy

Hi Jeff, thanks for the reply. I will be ordering new pads for my kit (either DS1.11 or 3.12) shortly. BTW, I have a 2018 GT3 which is primarily a track car.

The 2 emails I sent were to SUPPORT@essexparts.com. One on 5/22 and one on 5/24. PM me if you want more info. Thanks much!

disden

Essex hooked me up with AP Rotors and Ferodo 3.12; after 2 days at NCM and 2 days at MidOhio can say that I am very pleased. Fantastic brake feel, incredible stopping power vs stock setup. I am not a massive stand on the brakes person, I try to use them more to help pitch the car, but I found my braking distances to be much shorter and more precise. My lap times decreased because I was able to drive in so much deeper. I'm sold!

JRitt@essex

Excellent! I just popped on Rennlist to check out what's happening and saw this. We're glad your new brakes are working well for you! Do you have any pics that you could share? Thanks so much, and have fun with your new toys!

sasportas

Just an update.

I've used a set of DS3.12 over the course of 5 track days with out any detectable loss of brake pedal "feel" or fad. Again, this remains consistent over a typical 25 minute DE run.

Interestingly, the rotor face is very smooth without any ridges forming as had been the case with the DS1.11's.

JRitt@essex

Thanks for the input gents!

PorscheRuminator

Great info JRitt

You discussed that in order to compare the mu of different pads they must be tested in the same manner on the same brake dyno. Since you have your own dyno are you able to also give the mu and graphs for the other pads Essex sells? I use Essex-supplied Race Technologies RE10 pads but when they are done I may try the new Ferodo compound. Being able to translate what I feel with my current pads with your dyno plot would be useful.

JRitt@essex

We actually don't offer RT/Brembo branded pads.

We only compare brands internally. We've discussed publicly sharing dyno data, but there are some commercial issues involved, so we haven't done so.

Randyc151

Any more field updates on this? I just installed another set of DS1.11, but I'd love to have more feedback on the DS3.12 from anybody tracking these pads on Porsche. Of special interest, how do these pads feel at the end of long straights vs DS1.11? Secondarily, how's the general squealing around town?

Mech33

Loving the DS3.12 so far. Some squeal around town, maybe slightly less the DS1.11.

erko1905

Availability isn't fantastic - I believe the rears are on back order so I had to get 3.12 front 1.11 rears very recently.

Other than that, it seems to be incrementally better than 1.11 in every area: slightly higher friction, great pedal feel, easy modulation, wears longer than 1.11, less noisy than 1.11. I'm guessing rotor wear must be worse.