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We have located a 991.2 GTS and a 991.2 T that we will be test fitting for our complete front and rear AP Racing Radi-CAL brake system. We hope to do so within the next couple of weeks. Thanks for your patience!
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'09 Carrera 2S, '08 Boxster LE (orange), '91 Acura NSX, Tesla Model 3 Performance, Fiesta ST
Jeff Ritter
Mgr. High Performance Division, Essex Parts Services Essex Designed AP Racing Radi-CAL Competition Brake Kits & 2-piece J Hook Discs Ferodo Racing Brake Pads Spiegler Stainless Steel Brake Lines
704-824-6030 jeff.ritter@essexparts.com
Does the GTS have centre lock wheels? I don't think it matters. Because there are five locator nubs that screw in the same place as 5 stud. So from what I have seen, the hats are the same for a 5 stud or centre lock.
Does the GTS have centre lock wheels? I don't think it matters. Because there are five locator nubs that screw in the same place as 5 stud. So from what I have seen, the hats are the same for a 5 stud or centre lock.
Can you confirm?
Yes, the GTS has centre lock, and yes our discs for both the centre lock and the five lug will be the same.
Is the kit for the 991.2 GTS different to the one for the GT3's in the picture? Also will the GTS run a different shape pad? Different to the GT3, and or different shape to OEM pad? What size did we end up with for a BBK for the GTS? Thanks.
Is the kit for the 991.2 GTS different to the one for the GT3's in the picture? Also will the GTS run a different shape pad? Different to the GT3, and or different shape to OEM pad? What size did we end up with for a BBK for the GTS? Thanks.
The disc sizes for the GTS will be a little smaller than the GT3 Kit.
OEM front GTS= 350mm
Essex/AP front GTS= 372mm
Essex/AP front GT3= 394mm
Pad shapes for our brake kits are different than the OEM calipers. The front pad shape in our GT3 and GTS kits will be the same. Our rear pad shape for the GT3 and GTS will be slightly different.
Thanks for the great information. I know its not your fault, so I'm not busting your *****, but someone needs their ***** busted for this.
A Stock GT3 has 380 / 380 your upgrade for them is 394 / 380
A stock GTS ha 350 / 330 your upgrade is 372 / 365 (Crazy numbers to remember)
My problem is, my car has a lot more power than a GT3 and GT3-RS. You want me to pay BBK money for an upgrade that still does not get upto the Stock 380 / 380 of a GT3.
The very least AP could have done would be put the rear 380 J-Hook of the GT3 on the Front of the GTS. Rather than a 372. Imagine at a car meet, or the track. Oh Wow man you have J-Hooks. What size are they? Oh 372 front and 365 Rear. WTF!!
Just saying. Brembo GTS has a 380 / 380 GTS upgrade for the GTS. Why on earth would I even consider AP 372 / 365?
Thanks for the great information. I know its not your fault, so I'm not busting your *****, but someone needs their ***** busted for this.
A Stock GT3 has 380 / 380 your upgrade for them is 394 / 380
A stock GTS ha 350 / 330 your upgrade is 372 / 365 (Crazy numbers to remember)
My problem is, my car has a lot more power than a GT3 and GT3-RS. You want me to pay BBK money for an upgrade that still does not get upto the Stock 380 / 380 of a GT3.
The very least AP could have done would be put the rear 380 J-Hook of the GT3 on the Front of the GTS. Rather than a 372. Imagine at a car meet, or the track. Oh Wow man you have J-Hooks. What size are they? Oh 372 front and 365 Rear. WTF!!
Just saying. Brembo GTS has a 380 / 380 GTS upgrade for the GTS. Why on earth would I even consider AP 372 / 365?
Actually, it is my ***** that are being busted. Essex decides on what size discs to use in our brake kits, and we do so based on a tremendous amount of experience. The odd sizes (372mm and 365mm) were chosen specifically based around needs. We could have went with a generic 380mm setup, but 380mm is much, much harder to stuff inside 18" wheels in most cases, which is what the wheel size that many of our most popular applications run. When we drew up the specifications for these discs, we looked at what we needed, and didn't just follow an industry trend or what everyone else has done in the past.
