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Statement from JRitt@essex: “Vane Count – AP Racing C7 Z51 J Hook discs have 72 vanes, vs. what appear to be 24-48 on the RB discs. More vanes increases airflow and disc face stability.”
Our response:
Vane count for most brake manufacturers (including AP) is based on single count (ie. 48, 52, 72 etc.), however RB’s cooling vanes are variable between the inner and outer rotor edge (typically 36 inner and 54 outer) to optimize the cooling effect. The traditional single vane count is certainly not the primary factor for rotor cooling; the design of how to effectively cool the disc is what really "counts".
RB’s convergent vane design utilizes wide inlets and narrow outlets. Velocity of airflow increases as it enters through wide inlets, and exits through narrow outlets. Wider inlet can maximize the airflow at lower pressure, while its velocity decrease through (more) cooling vanes to absorb more heat from the disc before exiting to the outlet.
Conventional or competitions' "single vane count" design has a flaw in which due to the rotor outer diameter is larger than inner, so it ends up being "Divergent" vane which is opposite to optimizing the air flow for effective cooling per Bernoulli's principle illustrated below.
Benefits of the convergent vane design can be supported and better understood with review of Bernoulli’s convergent duct principle.
Bernoulli's theorem states: "When a gas or fluid is flowing through a convergent duct (as in nozzle stator vanes or venturi), its speed will increase and its temperature and pressure will decrease.”
t1 = Inlet air temperature
t2 = Outlet air temperature
Assume the air flow and inlet air temperature are constant, we want the outlet air temperature to be as high as possible to maximize the cooling effect.
RB's convergent vanes optimize the cooling effect not only can remove more heat and keep the disc cooler but result a more uniform disc temperature across the braking surface which is essential to keep the rotor from warping and cracking.
The advantage of RB two piece rotors last more than 20 track days and run 100-125 deg F cooler was officially recognized and reported by an NSX track racer in 2006.
I'm sure RB products are great, but the obvious benefit to more vanes, not counting the science/argument of airflow, is simply that there is more material, which in turn increases thermal capacity. It's similar to why a larger rotor diameter can handle more heat than a smaller one. More mass allows for more absorption and dissipation of heat. Increased thermal capacity and stability.
Whether or not each particular vane design dissipates heat better or faster can be a valid discussion, but it's just part of the equation. I'm sure RB's rotors dump tons of heat.
More mass/rotor, is also going to cost more. I would expect 380x34mm rotor with 72 vanes to cost more than the same with 48 vanes. I ran AP (72 vane) discs on my 7.1RS, and I have yet to find another brand which could last as long as they did. PFC's couldn't, and they also have 48 vanes. Is that the reason? I don't know. I do know there are 72-vane AP Indy-car discs being used on 987's which dump insane amounts of heat, and last longer than anything else, but they are also quite pricey.
My observations aren't scientific, they are just real world use, on the same pads and tires, at the same tracks. We all know RB, PFC, AP, and others offer great products......
Mvez, did you find the AP slotted rotors lasted along than the Brembo Type 3s?
Given brembo owns AP, I would expect similar performance from their 72 vane setup. Not personally used them, but users always have great things to say too.
Given brembo owns AP, I would expect similar performance from their 72 vane setup. Not personally used them, but users always have great things to say too.
Oh interesting, I didn't know that Brembo owned AP.
Oh interesting, I didn't know that Brembo owned AP.
Actually brembo type 3/5 endurance are 72 vane, and more comparable to the AP discs. This is a great article which brembo even says their 48 vane holds more heat than 72 vane.
For DE, I want a rotor that lasts the longest. Enduro style, 72 vane seem to deliver that. PFC offered an enduro ring that is 34mm compared to 32mm thick but still 48 vane. It wasn't as good as AP 34mm thick, 72 vane.
Actually brembo type 3/5 endurance are 72 vane, and more comparable to the AP discs. This is a great article which brembo even says their 48 vane holds more heat than 72 vane.