As I wrote in my disc thread, we approach to a new application is need-based. In terms of disc size, that means "How much thermal mass do the front and rear discs require on this particular chassis, assuming a typical level of car modification and usage environment?" Our anticipated usage profile would be something resembling: HPDE enthusiast or club racer running slicks, suspension modifications, aero, weight reduction, and +100 horsepower (or something along those lines), running four 20-40 minute sessions per day.
Also as noted in my other disc thread, our 372mm disc is going to outperform the OEM GT3 disc in every imaginable way. Racing disc design is about efficiency and leveraging technology, not just about size. Anything larger than is absolutely necessary is dead unsprung weight to drag around. Why would one want a 380mm disc if a 372mm disc gets the job done, doesn't fade, weighs less, fits more wheels, and costs less? (disc casting costs typically increase with size)
In terms of what our front 372mm disc can handle, it will absolutely handle anything any 991 can throw at it. For example, we have many, many heavily modified Corvettes running our 372mm front disc, and it works beautifully for them. The typical track-modded C7 Z06 or ZR1 weighs about 3500 lbs. and has at least 700 horsepower. Some of our customers have up to 1000 HP. They also run huge slicks, have excellent aero, and they are considerably harder on front brakes than a 911 (of any trim level, due to the drivetrain layout).
At the last Corvette event we attended last summer, there were a dozen or more of them there running our 372mm front kit. There wasn't a whiff of brake fade or complaint from any of them. Quite the opposite in fact. They were gushing about our brake kit's performance...click here to see pics: https://www.essexparts.com/news-blog...orvette-museum
Our systems aren't designed for bench-racing or water cooler bragging rights. Our systems are for superior performance. If the numbers seem out of the ordinary, that's because thought has gone into every design detail. We don't just follow a recipe and churn out new applications. We have lots of serious machinery out there with this setup, and we have won all sorts of races and championships with them. It's highly improbable that any 991 is going to be that much harder on their brakes than any of these examples. You can see them on our blog: https://www.essexparts.com/news-blog
Below are some more links to satisfied customers running our 372mm/365mm systems. I'll use a lot of Corvettes as my examples, because they are heavy, fast, and devour front brakes like just about nothing else short of a Nissan GT-R:
As another data point, here's a customer winning the NASA championships on our considerably smaller 355mm system on his vette...tell me this guy isn't running hard on the brakes! https://www.essexparts.com/news-blog...p-video-inside
Here's a different vette nabbing a podium with our smaller 355mm front setup at Cal Speedway: https://www.essexparts.com/news-blog...driving-c5-z06
That same driver later checked in with us after racing for three years on our 355mm setup without a single caliper rebuild. During that time he collected 14 race wins and 25 podiums. Depending on the series he was running, his car weighed between 3,250-3,450 lbs., and put down between 400-430 RWHP. Again, he was running our smaller 355x32mm front discs. https://www.essexparts.com/news-blog...a-and-trans-am
Finally, the ONLY reason we went any larger on the 991 GT3 is because we had to do so. If you read our thread on that system, I admit in it that the 394mm/380mm discs are larger than ideal. Due to the OEM design and disc size, we had to push the front caliper out away from the hub to squeeze in an adapter bracket, hence the larger front disc size. Our 372/365mm setup would have been better suited to the needs of the car, and would have saved more unsprung weight.
In summary, it's not about numbers on paper. It's about design, efficiency, and knowledge on what works. Our systems have won countless races and championships, from Le Mans to autoXing. We know what works on each application, and that's what we design and build. The Porsche 911 uses considerably less front brake than a Corvette, Mustang, etc. Our 372mm (and smaller 355mm and 325mm) systems have proven incredibly capable and durable on those platforms, and there certainly shouldn't be any concerns about their capability on the 911 chassis. Bigger is not better. The bragging point our customers have at the track is, "Wow, it's amazing how much deeper I can go into every brake zone, even though my brake setup is smaller and lighter than those big ugly things on your car." They're also not the ones lying on the scalding hot pavement bleeding brakes and changing pads between sessions.
Thanks for the great information. I know its not your fault, so I'm not busting your *****, but someone needs their ***** busted for this.
A Stock GT3 has 380 / 380 your upgrade for them is 394 / 380
A stock GTS ha 350 / 330 your upgrade is 372 / 365 (Crazy numbers to remember)
My problem is, my car has a lot more power than a GT3 and GT3-RS. You want me to pay BBK money for an upgrade that still does not get upto the Stock 380 / 380 of a GT3.
The very least AP could have done would be put the rear 380 J-Hook of the GT3 on the Front of the GTS. Rather than a 372. Imagine at a car meet, or the track. Oh Wow man you have J-Hooks. What size are they? Oh 372 front and 365 Rear. WTF!!
Just saying. Brembo GTS has a 380 / 380 GTS upgrade for the GTS. Why on earth would I even consider AP 372 / 365?
4 Point 0,
You have to get rid of the idea that bigger is better when it comes to brakes. Don't get stuck on that. Essex already tried to explain this to you in their other thread.
Car manufactures put huge calipers and discs on their cars for marketing. They know that this what people think they want. In fact, you are actually putting on an unnecessarily heavy part on your car when a smaller lighter setup would be more than sufficient. In addition, this allows you to run smaller wheels on the track. Not that you can run anything smaller than a 19" on our cars.
The Essex/AP kits are strictly built for performance in mind. If all you care about is comparing and showing off you brakes with someone else, then I suggest you go with an 8 piston 406mm Rotora kit or stick with the big Brembo kits. They have several options for these cars. Sure, the Brembo GT-R system is a track/performance orientated kit might be comparable to what Essex is offering but it's at a higher cost. If you want the best track setup, then stop worrying about disc size and get the Essex kit.
Last edited by Tay101; 02-26-2019 at 12:09 PM.
Reason: changed sentence
I get the whole more vanes and lighter is better. The thing I also get is you guys want t run 18's. Winter snow tyres etc. I have centre locks. I don't even know if they do a centre lock 18? I also get an aftermarket 350 would most likely perform better than a OEM 380.
I'm fine running 20 inch Cup2 and TrofeoR at the track for drive there and home convenience.
I like the look of 20's but 20's create a huge gap. When parked beside a GT3 and a touring (410 PCCB) my brakes look tiny. The side profiles of the cars are the same, its the huge brakes filling the 20's that make those cars look better. I don't want 405 or 410. 380 is plenty. I certainly don't want 8 pot brakes. I doubt I would see a difference between 372 and 380 lol. But rear 365 maybe. Odd size rotors will be a pain in the butt for pad selection. I bet pads are limited? What pads are available for those size rotors? A full selection like a standard size of 380?
I get the whole more vanes and lighter is better. The thing I also get is you guys want t run 18's. Winter snow tyres etc. I have centre locks. I don't even know if they do a centre lock 18? I also get an aftermarket 350 would most likely perform better than a OEM 380.
I'm fine running 20 inch Cup2 and TrofeoR at the track for drive there and home convenience.
I like the look of 20's but 20's create a huge gap. When parked beside a GT3 and a touring (410 PCCB) my brakes look tiny. The side profiles of the cars are the same, its the huge brakes filling the 20's that make those cars look better. I don't want 405 or 410. 380 is plenty. I certainly don't want 8 pot brakes. I doubt I would see a difference between 372 and 380 lol. But rear 365 maybe.
When installed on the car, you'd never know the difference between a 372mm vs. 380mm disc, but your wheels sure will! When comparing disc sizes visually, you'll only notice the difference in the disc's radius, not diameter. In other words, the 380mm disc is 8mm larger in diameter than the 372mm, but it only sticks out 4mm further from the center of your hub. That's only a 16th of an inch, which is visually indistinguishable.