For DE, I want a rotor that lasts the longest. Enduro style, 72 vane seem to deliver that. PFC offered an enduro ring that is 34mm compared to 32mm thick but still 48 vane. It wasn't as good as AP 34mm thick, 72 vane.
The specific Indy-Car discs you mentioned for the 987 above are a Brembo disc sold by Charlie at Wrightwood racing, not an AP one. Since Wrightwood offered both AP and Brembo discs with their assemblies, a mixup is easy.
Brembo Type 5s last longer than the 3s, but the 3s have more "bite". Type 5 vs 3 is same disc, but the slots affect the way the discs and pads wear. We run the 5s for endurance events and anytime we can on the front axle of a race or DE car.
Which vane count is really "better" depends on how you use brakes and disc temps. Even with a 380mm 72 vane front disc at Daytona, sometimes the discs run too cold (long straights, etc..), causing cold temp wear.
In that case, we block off ducts. Most rear discs are only run as a 48 vane because brake temps are already low in the rear, over cooling only makes disc life worse.
Above discussion was not aware to us until another member post the following thread, when we were informed by one of our customers. Racing Brake rotors vs AP Racing J hooks
Aside from JR's guess of RB's vane "count" his ..."More vanes increases airflow and disc face stability". was simply not true. The truth is the more of the vane, the less of air flow. Nor can I understand how the vane count is related to disc surface stability.
We felt honored when we received competitions' critics although most of them are groundless and false, but we take that opportunity to reiterate our brake design with Bernoulli's principle, and other supporting theories & users' feedback to prove why RB brake works better, instead of using marketing gimmick or irresponsible criticism on others.
No offense, but there is a reason that companies like PFC, AP, and brembo all offer both sprint and endurance type rotors. Being professionally tested, raced, and proven might have something to do with it. Those are not "gimmicks".
There is a reason why every endurance style rotor is heavier than a sprint type. You are in the business of brakes and should know this. Mass matters, In addition to how much cooling the vanes create.
I'm sure your products are great, in fact I'm ordering a set of your stainless Pistons for my 987 as we speak, but you aren't going to gain lots of traction obsessing over vane design. The patented "kangaroo paw" vane design of DBA looks compelling too, but that doesn't mean I'm going to use them either....I'm sure some rotors do cool better than others, and RB may be the best, but again that is part of the equation.
For the DE guy, they want the rotor which is going to last the longest, and that is almost always a heavy duty, endurance type 72 vane rotor.
I know 996 gt3 guys who get more life out cheap, heavy stock cayenne rotors than some fancy 2 piece setups. Why? It's a big *** , heavier heat sink with adequate cooling.
Above discussion was not aware to us until another member post the following thread, when we were informed by one of our customers. Racing Brake rotors vs AP Racing J hooks
Aside from JR's guess of RB's vane "count" his ..."More vanes increases airflow and disc face stability". was simply not true. The truth is the more of the vane, the less of air flow. Nor can I understand how the vane count is related to disc surface stability.
We felt honored when we received competitions' critics although most of them are groundless and false, but we take that opportunity to reiterate our brake design with Bernoulli's principle, and other supporting theories & users' feedback to prove why RB brake works better, instead of using marketing gimmick or irresponsible criticism on others.
Warren-RB
Sprint Rotors: Aggressive slot type, thinner disc (32 mm), wider airgap, 72 vane. Made for light weight, better airflow, get changed out every 1-2 race weekends (55 mins to 2 hr 45 mins races).
Enduro Rotors: Slot type to help pad life & temps, thicker disc for more material (34 mm disc), thinner airgap to extend life and avoid temp swings, 72 vane. Made for longevity and consistency.
You can run sprint rotors for enduro races but you have to manage your temps and rotor life. We could do that for some long races, but usually we choose not to push it.
No one rotor is good for everything. Companies like Brembo and AP have the right product and product range so they can use the right product for the right use.
That's why they have 85% of the professional race market (60% Brembo/25% AP). We sell Brembo & RT because they have sprint and enduro rotor / pad options for almost all Porsche options giving us many options.
Teams have tried your products, and they don't seem to hold up. I will just leave it at that.
I have no idea why you're chasing us around the internet trying to discredit Essex/AP Racing (here, corvette forum, m3 forum, etc.). Your spamming post in this thread about our discs back in January was in poor taste and etiquette, but I didn't think it was worth addressing directly at the time. I'm also not out on the web spreading vicious lies about brake technology in general. Sifting through the many thousands of words I've written on the web about brakes isn't going to unearth any major conspiracies or technical falsehoods. All that is going to do is waste your time. My comments, observations, and opinions come from the couple hundred years of collective brake knowledge and racing experience we have at Essex Parts and AP Racing. In other words, I'm not making this stuff up! As KA Motorsport points out, everything we do has been proven time and again at the elite level of racing. In recent years we've simply made a more concerted effort to bring that championship-winning technology to the common enthusiast at a palatable price, and that has been my role within the company. Because of that, our customers win.
It boggles my mind that you would invite potential customers to look at the corvette market as a shining example of Racing Brake's superiority over AP Racing. Out of all the markets we service, Corvette is possibly our crown jewel. We offer a huge array of products for the C5/C6/C7, including approximately 30 different big brake kits and 2-piece disc kits! Our Essex Designed AP Racing kits are considered the gold standard solution, and we've had countless customer championships, wins, podiums, and lap records. That success starts with the fastest Corvettes in the world, the factory Corvette C7.R's, who just won the 24 Hours at Daytona a few weeks ago (ironically, passing a Porsche to take the 1-2).These cars are running the exact same disc design we're selling to 991 GT3 owners! Below is pic of the Competition Brake Kit we sell for the C7 Corvette road car, lined up next to the C7.R brakes. Notice any similarities...AP Racing Radi-CAL on a high-vane count AP Racing J Hook disc. This is a perfect example of bringing technology that was previously reserved for the top tier of racing into the enthusiast aftermarket.Also below is the C7.R winning Le Mans for the 8th time last summer on AP Racing J Hook discs...
We've also been supplying Action Express with AP Racing brakes for their Corvette Daytona Prototypes. Those are 200mph cars. Before switching to an AP Racing carbon/carbon system (per a rule change), they won the championship in 2012 and a slew of races on AP Racing 355x32mm, 72 vane discs...the exact ones we sell to retail customers in our Competition BBK's.
How can one possibly argue that our discs are somehow inferior, or that the technology is in some way flawed? Just as astonishing, how can one claim more success in the Corvette market? The fastest Corvettes on the planet run AP Racing J Hook Discs, period.Our Essex Designed AP Racing J Hook Discs for the 991 GT3 use the exact same design principles and technology as the cars highlighted above, so all of the success you see those cars achieving is directly applicable to the customers on this forum.
Just as confusing to me...why on earth would you post a link to a thread on another forum in which someone at a competing manufacturer claims to have a four foot tall stack of your failed discs on hand (post#10)?
In closing, I would absolutely invite all Porsche GT3 owners to peruse the Corvette forum and search for my name "JRitt@essex". What you'll find is a small army of Corvette owners whom Essex/AP Racing has helped go faster and squeeze more enjoyment out of their cars at the track every weekend.
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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
Last edited by JRitt@essex; 03-04-2016 at 11:39 AM.
03-02-2016, 04:47 PM
Racing Brake rotors vs AP Racing J hooks
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The fastest Corvettes on the planet run AP Racing J Hook Discs, period. Our Essex Designed AP Racing J Hook Discs for the 991 GT3 use the exact same design principles and technology as the cars highlighted above, so all of the success you see those cars achieving is directly applicable to the customers on this forum. 