Odd size rotors will be a pain in the butt for pad selection. I bet pads are limited? What pads are available for those size rotors? A full selection like a standard size of 380?
The disc sizes have nothing to do with pad selection in this case. There are far more pad options for the AP Racing calipers than there are in the OEM shapes. The pads shapes used in the AP calipers have been around for decades, and every major manufacturer has them in most of their compounds. Also, they will potentially be cheaper than the OEM shapes (varies by manufacturer). I'd strongly encourage you to click the two links above and do some reading. Our website has far more info on our products than anyone else offers.Details on the front pad shape are below, although the formatting gets a bit munched when pasting from our site:
Brake Pads in A Commonly Available Shape
The basic pad shapes for the Pro5000R calipers were created by AP Racing many years ago, and are used by a wide range of racing calipers today. They're available in just about every popular racing compound on the market. That means you’ll never end up in a pinch without pads.
Pad Thickness, CP9661 caliper (18mm) Please note that the pad shape we use in our caliper is available in a variety of radial depths (heights), and that Essex recommends the 54mm radial depth version. Another common radial depth in this pad shape is 51mm. The 51mm depth pads will fit into our caliper, but you will be leaving an unswept 'ring' around the disc near the attachment points to the hat (the pad will not hang as low in the caliper). Leaving a portion of the disc face unswept can create a temperature differential across the face of the disc, and doing so could lead to premature disc cracking.The available pad compounds that Essex sells for the CP9661 caliper can be found below. Please keep in mind that there are many other compounds available on the market from other manufacturers. The list below represents only what Essex sells. Underneath the manufacturer list below, the pad compounds are listed from most aggressive to least aggressive.
Pad Cross Reference
We do not sell most of the brands listed below, and Essex cannot guarantee the fitment of those pads in the AP Racing CP9661 caliper. Based on our research however, we believe that these are the appropriate cross references for the basic shape. However, you should verify with either the manufacturer or your installer prior to purchasing any of them for use in the Pro5000R calipers.
We have also confirmed that the complete front and rear brake kits above will also fit the 991.1 GTS.
Next up we'll be verifying fitment on a 991.2 Carrera T. We're 99% sure our discs and complete kits will bolt right onto those, but we'll need a billet spacer for the two-piece disc kit since the OEM discs on the T are a bit smaller. Thanks again for your patience and stay tuned.
Our Spiegler Stainless Steel Brake Lines will fit ALL 991.1 and 991.2 Trim levels and options:
Do you guys think your Kit will fit a 991.1 Base model w/ 20" Wheels? I'm assuming whatever you do to make it fit the 991.2 T/Base will mean it fits on the 991.1 Base as well.
Do you guys think your Kit will fit a 991.1 Base model w/ 20" Wheels? I'm assuming whatever you do to make it fit the 991.2 T/Base will mean it fits on the 991.1 Base as well.
Based on what we know, yes, we believe our complete front/rear brake kit will fit perfectly on the 991.1 Base. That said, we have not test fit our kit on that specific model. As such, we can't yet recommend it on that model. If you're interested in potentially helping us with that however, please shoot me a PM and we can discuss. Thanks!
Just yesterday we received a really nice review from one of our 997 GTS customers regarding our complete Competition Brake Kit. You can see both our front and rear kit in this link.
He's been pounding on them at Sebring on his 997 GTS. The kit on his car is identical to our 991 kit, so his comments offer great insight into the performance potential. You can see his full review in this thread in the 997 section here on Rennlist:
I’ve had the Essex / AP Racing Radi-CAL Competition Brake Kit (Part #s 13.01.10096 front / 13.01.10097 rear) on the car now for long enough to wear out two sets of pads and one set of rotors so it seems like a good time to share my experience for anyone considering the upgrade.
Short version: if you track your 997 and are running in an advanced group or are looking to move up to the advanced group, call Jeff and make the purchase. You’ll love the package!
Longer (much) version: Impressions after 473 laps around 3.7 mile Sebring International Raceway over 14 track days running in Chin Red Group and at David Murry Track Day events plus approximately 3k road miles (mostly to & from Sebring):
They’re the ****!! (my over exuberant response to Jeff’s inquiry sometime during the first day at SIR).
Previous setup was OEM calipers, 350mm Girodiscs and either RE10 or DS1.11 pads. Never had any fade or performance issues, even in the searing Central Florida heat running mid to high 2:20s lap times. I was very pleased with the setup and found myself gaining track position into and out of corners on higher horsepower cars that smoked me on the long back straight.
As I got quicker though, pads and disc life dropped significantly, and caliper rebuilds added to the escalating consumable costs. The higher costs and the desire for improved brake modulation started me on the path toward a brake upgrade for the GTS. The vast number of race cars with AP Racing brakes I saw while walking the Sebring 12 Hour paddock in 2018 led me to investigate AP which in turn led me to Essex Parts Services.
I had been buying pads and discs from Clark at Apex for years and value his input greatly. He had nothing but great things to say about the Essex / AP kits so I contacted Jeff Ritter and went from there. The kit is extremely well engineered and built. The tech at Champion Motorsport that did my install said it was a breeze and that everything fit fine.
First set of pads was the Ferodo DS1.11. I followed Essex’s bedding instructions to the T and headed for Sebring. Brought them up to temperature gradually during the first laps of the first morning session as Jeff recommended and then went at it.
Pedal feel both on and off was much improved, particularly when trailing off like in the turn 7 hairpin where in my car you’re braking from 130 to the high 40mph range on a bumpy surface that changes from asphalt to 70 year old concrete (Sebring was built in the 40’s as a B17 training base) and back to asphalt. Lap after lap after lap consistency, all weekend long.
I got 227 laps over parts of 7 days out of the first set of pads. Fronts and rears wore relatively evenly which is a major difference from the previous setup where the fronts wore faster. I didn’t swap the pads side to side as Essex recommends.
For the second set of pads I took Jeff up on his offer to try a new Ferodo compound; the 3.12. My initial experience wasn’t positive. Braking as I usually had invoked the ABS regularly and wasn’t comfortable. I did two sessions and when rain moved in, I packed up and decided to change back to 1.11s for the next event. Got busy, forgot about doing the change until there wasn’t time so I figured I’d give the 3.12s another ago and swap at the track if needed.
For whatever reason the second time was a charm. The 3.12s want a lighter initial application but after that offer the same great modulation as the 1.11s. I got 246 laps out of that set, replacing all four at the same time. And again, pads weren’t rotated midlife due to owner brain fade.
All four discs were changed (after 473 laps over parts of 14 days) after the 2nd set of pads wore out. The fronts had maybe two more sessions in them and the rears maybe 4 – 5 sessions but I decided to go with a clean slate and not have to change in the heat at Sebring.
For longevity comparison purposes, RE10 and DS1.11s typically gave me 180 – 195 Sebring laps with the previous setups and the most laps I ever got out of a set of 350mm Giro fronts was 350; rears were closer to 420.
Increased consumable life seems to indicate the Essex / AP setup runs cooler. Additional, albeit anecdotal, evidence of this is tire pressure increase over the course of a session. I couldn’t figure out why I started having to bleed 1 – 2 psi less out of the front tires than I historically had to when coming in mid-session as ambients rose toward the 90s. The brakes were the only change made to the car, so I believe it is due to them running cooler. The fronts at least.
In addition, there is a very significant unsprung weight reduction with the Essex / AP BBK over stock. I don’t have the figures here but am sure it’s available on the Essex website.
Finally, and at long last, they’re the **** and I love them!
02-19-2019, 03:37 PM
Essex decides on what size discs to use in our brake kits, and we do so based on a tremendous amount of experience. The odd sizes (372mm and 365mm) were chosen specifically based around needs. We could have went with a generic 380mm setup, but 380mm is much, much harder to stuff inside 18" wheels in most cases, which is what the wheel size that many of our most popular applications run. When we drew up the specifications for these discs, we looked at what we needed, and didn't just follow an industry trend or what everyone else has done in the past. 
